An electronic circuit, preferable as a sensor node, has a highly sensitive radio function and is capable of performing a low-power-consumption operation. The electronic device has a board; a connector for connecting a sensor; a first signal processor circuit receiving an input of sensor data from the sensor through the connector and forming transmission data; and a second signal processor circuit converting a transmission signal from the first signal processor circuit into a high-frequency signal. The connector and the first signal processor circuit are mounted on a first surface of the board, and the second signal processor circuit is mounted on a second surface of the board.

The present invention relates to an electronic circuit equipped with a radio communication function. More specifically, the invention relates to a small and low-power-consumption electronic circuit effectively applied to construct a sensor network system.
In recent years, there has been considered a network system (hereinafter abbreviated as "sensor net") for capturing in real time various real-world information into an information-processing device by adding, to a sensor, a small electronic circuit having a radio communication function. For the sensor net, widespread application is considered. For example, there is also considered the application to a medical technology for: always monitoring the pulse etc. through a small finger-ring type electronic circuit in which a radio circuit, a processor, a sensor, and a battery are integrated; transmitting a result of the monitoring to a diagnostic unit by radio communication; and determining a health condition based on the result of the monitoring (see Non-Patent Document 1: Sokwoo Rhee et al, "Artifact-Resistant Power-Efficient Design of Finger-Ring Plethysmographic Sensors", IEEE Transactions On Biomedical Engineering, Vol. 48, No. 7, July 2001, pp. 795-805).
However, to bring the sensor net into even wider practical use, it is essential that an electronic circuit having power supply of a radio communication function, a sensor, and a battery, etc. (hereinafter abbreviated as "sensor node") is in a maintenance-free state for a long time and sensor data is being transmitted and the external dimension thereof is reduced. For this reason, the development is in progress to provide an ultra-miniature sensor node that can be mounted anywhere. At the present stage, it has been contemplated that the sensor node, which is practically available for about one year without exchanging its battery, is required from the viewpoint of both of its maintenance and usability.
As described above, the sensor node is required to be very small and, concurrently, to be operable with low power consumption. For example, Non-Patent Document 2 (Crossbow, "Smarter Sensors In Silicon" (online) (Retrieved on Feb. 16, 2004), Internet (URL: http://www.xbow.com/Support/Support pdf files/Motetraining/Hardware.pdf) describes a prototype of a small sensor node called "Mica2Dot" having a diameter of about 3 cm. The Mica2Dot is configured of an RF chip having an integrated functionality necessary for radio communication and a low-power-consumption processor chip. This prototype performs an intermittent operation in such a manner that the prototype is held in a standby mode for 99% of operation time, and is intermittently activated only for remaining 1% of the operation time and wirelessly communicates the result, whereby the operation can be performed for about one year with a small battery. This sensor node performs the radio communication by using, for example, frequency bands ranged from 260 to 470 MHz and 902 to 928 MHz, etc. which are usable without a license in the United States. In general, to perform radio communication, a specific transmitter/receiver device preliminarily licensed or authorized must be used, so that use is greatly restricted. Under such circumstances, since a license-free frequency is used, the device can be mounted without using much labor and cost and the system construction becomes easy, so that it is advantageous to use the above-mentioned frequency bands. Particularly, in the United States, the maximum values of transmission power are regulated as being 11 mV/m or lower in a band of 433 MHz and 50 mV/m or lower in 900 MHz (at a distance of 3 m from a transmission point in any of the cases), wherein even in the license-free frequency bands, when the above-mentioned frequency bands for which the limit values are relatively reduced are used, excellent communication performance and low costs are implemented.
Nevertheless, however, radio wave regulations differ depending on the nation, location, and the like. For example, in Japan, the radio wave regulations are described in Non-Patent Document 3 ("Popularly Used Micro-force Radio Devices" (online) (Retrieved on Feb. 17, 2004), Internet (URL: http://www.circuitdesign.jp/jp/technical/technical_pdf/bijaku.pdf.PDF), and tolerances of electrical field intensity for use in the license-free frequency bands are not necessarily alleviated.
Also, Non-Patent Document 4 ("Data Sheet CR2032" (online) (Retrieved on Feb. 21, 2004), Internet (URL: http://www.maxell.co.jp/e/products/industrial/battery/pdf/CR2032_Data Sheet.pdf) discloses a small button battery suitably usable as power source of the sensor node.

Sensor node and circuit board arrangement


The disclosure prevents, with improved reliability, an IC tag from being broken, while ensuring overall flexibility of the IC tag. The IC tag 100 is provided with a covering 140 made of an elastic material, which covers at least the side of the IC tag 100 on which an IC chip 130 is mounted and has a thickness that is larger in its portion 140a that covers a region about the IC chip 130 than in its portion 140b that covers a region outside the region about the IC chip 130. The covering 140 is configured in such a way that at least a part of a boundary of the portion 140a of the covering that covers the region about the IC chip 130 and the portion 140b of the covering that covers the region outside the region about the IC chip 130 has a curved shape.

Hither-to, the RFID technology has been widely used for the purpose of product management. To utilize the RFID technology, IC tags are attached to linen goods such as uniforms or bed sheets used in a hotel. The IC tags attached to such goods need to have flexibility. For this reason, an IC tag made up of a film member provided with an antenna part and an IC chip mounted thereon is used.
In the case where IC tags are attached to linen goods, the IC tags will be washed with the linen goods in the laundry. Therefore, the IC tags attached to such goods need to have strength against external forces and resistance against solutions used in the washing process. As a technique employed to meet this requirement, it is known to cover the body of an IC tag with a covering made of a rubber, resin or the like (see for example, Japanese Patent Application Laid-Open No. 2005-056362 or Japanese Patent Application Laid-Open No. 2007-148735).
However, if the covering that covers the entirety of the IC tag body is not sufficiently thick, the IC chip may break. Moreover, if strong bending and/or twisting force or a pushing load acts on the IC tag in the dewatering step in the washing process, stress will concentrate to a portion of connection of the IC chip and the antenna part, possibly resulting in breakage of the portion of connection. On the other hand, if the covering that covers the entirety of the IC tag is too thick, a problem of insufficient flexibility of the IC tag will arise.
As a solution, it is known to make the thickness of the covering for the portion of the body of the IC tag about the IC chip larger than thickness of the covering for the portion outside the portion about the IC chip (see for example, Japanese Patent Application Laid-Open No. 2007-004323 or Japanese Patent Application Laid-Open No. 2010-122764). Such IC tags can have sufficient overall flexibility, while achieving protection of the portion of connection of the IC chip and the antenna part by relatively thick covering.


The present invention is an action figure with the ability to shoot water by means of an air pressurized water chamber. The action figure includes a body which is at least partially hollow and at least one body orifice. A water storage reservoir is connected to the body and it has a separate, remote water source for adding water thereto. The water storage reservoir is connected to a pumping and pressurizing means which in turn is connected to the remote water source. The pumping and pressurizing means for pumping the reservoir water and to pressurize the air therein after the water has been added There is an avenue of release which runs from the reservoir to a nozzle and a water release means for regulating the fluid flow through the avenue of release. The water release means is operably connected to the avenue of release and extends outwardly therefrom to permit manual operation. A nozzle at the end of the avenue of release controllably releases water when the water release means is actuated.

1. Field of the Invention
The present invention is directed to an action figure with the ability to shoot water by means of an air pressurized water chamber and a separate, remote water source. More specifically, it relates to an action figure having movable extremities and having a separate water source, pressurized chamber and separate pumping and pressurizing mechanism and releasing mechanism for drawings, pressuring and shooting liquid therefrom.
2. Information Disclosure Statement
Many toys and similar products have been developed over the years which pertain to dispensing water. Some have been to combine function with entertainment for children, e.g. shampoo dispensing, others have been to mimic or recreate bodily functions, e.g. crying, urinating, etc., while others have been for pure entertainment, e.g. water spraying with figures or dolls.
The following patents represent a chronological history of such diverse prior art:
U.S. Pat. No. 928,059, describes a soap dispenser having a force pump with animated features. The force pump is immersed in liquid, e.g. soap and the pump stroke causes direct dispensing.
U.S. Pat. No. 1,266,106 describes a toy whale with wind up, spring loaded wheels which move a reciprocating plunger which causes pushing force on a flexible reservoir. When this is filled with water and the whale is moving, the plunger causes the whale to "blow" water.
U.S. Pat. No. 1,893,972 shows a novelty gasoline pump with an elephant encasement, the trunk of which is the pump hose. The hose is extendable and automatically retractable through the elephant's trunk.
U.S. Pat. No. 3,388,835 describes a dispenser for lotion or bubble bath. The device has a container of toy-like character, a dispensing mechanism including a plunger tube attached to one end of a suction cylinder. The plunger tube extends downwardly into the liquid contained within the container, the plunger tube being attached at the lower end of the suction cylinder. A sidewardly extending flexible tube out of which the liquid is dispensed, is included, and an upper plunger tube is connected to the upper end of the suction cylinder, the upper plunger tube having a press-button at its upper end.
U.S. Pat. No. 3,420,412 sets forth a spraying device enclosure. It has an attractive hollow body simulating an animal in shape and of soft and flexible material to enclose a pressurized spray can. The body has an adjustable opening on the bottom for introduction of the can and opposing openings at the top, one of the openings permitting projection of the mouth of the spray can such as the bill of an animal, and the other opening permitting the introduction of the user's finger for operation of the plunger of the spray can.
U.S. Pat. No. 3,769,745 shows a toy doll which will produce tearing and simultaneously move its arms (in response thereto) to provide the appearance of a crying doll. A fluid reservoir, located in the head of the doll includes ducting to carry the fluid from that reservoir to the eyes of the doll. The eyes of the doll are arranged with respect to the ducting so as to deflect the fluid passing therethrough to create the appearance of a crying or tearing doll. An elastically compressible bulb, connected to the fluid reservoir, is located in the passageway between the head and the body of the doll and is aligned along the axis of rotation of the head. When the bulb is compressed, the fluid contained therein is displaced and passes from the fluid reservoir to the eyes of the doll. The tearing system has no overflow or air intake ports inside the doll.
U.S. Pat. No. 3,775,901 describes a child's doll with an internal reservoir into which a liquid may be introduced through the mouth orifice of the doll. The reservoir is also provided with a discharge valve whose opening is effected by the close proximity of a permanent magnet; such a magnet being provided attached to a training seat with chamber-pot. The doll is provided with an orifice at its lower extremity through which it can eliminate fluid when placed on the training seat.
U.S. Pat. No. 3,789,539 is directed to a weeping doll, having a head with eye sockets and an open mouth formed therein, is provided with a gravity influenced weeping device for causing the doll to weep when placed in a generally horizontal position. The weeping device includes a liquid inlet tube located adjacent the open mouth and a flexible reservoir tank in liquid communication with the inlet tube. A selectively operable valve is located in the inlet tube for opening the inlet to permit liquid to flow through the mouth to the reservoir. The inlet tube is provided by a rigid housing which defines a liquid flow conduit between the flexible reservoir and the eye sockets of the doll and means is provided for compressing the flexible reservoir when the doll is in a generally horizontal position to force liquid from the reservoir through the conduit to the eye sockets, in order to simulate weeping or tearing.
U.S. Pat. No. 3,855,729 describes a tearing reservoir which is pressurized by inflatable sack connected to a bellows mounted in figure toy head and receiving air from waterimpervious, hollow torso in fluid communication with bellows through a neck plug connected to the bellows and the torso in such a manner that water entering head when figure toy is immersed will not pass into torso. A reed-type noise maker may be mounted in the neck plug.
U.S. Pat. No. 4,193,517 is directed to a large capacity water squirting implement in the form of a cane. This water squirting implement utilizes a reciprocal plunger hand pump which is mounted at the top of a hollow, elongated tube which provides the large water storage capacity. A head is slidably secured to the top of the cane, enclosing the pump in such a way that reciprocal motion of the head is transmitted to the plunger of the pump to cause squirts of water to be emitted from a tube extending from the outlet of the pump to the exterior of the head.
U.S. Pat. No. 4,578,045 covers an action figure such as a human. The action figure includes two arms mounted to the figure's torso for rocking movement toward the torso about laterally spaced axes, the action figure also including two legs that are mounted for pivotal movement to the torso in a scissors-like fashion. Integral with the rockable mounting means for each arm is an inwardly extending shank, the shanks projecting into end portions of a coil spring. When either arm is moved laterally toward the side of the torso, the spring is flexed into a V-shaped configuration. A link extends downwardly from the center of the spring so that the flexing action imparted to the spring causes the link to move downwardly or upwardly. Each unit for pivotally mounting the legs includes a crank pin that is receivable in forwardly and rearwardly located slots at the lower end of the link. The arms can be independently swung from a position adjacent the sides of the figure to overhead or outstretched positions without affecting their ability to oscillate the legs in a scissors-like manner and thereby simulate running, swimming and kicking movements.
U.S. Pat. No. 4,601,672 is directed to toy actions figures which include upper and lower hollow torso portions. An actuating mechanism is contained in the upper torso and acts through a helical gear mechanism to rotate the lower torso portion and the legs attached thereto about a longitudinal axis when one of figure's arms is swung from a diverging relation toward one side of the figure. A spring is used to return the actuating mechanism and the limbs associated therewith back to their normal or unactuated positions. Another spring releases or disconnects the lower torso portion from the actuating mechanism should the child attempt to twist the two torso portions relative to each other by using too much force.
U.S. Pat. No. 4,623,319 covers an activity toy with a body including a hollow cylindrical portions supported on a base and having pivotally mounted arms has a hollow upper member including a skull with extrusion openings. The bottom of the upper member has a loading opening for a plastic amorphous solid substance. Attachable about and spaced from the skull is a clear plastic mask formed of separable halves clamped together at the bottom by the engagement of hooks and tabs and at the top by a detachable hairpiece. Near the bottom, the mask is maintained in a relatively tight relation to a flange on the hollow upper member. The upper member with the mask attached is secured to the body by a bayonet lock. Within the body is a piston with diametrically opposed gear racks that are engaged by gear segments on arms pivotally mounted to the body. Movement of the arms from an upraised position down to a lower position drives the piston into the hollow member through the loading opening to extrude the plastic amorphous substance out of the extrusion openings in the skull and fill the clear plastic mask.
U.S. Pat. No. 4,630,756 covers a liquid squirting simulated creature comprised of a front section having a body, legs and head, and a rear section which is assembled thereto. The front section is comprised of top and bottom elements defining a cavity therebetween and front and rear apertures, as well as apertures extending along the sides thereof through which a multiplicity of legs extend. The rear section is a resiliently compressible bulbous member providing a chamber therewithin to contain fluid and having a neck portion extending through the aperture in the rear wall of the front section. A tubular conduit is seated in an opening in the neck portion of the rear section and extends to a front aperture in the front section so as to provide the conduit for discharge of fluid from the chamber therethrough. The leg members are comprised of a web on each side interconnecting a multiplicity of legs on that side of the front section, and flexible portions which extend through apertures along the sides of the front section.
U.S. Pat. No. 4,723,931 describes various patterns of receptor holes formed in the torso, arms and legs of a plastic toy action figure to permit various accessories, also of plastic, having compliant press-in pins to be selectively added to and removed from the toy figure. Additionally, a rotatable coupling mechanism extends through the torso, the coupling mechanism having a receptor hole at each end thereof, the holes in the coupling mechanism being in a predetermined relation with respect to prearranged patterns of receptor holes in the front and rear of the torso. In this way, accessories can be plugged into the ends of the coupling mechanism. The coupling mechanism is provided with two sets of facial teeth or serrations that are normally resiliently urged into engagement but which disengage if the coupling mechanism is subjected to an excessive amount of twisting force, thereby avoiding breakage. Associated with the coupling mechanism is a sound creating device that produces an audible clicking as the coupling mechanism is rotated in either direction.
U.S. Pat. No. 4,768,681 describes a water action toy which is worn on a child's hand by means of a glove secured to and underneath a housing in which a water reservoir, a water pump, an electrical motor and a battery pack are housed. A pair of actuators are mounted on a thumb sheath and a forefinger sheath of the glove. When the actuators are brought together by finger manipulation, the motor drives the pump to eject water in a series of spurts from the toy.
U.S. Pat. No. 4,982,874 sets forth a shampoo dispensing container in the shape of an action figure, such as an army figure, and has a fluid pumping system that operates to dispense shampoo from the container in an exploding type pattern as one of the arms of the action figure is operated in a combat type movement.
U.S. Pat. No. 5,071,387 describes a figurine-shaped toy that squirts water out of its mouth by cranking an arm.
U.S. Pat. No. 5,083,965 covers an interactive doll system incorporates both liquid handling elements for receiving liquid through the mouth of the doll when the doll is in a first range of positions, then dispensing that liquid through the eyes of the doll when the doll is in a second range of positions or through an anal opening of the doll when the doll is in a third range of positions. It also incorporates an electronic assembly for sensing the attitude and motion of the doll, as well as feeding of the doll, and for producing a range of sounds in response thereto, including sounds produced randomly at times in response to motion of the doll.
U.S. Pat. No. 5,073,140 discloses toy action figures and detachable accessories therefore incorporating audio generating apparatus. The audio generating apparatus is entirely contained within the accessory and generates both speed and sound effects. The detachable accessories have a configuration and visual appearance coordinated with the configuration and visual appearance of the toy action figure. For example, the accessory may be a backpack configured and having a visual appearance to coordinate with a soldier, spaceman or policeman action figure. The audio generating apparatus includes separate controls for causing the audio generating apparatus to independently generate speech and sound effects. The accessories in configuration, appearance and sound content are made to be attachable and applicable to different types of action figures.
U.S. Pat. No. 4,239,129 to Gary F. Esposito describes a water pistol and/or flashlight structure which includes a reciprocal pump within a liquid chamber or tank located itself within the gun housing. The pump is used to pressurize air within the tank after the water has been added, and a trigger is used for subsequent release of the water. Battery operated lights and sound are also provided.
U.S. Pat. No. 3,578,789, issued to Giampiero Ferri, describes a water pistol which includes a main liquid reservoir and a pressurized liquid reservoir contained within the main liquid reservoir. The trigger-actuated pump is used with a manually operated three way valve to selectively supply liquid: (a) from the pump to the pressurized reservoir; (b) from the pump to the nozzle and to the pressurized liquid reservoir; or, (c) from the pressurized liquid reservoir.
Notwithstanding the plethora of prior art, none teaches or renders obvious the present invention.

Action figure with remote water source for shooting water


A press section is provided for a papermaking machine having an Extended Nip press before a conventional press section such as a Beloit Corporation Tri-Nip or Twinver press. A Beloit Corporation Extended Nip.RTM. press or similar type press, preferably of the closed blanket type, is installed before a conventional two or three nip press and thus reduces the problem of the web sticking to the center roll in the conventional press. The use of an Extended Nip press in front of a conventional pressing section can also increase the bulk of the web being formed. The pressing section of this invention is particularly useful for pressing webs formed of 100 percent tropical hardwood fibers which contain resinous particles which can cause problems in sticking to the center roll.

Paper is manufactured on a papermaking machine as a continuously formed web of paper. A papermaking machine has a wet end where the web is formed by depositing paper forming fibers from a dilute stock of fibers suspended in water. The fibers are deposited onto a forming section or screen in what is known as the forming process. Water is removed from the forming wires by drainage through these screens which is often aided by suction boxes located beneath the forming wire.
As the web leaves the forming wires it passes beneath a suction pick-up roll. The web leaves this roll and the forming section containing approximately 20 percent fiber by weight and enters the press section of the papermaking machine. In the press section of the papermaking machine the paper web fiber content is increased to a level of about 40-50 percent fiber by weight by pressing the web to remove water. From the press section the web enters the drying section where a series of steam heated dryer rolls dry the paper to about 95 percent fiber by weight. After the paper has passed through the drying section the web is subjected to one or more calenders to smooth and improve the surface finish of the web. The web is then wound into a reel for removal from the papermaking machine.
The press section of a papermaking machine is typically composed of two or three nips, and may employ a third nip of the Extended Nip press type. An Extended Nip press employs a concave shoe which engages a blanket and the web against an opposed roll. A lubricant film is disposed between the blanket and the shoe which supports the blanket in its passage through the Extended Nip press. The nip of an Extended Nip press is typically about ten inches wide and the backing roll is in some configurations heated to between 300 and 700 degrees Fahrenheit.
A particular papermaking machine will often need to be designed to produce a particular or narrow range of paper types from a particular stock. One type of stock which can be particularly difficult to work with is stock make from 100 percent tropical hardwoods. Although temperate forests are dominated by just a few species of trees, tropical forests contain a large number of different species which invariably must be harvested together. Even where managed forests are harvested, a large number of tropical hardwoods species will typically be grown together to maintain a diverse ecosystem and minimize the susceptibility of the forest to disease and insect damage. Thus the properties of tropical hardwoods pulp can be difficult to characterize. Tropical hardwood pulp contains a fair amount of resinous particles which can cause problems in the drying section of a papermaking machine. A web formed from tropical hardwood fibers can stick excessively to the press rolls. The tropical hardwood pulp fibers are weak and this can increase the number of web breaks experienced in a typical machine day.
What is needed is a pressing section for a papermaking machine designed to improve the performance of a papermaking machine working with selective paper forming stocks including 100 percent tropical hardwood fibers.

Method of pressing a paper web of tropical hardwood fibers


Methods and apparatus are provided for the recovery of nucleic acids from a nucleic acid-containing material by which nucleic acids can be rapidly and easily recovered at a high purity without deteriorating the yield. The methods are composed of step 1 for promoting the release of nucleic acids from a nucleic acid-containing material, step 2 for mixing the released nucleic acids with an accelerator substance for the binding of nucleic acids to a solid phase, step 3 for bringing the mixture in contact with a solid phase bondable to nucleic acids, step 4 for isolating the solid phase from a liquid, step 5 for washing the solid phase with a solution containing a salt, and a step 6 for eluting the nucleic acids from the solid phase. Accordingly, nucleic acids at a suitable purity for genetic tests or gene analyses can be rapidly and easily recovered without the use of hazardous substances. The apparatus may contain a reactor, at least one pipette, a purified product container, transport mechanisms for the reactor and purified product container, motors to control the pipette and transport mechanisms, a mechanical control unit to control the motors, and a computer that controls the mechanical control unit.

1. Field of the invention
The present invention relates to a method for the recovery of nucleic acids from a nucleic acid-containing substance. In more detail, it relates to a method for the recovery of nucleic acids, which is suitable for an automatic device for the recovery of nucleic acid components as endogenous or exogenous genes from humor components for gene diagnosis by means of nucleic acid assays, or suitable for an automatic device for the recovery of plasmid DNAs from recombinant E. coli or the like for base sequencing of nucleic acids.
2. Description of the Related Art
A multitude of genetic technologies have been developed based upon advances in molecular biology, and a number of morbid genes have been isolated and identified according to these technologies. As a result, molecular biological techniques have been adopted as techniques for diagnosis or examination in the field of medical care so as to enable diagnosis which have been unable to conduct or to shorten the period of examination remarkably.
The significant advances largely owe to gene amplification techniques, in particular to polymerase chain reaction (hereinafter referred to as PCR: Saiki et al., Science, 239,487-491(1988)) techniques.
The PCR technique enables nucleic acids in a solution to amplify sequence-specifically so that it provides, for example, an indirect proof of the presence of a trace quantity of a virus in serum by amplifying and detecting nucleic acids as the viral gene.
The PCR technique is, however, somewhat disadvantageous in the use for clinical daily examinations. In particular, there are some difficulties in extraction and purification steps of nucleic acids in a pretreatment according to this technique, whereas the extraction and purification steps of nucleic acids have been indicated to be key steps (Ooshima et al., JJCLA 22(2),145-150(1997)).
These difficulties are attributed to inhibitory factors remaining in the purification step of nucleic acids, and known inhibitory factors include hemoglobin in blood, surfactant used in the extraction step and the like.
In addition, the extraction step requires a complicated procedure and a large amount of skilled labor. Therefore, this step is an obstacle to a new introduction of the genetic test into laboratories of hospitals, and the automatization of this step has been demanded.
On the contrary, plasmid DNAs are frequently used as materials for genetic engineering, and automatization of the extraction and purification steps of nucleic acids has been demanded from the viewpoint of labor savings in institutions for molecular biological research, as well as in the laboratories.
As a method for the recovery of nucleic acids from a biological sample at a high purity and being free from inhibitory factors, there has been known a method for the recovery of nucleic acids comprising the steps of allowing a surfactant to act on a biological sample in the presence of a protease to release nucleic acids, mixing the released nucleic acids with phenol (and chloroform), repeating aqueous phase (water phase)-organic phase isolation by a centrifuge several times and then recovering the nucleic acids as sediments from the aqueous phase with the use of an alcohol.
This method, however, has some disadvantages due to the use of an organic solvent such as phenol, a toxic substance, in the steps. To be more specific, an organic solvent such as phenol has the possibilities of dissolving plastics of a device used for the recovery of nucleic acids and of deteriorating the device.
Further, the method noted here requires for a centrifugation step to be effected. This leaves the problem that automation is made extremely difficult to achieve in putting and taking containers into and out of the rotators of a centrifuge and also in fractionating the resultant centrifuged solutions.
In addition, the use of an organic solvent such as phenol requires complicated treatments for discarding the organic solvent.
As other method for the recovery of nucleic acids than the method utilizing the aqueous phase-organic phase isolation, there have been reported a method for the recovery of DNAs from agarose gel utilizing the bonding properties of nucleic acids to the surface of glass in the presence of a chaotropic agent (B. Vogelstein and D. Gillespie, Proc. Natl. Acad. Sci. USA, 76(2),615-619(1979)), or a method for recovering plasmid DNAs from E. coli (M. A. Marko, R. Chipperfield and H. C. Birnboim, Anal. Biochem, 121,382-387(1982)).
A method for the recovery of nucleic acids from a biological sample by means of a simpler procedure is described in Japanese Unexamined Patent Publication No. 2-289596. According to this method, nucleic acids can be rapidly recovered by mixing a biological sample with a sufficient amount of a chaotropic agent (such as guanidinium salt) and silica beads and binding the free nucleic acids to a solid phase.
To obtain purified nucleic acids, however, this method requires a procedure for removing the guanidinium salt from the solid phase while retaining the nucleic acids bound to the solid phase, whereas a suitable removing procedure is not described.
For an efficient washing procedure of a solid phase at room temperature, the use of ethanol at least in a 75% concentration has been recommended in the past (C. W. Chen and C. A. Thomas, Jr., Anal. Biochem., 101,339-342(1980)). As ethanol is a volatile component, the mechanization of the method requires a close-open mechanism of a lid or a cooling mechanism for preventing ethanol from evaporation, and this invites upsizing of the device or deterioration of its reliability.
In addition, the method requires a washing step with 70% ethanol and/or acetone and hence requires a removing procedure of acetone by drying. When ethanol at a concentration of 70% or more and/or acetone, both of which are volatile, is mounted on an automatic device, the device requires a highly airtight chamber and a close-open mechanism of a lid and/or a cooling mechanism for preventing volatilization of the reagents, as described above.
The use of acetone has possibilities of dissolving plastics of a device employed for the recovery of nucleic acids and deteriorating the device due to its strong properties as an organic solvent, as mentioned above.
Therefore, materials of the device, cases and dispensers or other utensils to be used are remarkably limited. In addition, as acetone has acute toxicity and is inflammable, the release of acetone into the environment accompanied with the evaporation procedure should be avoided completely.
Japanese Unexamined Patent Publication No. 63-154696 discloses a method of isolating and purifying nucleic acids from an aqueous solution of a biological sample containing nucleic acids.
According to this method, an objective nucleic acid is recovered in the following manner: Initially, a biological sample is charged to a column filled with an anion exchanger, and the column is washed with an aqueous solution of sodium chloride to avoid the elution of an objective nucleic acid and to cleanse nonbinding components inclusive of carboxylated mucopolysaccharides. The objective nucleic acid is then recovered by eluting from the column with an aqueous solution of sodium chloride at such a concentration as to elute the objective nucleic acid.
The method just mentioned above ensures the recovery of an objective nucleic acid without using harmful substances.
This method where a sodium chloride aqueous solution is used as a washing solution, however, provides only a low recovery of nucleic acids. Accordingly, demands have been made to provide a method for recovering nucleic acids at a higher recovery yield.
To overcome the use of organic solvents in fractionating a nucleic acid, a method for the separation of nucleic acids is known in which a water-insoluble hybrid-forming carrier is supported on the surfaces of non-porous particles of 0.01-50 pm in particle diameter, the carrier having a single-chain nucleic acid bonded at least partly thereto (Japanese Unexamined Patent Publication No. 63-117262).
In the method disclosed by this publication, the carrier capable of hybridization with a nucleic acid is brought into contact with a nucleic acid-containing solution so that the hybridized carrier can be separated from that solution with no need for organic solvents. Separation of the carrier from the solution, however, needs a centrifugation step with eventual difficulty in attaining automation.
A method for the recovery of nucleic acids is also known in which cellulose or the like is fixed to have nucleic acid sequence that is partially compensatory for base sequence of an objective nucleic acid, followed by column-chromatographic recovery of the objective nucleic acid (Molecular Cloning: a laboratory manualxe2x80x942nd Ed., Cold Spring Harbor Laboratory Press (1989)).
In such instance, however, the use of column chromatography has the drawback that it causes poor efficiency when utilizing gravity drop, entailing large-scale apparatus since the system needs arrangement of pumps and the like.
Alternatively, as another conventional means evolved to omit a separation step, there may be applied a separating technique of B/F (bond form/free form) in which an antigen-antibody reaction is utilized with the use of an immunity analysis apparatus.
This technique is suitably useful for the case where probe chips are used, as a sample, which are provided with shoulders and with a resin having an antibody bonded physically or chemically thereto and filled between the shoulders (Japanese Unexamined Patent Publication No. 63-88456). Such conventional art, though excellent, is defective in that the probe chip sample is extremely difficult to form because it is necessary to encapsulate the resin between the shoulders.
A method for the recovery of nucleic acids without use of organic solvents is further known in which a nucleic acid is recovered by subjecting of the latter to non-specific bonding to silica in the presence of a chaotropic agent. However, this method fails to recover a nucleic acid by means of specific sequencing.
It is, therefore, an object of the present invention to provide a method and apparatus for the recovery of nucleic acids from a material containing nucleic acids, by which nucleic acids can be recovered rapidly and easily at a high recovery and high purity without deteriorating the yield.
It is another object of the invention to provide a method for the recovery of nucleic acids, which is suitable for apparatus for the automatic recovery of nucleic acids from a biological sample at a high recovery yield.
A further object of the invention is to provide a method for the recovery of nucleic acids, which is suitable for apparatus for the automatic recovery of plasmid DNAs from E. coli at a high recovery.
Still another object of the invention is to provide a method for and an apparatus for the recovery of nucleic acids which are speedy, simple and inexpensive to recover a highly pure nucleic acid from nucleic acid-containing materials and which are capable of automatically recovering nucleic acid components of specific sequences present in biological samples.
To achieve the above objects, the present invention provides the following constructions.
(1) The invention provides, in a first aspect, a method for the recovery of nucleic acids comprising a step 2 for mixing an accelerator substance for the binding of nucleic acids to a solid phase with a nucleic acid-containing material, a step 3 for making the mixture obtained in step 2 in contact with a solid phase bondable to nucleic acids to form a nucleic acid-binding solid phase, a step 4 for isolating the nucleic acid-binding solid phase from a liquid, a step 5 for washing the nucleic acid-binding solid phase with a solution containing an acetate, and a step 6 for eluting the nucleic acids from the solid phase.
(2) The method may preferably include a step 1 for promoting the release of nucleic acids from the nucleic acid-containing material before the step 2 in the above aspect.
(3) Step 5 in the above method may preferably be composed of a step 5a for removing non-nucleic-acid components from the nucleic acid-binding solid phase by washing, and a step 5b for removing the accelerator substance from the solid phase by washing.
(4) The substance for removing non-nucleic-acid components from the solid phase in step 5a may advantageously be guanidine hydrochloride.
(5) The acetate solution in the first aspect may preferably be a solution containing 0.5 mol/liter or more of potassium acetate.
(6) In a second aspect the invention provides a method for the recovery of nucleic acids from a material containing nucleic acids, which includes a step 2 for mixing an accelerator substance for the binding of nucleic acids to a solid phase with a nucleic acid-containing material, a step 3 for making the mixture obtained in the step 2 in contact with a solid phase bondable to nucleic acids to form a nucleic acid-binding solid phase, a step 4 for isolating the nucleic acid-binding solid phase from a liquid, a step 5 for washing the nucleic acid-binding solid phase with a solution containing 0.2 mol/liter or more of potassium chloride, and a step 6 for eluting the nucleic acids from the solid phase.
(7) The invention in a third aspect provides a method for the recovery of nucleic acids from a material containing nucleic acids, which is composed of a step 2 for mixing an accelerator substance for the binding of nucleic acids to a solid phase with a nucleic acid-containing material, a step 3 for making the mixture obtained in the step 2 in contact with a solid phase bondable to nucleic acids to form a nucleic acid-binding solid phase, a step 4 for isolating the nucleic acid-binding solid phase from a liquid, a step 5 for washing the nucleic acid-binding solid phase with a mixture of an aqueous solution of a salt and an alcohol, and a step 6 for eluting the nucleic acids from the solid phase.
(8) The method described in the third aspect may preferably have a step 7 for removing the alcohol after the elution of nucleic acids from the solid phase in step 6.
(9) The alcohol used in step 5 described in the third aspect may preferably be ethanol at a concentration of less than 50% in the mixture.
(10) The washing solution in step 5 described in the third aspect may advantageously be a solution containing 40% of ethanol and 10 mmol/liter or more of potassium acetate.
(11) The washing solution used in step 5 described in the third aspect may be a solution containing 40% of ethanol and 25 mmol/liter or more of sodium chloride.
(12) The accelerator substance used in step 2 in the above aspects may preferably be guanidine hydrochloride.
(13) Preferably, the solid phase bondable to nucleic acids may be a substance containing silicon dioxide.
(14) In a further aspect, the invention provides apparatus for the recovery of nucleic acids from a material containing nucleic acids, which is composed of a first means for mixing nucleic acids with an accelerator substance for the binding of nucleic acids to a solid phase, a second means for making the mixture in contact with a solid phase bondable to nucleic acids to form a nucleic acid-binding solid phase, a third means for isolating the nucleic acid-binding solid phase from a liquid, a fourth means for washing the nucleic acid-binding solid phase with a solution containing an acetate, and a fifth means for eluting the nucleic acids from the solid phase.
(15) The invention provides in yet another aspect apparatus for the recovery of nucleic acids from a material containing nucleic acids, which is composed of: a first pipetter for discharging an accelerator substance for the binding of nucleic acids to a solid phase, a solid phase bondable to nucleic acids, a washing solution for removing the accelerator substance from the solid phase, and a liquid for eluting nucleic acids from the solid phase, separately and in turn, into a chamber encasing a nucleic acid-containing material and for stirring the liquid mixture in the chamber, an isolating means for isolating the solid phase from the liquid phase in the chamber, a second pipetter for aspirating the liquid phase isolated by the isolating means from the chamber, and a control means for controlling operations of the first pipetter, the isolating means and the second pipetter, wherein the liquid which has been eluted from the solid phase by an eluent for eluting nucleic acids and isolated by the isolating means as a liquid phase is aspirated by the second pipetter, and an aqueous solution containing the nucleic acids is purified from the aspirated liquid.
When guanidine hydrochloride (hereinafter briefly referred to as GuHCl) is used as the accelerator substance for the binding of nucleic acids to a solid phase in step 1 of the above methods, such effects on absorbance at 260 nm as to adversely affect the assay of the purity or quantity of nucleic acids can be markedly reduced.
As the solid phase bondable to nucleic acids in step 2, any substance containing silicon oxide such as glass beads, silica powder, quartz filter paper, quartz wool or crushed products of these substances, diatomaceous earth and the like can be employed. When the solid phase has a particle size ranging from about 1 to about 100 xcexcm, a practically sufficient binding of nucleic acids to the solid phase can be obtained in several minutes to ten minutes.
The use of diatomaceous earth can reduce a cost necessary for one treatment. When a stirring procedure is also employed for enhancing the contact probability of nucleic acid and the solid phase while depending on the specific gravity of the particle to be used, the reaction time for binding can be shortened and the reproducibility can be enhanced.
A bond form/free form isolation (B/F isolation) technique generally used in immunoassay devices utilizing an antigen-antibody reaction can be used as the isolating means for isolating the solid phase from a liquid in step 3, and known technologies in immunoassay devices can be exploited.
The step for washing the nucleic acid-binding solid phase with a solution containing an acetate or potassium chloride, or a mixture of an aqueous solution of a salt and an alcohol in step 4 can provide washing of the solid phase while maintaining the binding of nucleic acids to the solid phase. Accordingly, contaminants can be removed at a practically sufficient level without cooling when step 4 is divided into step 4a and step 4b, using GuHCl as the washing solution in step 4a and using a 40% ethanol aqueous solution containing 10 mmol/liter or more of potassium acetate as the washing solution in step 4b.
When a solution containing an alcohol is employed in step 4b, the addition of step 6 for removing the alcohol component after step 5 can prevent the contamination of alcoh in a final purified solution of nucleic acids.
According to a further aspect of the present invention, there is provided a method for and an apparatus for the recovering nucleic acids which enable a nucleic acid to be speedily simply recovered, with high purity and low cost, from materials containing nucleic acids and which enable nucleic acid components of specific sequence to be automatically recovered from biological samples. This aspect can be achieved by the following characteristics.
In the method of the present invention, a nucleic acid is recoverable by bringing a nucleic acid component-containing solution into contact in a pipeline with a solid phase bondable to the nucleic acid component. More specifically, this method comprises: a first step in which a mixed solution is prepared, the mixed solution being composed of a solution containing an objective nucleic acid component having a specific sequence and distributed in containers and an accelerator substance placed in the containers and acting to accelerate bonding of the nucleic acid component to a solid phase bondable to the latter component; a second step in which the mixed solution is contacted with the solid phase disposed in a pipeline by suctioning the mixed solution in the pipeline; a third step in which the solid phase is separated from a non-bondable component having not bonded thereto by discharging the mixed solution from the pipeline; a fourth step in which the solid phase is washed by suctioning a washing solution in the pipeline and then discharging the same therefrom; and a fifth step in which a nucleic acid component of a specific sequence is eluted from the solid phase by suctioning an eluting solution in the pipeline and then discharging the same therefrom.

Apparatus for the recovery of nucleic acids


A portable telephone includes a telephone body containing telephone circuitry, a rechargeable cell, and a power generation device having a magnet structure, a coil, and a rectifier for generating a direct current (D.C.) voltage to charge the rechargeable cell. The magnet structure may be an armature and the coil may be fixed, or the magnet structure may be a stator and the coil may be movable. The magnet structure may be a multiple pole magnet made up of a plurality of individual pole structures, each pole structure including a pair of magnets joined to each other with facing poles of like polarity. In addition, the coil may include clockwise and counterclockwise windings arranged in a multi-layered stacked arrangement.

1. Field of the Invention
This invention relates to a self-rechargeable portable telephone, and more particularly to a self-rechargeable portable telephone/handset having a power generation device capable of converting mechanical energy resulting from movement of the telephone into electric energy and storing the electric energy in a battery cell.
In a preferred embodiment of the invention, the power generation device of the portable electric telephone includes a power generation device of the type described in copending parent U.S. patent application Ser. No. 10/170,717, including a fixed or movable coil, a corresponding movable or fixed magnet structure, a rectifier, and at least one of the following additional features:                A. The magnet structure including a series of N-S-N-S poles constructed using a novel joining method that overcomes problems of high remanance and coercivity, and thereby increases flux density;        B. The stationary or movable coil including windings constructed using a novel winding method that results in maximum magnetic lines cutting in linear motion.
2. Description of Related Art
Typically, portable telephones used for wired and wireless communications employ a disposal non-rechargeable primary cell or a rechargeable secondary cell that must be recharged through an external charging device.
In copending U.S. patent application Ser. No. 10/170,717, it was proposed to provide a portable telephone having an internal generator arranged to provide charging current to a secondary cell upon movement of the telephone, thereby enabling the use of environmentally-friendly secondary cells without the need for an external charging device. In addition to eliminating the inconvenience of battery. disposal or charging, the proposed portable telephone offered advantages of energy conservation and pollution reduction due to elimination of the need to draw charging power from the public power grid.
Although showing great promise, a problem with implementation of the self-rechargeable telephone has been the relatively low magnetic efficiency of suitable sized and priced magnets and coils, which typically have a relatively low flux density and/or provide an inefficient distribution of magnetic lines. Although more efficient magnets or magnet structures are known, such as the rare earth magnets disclosed in U.S. Pat. Nos. 5,347,186 and 5,818,132; the composite armature and multiple coil structure of U.S. Pat. No. 4,500,827; the wound magnetic core disclosed in U.S. Pat. No. 4,709,176; or the composite coil and stack neodymium disc magnets disclosed in U.S. Pat. No. 5,975,714, they are generally expensive to manufacture and/or too large for the applications mentioned above. Further, while distribution of magnetic lines from a coil can be improved by adding a permeable material to the coil structure, the permeable material has the disadvantage not only of adding to the complexity of the structure, but also to the diamagnetic resistance effect.


The present invention is directed to a collapsible combined table and dolly that is portable and capable of securely transporting items of various sizes and configurations. The collapsible combined table and dolly provides ease of operation through a collapsible/expandable table top and convenient means for transporting and storing items for use in the display/workspace of the table.

The field of the invention is generally related to a multi-purpose portable table and hand truck or dolly of the type used for displaying and transporting items.
Multi-purpose portable tables are often utilized for both indoor and outdoor activities to provide support for displaying items or a work/play space for a wide variety of activities. However, the term "portable table" is often relative because many such tables though movable and transportable are, in fact, very difficult to transport. In addition, even when the portable table is amenable to being transported, the user often must make several trips from their original location to their destination in order to separately and individually transport items that are to be located on the workspace of the table. In order to overcome these shortcomings, background art portable tables have often been enhanced by being equipped with wheels and base plates that facilitate transporting the portable table and moving items to be used in the workspace of the table. However, further enhancements of portable tables could provide an even more user friendly portable table apparatus.
Some examples of background art in this field of invention include U.S. Pat. Nos. 4,565,382 and 4,934,718. The 382' patent is a combined portable table top 11 and hand truck 10 with an open-sided load supporting rack 28 for transporting items and with retaining means 32 for controlling the items being transported. The 718' patent is a multi-purpose hand truck 1 having an open-sided toe plate 7 for transporting items and a table top 10 for a workspace. However, the open-sided nature of the plate for transporting items of the hand trucks of the 718' and 382' patents do not allow the hand trucks of these patents to be effective for carrying small items that can not be easily restrained or that may roll and thus, need to be contained while in transport.
Other examples of the background art in this field of invention include U.S. Pat. Nos. 3,064,989 and 5,161,811. The 989' patent is a wheeled dolly 10 with a foldable supporting frame 6 having an open-sided support member 19 for transporting items when used as a dolly/hand truck. The 811' patent is a trolley/hand truck with a foldable seat 22 instead of a table top and a support frame 13 that, as in the 989' patent, provides an open-side support member for transporting items when used as a hand truck. In addition, both the wheeled dolly of the 989' patent and the trolley/hand truck of the 811' patent provide a minimal amount of supporting surface (i.e., merely the support frame members) behind the items being transported when used as a hand truck. Thus, the 989' and 811' patents have the same shortcomings as the 382' and 718' patents discussed above and additional disadvantages with regard to the limited amount of supporting surface available for use when transporting items.
Yet other examples of the background art in this field of invention include U.S. Pat. Nos. 5,957,472 and 6,371,495. The 472' patent is an apparatus 10 forming a combined hand truck and table top/machine support 16. The combined hand truck and table top of the 472' patent includes an open-sided base plate 34 for transporting items, and thus, the 472' patent has the same shortcomings as the 382', 718' and 811' patents discussed above.
The 495' patent is a table frame 60 with fold out legs 40 and a trolley 30 with a support plate 90. In contrast to the above discussed patents, support plate 90 further includes support blocks 92 which partially enclose the sides of the support plate 90. However, the 495' patent is still not effective for transporting small items that can not be easily restrained or that may roll between the openings in the support blocks.
Therefore, there is a need in the art for a combined multi-purpose portable combined table and dolly/hand truck that can be easily set-up; and conveniently move and securely transport items of various shapes, sizes and configurations from one location to another.

Apparatus for a collapsible table and dolly


A fluorescent material is described which remains uninfluenced in the presence of oxygen during fabrication, allows a highly efficient light emission due to the concentration of donors being adjustable as appropriate, and is excellent in giving a bright light and having a long life. The fluorescent material is represented by the formula Ga.sub.1-x In.sub.x N:M,X, wherein 0.ltoreq.x<0.8, M is at least one element selected from the group of Be, Mg, Ca, Sr, Ba, Zn, Cd and Hg, and X is at least one element selected from the group of C, Si, Ge, Sn and Pb. The fluorescent material preferably has concentration ranges (mol %) of the elements M and X of 0.005<M<0.7 and 0.002<X<0.8. The starting materials utilized for preparing the fluorescent material are substances devoid of oxygen, preferably (SiH.sub.a N.sub.b).sub.n where a=1-3, b=0 or 1, and n=an integer of 1 or more.

1. Field of the Invention
This invention relates to a fluorescent material which is produced after a solid solution comprising gallium nitride and indium nitride have been doped with a doping substance, or to a fluorescent material which emits light by electron beam excitation, has a property to emit light different in color according to what materials are chosen for the constituents, and has an excellently long life.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. 51-41686 discloses a fluorescent material which is produced after Ga.sub.2 O.sub.3 has been nitrified in an atmosphere of ammonia to produce GaN, and then GaN, being made as a substrate, has been doped with Cd a dopant. This fluorescent material is not applied, however, for the purpose of light emission by electron beam excitation, and the said reference does not give any mention of the method how to use the fluorescent material to emit light by electron beam excitation.
When Ga.sub.2 O.sub.3 is nitrified in an atmosphere of nitrogen, nitrification of Ga.sub.2 O.sub.3 starts from the surface. When the system is heated to a high temperature, the nitrified surface is oxidized again. Namely, gallium nitride has a tendency to easily lose nitrogen. This is the reason why Ga.sub.2 O.sub.3 becomes an n type, has a very low resistance and emits light even when not doped.
Emission of light from gallium nitride occurs as a result of the pairing between donors (D) and acceptors (A). Acceptors are formed after Zn, Mg, etc. are added. Donors are nitrogen deficits naturally produced. When a conventional procedure is used for increasing the concentration of donors, it results in the increase of nitrogen deficits of the material, which will degrade the crystal regularity of the material. As seen from this, with gallium nitride produced by a conventional procedure, it is impossible to adjust the number of donors to a desired value.
Further, gallium nitride has a possibility of being oxidized in the presence of oxygen. Accordingly, if Ga.sub.2 O.sub.3 or an oxide is used as a starting material, it is quite difficult to convert it completely into a nitride compound. Even if this is feasible, the resulting gallium nitride will be inferior in quality because residual oxygen therein will have an adverse effect on light emission.


A wide-range compatible switching power supply circuit employs switching frequency varying control and allows enhancement of its AC to DC power conversion efficiency when a large AC input voltage is used. A coupled resonant circuit employing electromagnetic coupling by an isolation converter transformer is formed by providing a series resonant circuit both on the primary side and on the secondary side of the transformer. In order to achieve a unimodal output characteristic in the coupled resonant circuit, the length of a gap formed in a core of the isolation converter transformer is set to about 2.0 mm, and a coupling coefficient is set to about 0.8 or less. Thus, the switching frequency variable control range can be narrowed, which allows a wide-range compatible configuration. In addition, resonant frequencies of primary-side and secondary-side resonant circuits are set so that a requisite phase shift arises between a primary-side series resonant current and a secondary-side rectified current at least when an AC input voltage is 100 V and the load power is the maximum load power. Thus, the AC to DC power conversion efficiency when the AC input voltage VAC is 230 V can be enhanced.

The present invention relates to a switching power supply circuit included in various electronic apparatuses as a power supply.
The present assignee has proposed various power supply circuits including a resonant converter on the primary side thereof. Japanese Patent Laid-open No. 2003-235259 discloses one example of the proposed power supply circuits.
FIG. 12 is a circuit diagram illustrating one example of a switching power supply circuit that includes a resonant converter and is constructed based on any of the inventions that have been filed by the present assignee.
The switching converter in the power supply circuit shown in FIG. 12 has a configuration in which a separately-excited current resonant converter constructed by half-bridge connection is combined with a partial voltage resonant circuit that performs voltage resonant operation only at the time of turn-off in the switching.
In the power supply circuit in FIG. 12, coupled to a commercial alternating-current power supply AC is a common mode noise filter formed of two filter capacitors CL and one common mode choke coil CMC.
As a rectifying and smoothing circuit for producing a DC input voltage from an AC input voltage VAC from the commercial power supply AC, a full-wave rectifier circuit formed of a bridge rectifier circuit Di and a smoothing capacitor Ci are provided downstream from the common mode noise filter.
The rectified output from the bridge rectifier circuit Di is charged in the smoothing capacitor Ci, and thus obtained across the smoothing capacitor Ci is a rectified and smoothed voltage Ei (DC input voltage) with the same level as that of the AC input voltage VAC.
As a current resonant converter that is fed with the DC input voltage and implements switching, a switching circuit system is provided in which two switching elements Q1 and Q2 formed of MOS-FETs are connected to each other by half-bridge connection as shown in the drawing. Damper diodes DD1 and DD2 formed of body diodes are connected in parallel with the channel between the drain and source of the switching elements Q1 and Q2, respectively, with having the anode-to-cathode direction indicated in the drawing.
In addition, a partial resonant capacitor Cp is connected in parallel with the channel between the drain and source of the switching element Q2. The capacitance of the partial resonant capacitor Cp and a leakage inductance L1 of a primary winding N1 form a parallel resonant circuit (partial voltage resonant circuit). This partial voltage resonant circuit allows partial voltage resonant operation in which voltage resonance arises only when the switching elements Q1 and Q2 are turned off.
The power supply circuit is provided with an oscillation and drive circuit 2 formed of e.g. general-purpose ICs in order to switching-drive the switching elements Q1 and Q2. The oscillation and drive circuit 2 includes an oscillation circuit and a drive circuit, and applies a drive signal (gate voltage) with a requisite frequency to the gates of the switching elements Q1 and Q2. Thus, the switching elements Q1 and Q2 implement switching operation so that they are alternately turned on/off with the requisite switching frequency.
An isolation converter transformer PIT (Power Isolation Transformer) transmits switching outputs from the switching elements Q1 and Q2 to the secondary side.
One end of the primary winding N1 in the isolation converter transformer PIT is coupled via a primary-side series resonant capacitor C1 to the connecting node (switching output node) between the source of the switching element Q1 and the drain of the switching element Q2, which allows acquisition of the switching outputs.
The other end of the primary winding N1 is connected to the primary-side ground as shown in the drawing.
The series resonant capacitor C1 and the primary winding N1 are connected in series. The capacitance of the series resonant capacitor C1 and the leakage inductance L1 of the primary winding N1 (series resonant winding) in the isolation converter transformer PIT form a primary-side series resonant circuit that offers current resonant operation as the operation of the switching converter.
According to the above description, the primary-side switching converter shown in FIG. 12 offers current resonant operation by the primary-side series resonant circuit (L1-C1) and partial voltage resonant operation by the above-described partial voltage resonant circuit (Cp//L1).
That is, the power supply circuit shown in the drawing employs a configuration in which a resonant circuit that offers a resonant converter as the primary-side switching converter is combined with another resonant circuit. Hereinafter, such a switching converter is referred to as a complex resonant converter.
The isolation converter transformer PIT is constructed of an EE-core that is formed by combining E-cores composed of a ferrite material for example, although the illustration thereof in this drawing is omitted. Furthermore, the primary winding N1 and a secondary winding N2 are wound around the center magnetic leg of the EE-core, with the winding part being divided into the primary side and secondary side.
In addition, a gap with a gap length of 1.0 mm or smaller is provided in the center leg of the EE-core in the isolation converter transformer PIT, so that a coupling coefficient of about 0.80 to 0.90 is obtained between the primary winding N1 and the secondary winding N2.
In practice, a coupling coefficient k of about 0.85 is obtained under the following conditions: a gap G is about 0.8 mm, and the numbers of turns of the primary winding N1 and the secondary winding N2 are 20 T (turn) and 50 T (25 T+25 T), respectively.
The secondary winding N2 in the isolation converter transformer PIT is provided with a center tap connected to the secondary-side ground as shown in the drawing, which divides the secondary winding N2 into a secondary winding portion N2A and a secondary winding portion N2B. In addition, rectifier diodes Do1 and Do2 are connected in series to the secondary winding portion N2A and the secondary winding portion N2B, respectively, and a smoothing capacitor Co for smoothing a rectified output from the rectifier diodes Do1 and Do2 is provided. Thus, a full-wave center-tap rectifier circuit is achieved.
Accordingly, as a voltage across the smoothing capacitor Co, a secondary-side DC output voltage Eo is obtained that is a DC voltage with the same level as that of an alternating voltage induced in each secondary winding portion. The secondary-side DC output voltage Eo is supplied to a main load (not shown) as a main DC voltage, and is branched and input to a control circuit 1 as a detected voltage for constant-voltage control.
The control circuit 1 outputs to the oscillation and drive circuit 2 a control signal as a voltage or current of which level is varied depending on the level of the secondary-side DC output voltage Eo.
Based on the control signal input from the control circuit 1, the oscillation and drive circuit 2 varies the frequency of an oscillation signal generated by the oscillation circuit in the oscillation and drive circuit 2, to thereby change the frequency of a switching drive signal applied to the gates of the switching elements Q1 and Q2. Thus, the switching frequency is varied. If the switching frequency of the switching elements Q1 and Q2 is thus varied depending on the level of the secondary-side DC output voltage Eo, the resonant impedance of the primary-side series resonant circuit changes and therefore energy is also changed that is transmitted from the primary winding N1, which forms the primary-side series resonant circuit, to the secondary side. Accordingly, the level of the secondary-side DC output voltage Eo is also varied. Thus, constant-voltage control for the secondary-side DC output voltage Eo is achieved.
Hereinafter, such a constant-voltage control method in which the switching frequency is varied for stabilizing the output voltage is referred to as a switching frequency control method.
FIG. 13 is a waveform diagram for showing the operations of major parts in the power supply circuit of FIG. 12. This diagram shows the operations when the load power Po is 200 W and 0 W, respectively, in the circuit shown in FIG. 12. It should be noted that the load power Po of 200 W is the maximum load power (Pomax) of the circuit in FIG. 12, and 0 W is the minimum load power (Pomin).
Furthermore, in FIG. 13, the AC input voltage VAC is kept constant at 100 V as the input voltage condition. As the secondary-side DC output voltage Eo, a voltage of 100 V or larger is produced.
In order to achieve the above-described conditions of the load power, input voltage and secondary-side DC output voltage, elements having the following characteristics are selected as the major parts in the circuit in FIG. 12:                the isolation converter transformer PIT having a gap length of 0.8 mm and a coupling coefficient k of about 0.85        the primary winding N1 of which number of turns is 20 T        the secondary winding N2 of which number of turns is 50 T (25 T+25 T, across the center tap)        the primary-side series resonant capacitor C1 having a capacitance of 0.068 μF and        the partial resonant capacitor Cp having a capacitance of 1000 pF.
Referring to FIG. 13, a rectangular waveform voltage V1 is a voltage across the switching element Q2, and indicates the on/off timings of the switching element Q2.
The period during which the voltage V1 is at the 0 level corresponds to the on-period during which the switching element Q2 is in the on-state. In this on-period, a switching current IQ2 having the illustrated waveform flows through the switching circuit system composed of the switching element Q2 and the clamp diode DD2. In contrast, the period during which the voltage V1 is clamped at the level of the rectified and smoothed voltage Ei corresponds to the period during which the switching element Q2 is in the off-state. In this off-period, the switching current IQ2 is at the 0 level as shown in FIG. 13.
In addition, although not illustrated, a voltage across the other switching element Q1 and a switching current flowing in the other switching circuit system (Q1, DD1) have a waveform obtained by shifting by 180° the phase of the waveform of the voltage V1 and the switching current IQ2, respectively. That is, as described above, the switching elements Q1 and Q2 implement switching operation with timings at which they are alternately turned on/off.
A primary-side series resonant current Io (not shown) flows through the primary-side series resonant circuit (C1-N1(L1)) with having a waveform resulting from synthesis of the waveforms of the switching currents flowing in these switching circuits (Q1, DD1) and (Q2, DD2).
A comparison between the waveform of the voltage V1 when the load power Po is 200 W and that when it is 0 W makes it apparent that the switching frequency of the primary side is controlled so that the switching frequency be lower when the secondary-side DC output voltage Eo is supplied to a heavier load (Po=200 W) than that when it is supplied to a lighter load (Po=0 W). Specifically, in response to lowering of the level of the secondary-side DC output voltage Eo due to a heavy load, the switching frequency is decreased. In contrast, in response to a rise of the level of the secondary-side DC output voltage Eo due to a light load, the switching frequency is increased. Such switching frequency changes indicate the fact that constant-voltage control operation by upper-side control is carried out as the switching frequency control method.
In this power supply circuit, as shown in FIG. 13, the peak level of the switching current IQ2 when the load power Po is 200 W is 5.6 Ap while that when the load power Po is 0 W is 0.8 Ap.
The above-described operation on the primary side induces an alternating voltage V2 having the illustrated waveform in the secondary winding N2 of the isolation converter transformer PIT. In the half cycles during which the alternating voltage V2 is positive, a current flows through the rectifier diode Do1 on the secondary side. In contrast, in the half cycles during which the alternating voltage V2 is negative (i.e., the half cycles during which an alternating voltage excited in the secondary winding portion N2B is positive), a current flows through the rectifier diode Do2. Thus, in the full-wave center-tap rectifier circuit on the secondary side, a rectified output current I2 flowing between the center tap of the secondary winding N2 and the secondary-side ground has a waveform of which peak levels appear with the same cycle as that with which the positive and negative peak levels of the alternating voltage V2 appear as shown in FIG. 13.
The peak level of the alternating voltage V2 is equal to the level of the secondary-side DC output voltage Eo. In FIG. 13, the peak levels of the rectified output current I2 in the respective half cycles are different: 3 Ap and 2 Ap. The reason for this will be described later.
When a resonant converter configuration is adopted that stabilizes the secondary-side DC output voltage with a switching frequency control method like the power supply circuit in FIG. 12, there is a tendency that the variable control range of the switching frequency for stabilization is a comparatively wide range.
This respect will be with reference to FIG. 14. FIG. 14 shows the constant-voltage control characteristic of a conventional power supply circuit that employs a switching frequency control method for stabilizing its output voltage. The characteristic is indicated as the relationship between a switching frequency fs and the level of the secondary-side DC output voltage Eo.
The following description for this diagram is based on the premise that the power supply circuit of FIG. 12 employs a so-called upper-side control method as a switching frequency control method. The term upper-side control refers to a control method in which the switching frequency is changed within a range of frequencies higher than a resonant frequency fo of the primary-side series resonant circuit, and a resonant impedance change arising from the switching frequency change is utilized to control the level of the secondary-side DC output voltage Eo.
In general, the resonant impedance of a series resonant circuit becomes lowest when the frequency is the resonant frequency fo. Accordingly, the relationship between the secondary-side DC output voltage Eo and the switching frequency fs in the upper-side control is as follows: a switching frequency fs closer to the resonant frequency fo leads to a higher level of the secondary-side DC output voltage Eo while one remoter from the resonant frequency fo leads to a lower level.
Therefore, under the condition that the load power Po is constant, the function of level of the secondary-side DC output voltage Eo depending on the switching frequency fs draws a quadratic curve in which its peak appears when the switching frequency fs is the same as the resonant frequency fo of the primary-side series resonant circuit, and the level decreases as the switching frequency fs is remoter from the resonant frequency fo.
In addition, for the same switching frequency fs, the level of the secondary-side DC output voltage Eo is different depending on the load power Po. Specifically, the voltage level when the load power is the maximum load power Pomax is lower by a certain value than that when the load power is the minimum load power Pomin. That is, under the condition that the switching frequency fs is fixed, a heavier load results in a lower level of the secondary-side DC output voltage Eo.
When it is aimed to, under such a characteristic, stabilize the secondary-side DC output voltage Eo at a voltage level tg by upper-side control, the requisite variable range (requisite control range) of the switching frequency is a range indicated by Δfs.
In an actual power supply circuit shown in FIG. 12, for example, constant-voltage control is implemented so that the secondary-side DC output voltage Eo is stabilized at 135 V by a switching frequency control method, under the following conditions: an input variation range of 85 V to 120 V of the AC input voltage VAC as an AC 100 V-system input; and the maximum and minimum load powers Pomax and Pomin of 200 W and 0 W (no load), respectively, of the secondary-side DC output voltage Eo, which is a main DC voltage.
Under these conditions, the variable range of the switching frequency fs required for constant-voltage control in a conventional typical power supply circuit is from about 80 kHz to about 200 kHz or higher, i.e., Δfs is 120 kHz or higher. This range is considerably wide.
As a power supply circuit, a so-called wide-range compatible one is known that can operate compatibly with an AC input voltage range of 85 V to 288 V for example, so that it can be used both in areas employing the input voltage AC 100 V-system such as Japan and the United States and in areas employing the AC 200 V-system such as Europe.
Consideration will be made below as to provision of a wide-range compatible configuration for a conventional power supply circuit that implements switching frequency control, typified by the power supply circuit in FIG. 12.
The wide-range compatible circuit can accept an AC input voltage range of 85 V to 288 V for example as described above. Therefore, compared with a single-range compatible one that can accept either one of the AC 100 V-system and the AC 200 V-system for example, the level variation range of the secondary-side DC output voltage Eo is larger. In order to implement constant-voltage control for the secondary-side DC output voltage Eo of which level variation range is wide due to such a wide AC input voltage range, a wide switching frequency control range is required. If a conventional power supply circuit has a switching frequency control range of 80 kHz to 200 kHz for an AC 100 V-system single range as described above, in order for the power supply circuit to have a wide-range compatible configuration, the switching frequency control range needs to be widened to a range of about 80 kHz to 500 kHz.
However, in a present IC (the oscillation and drive circuit 2) for driving switching elements, the upper limit of a possible drive frequency is about 200 kHz. Even if a switching drive IC capable of driving elements with the above-described high frequency can be formed and mounted, driving of switching elements with such a high frequency leads to a significantly low power conversion efficiency, and therefore this IC is impractical in an actual power supply circuit.
Accordingly, it has been thought that it is very difficult to achieve a wide-range compatible configuration in a conventional power supply circuit only by stabilizing operation by a switching frequency control method.
In addition, if the power supply circuit includes a full-wave center-tap rectifier circuit as its secondary-side rectifier circuit like one shown in FIG. 12, the switching frequency control range is further widened in particular.
In the full-wave center-tap rectifier circuit, the secondary winding N2 is center-tapped, and thus two secondary winding portions (N2A, N2B) are formed. In these two secondary winding portions N2A and N2B, in the periods of half cycles of one polarity (hereinafter, one half cycles) of an alternating voltage excited in the secondary winding N2, a rectified current flows through the secondary winding portion N2A, the rectifier diode Do1, the smoothing capacitor Co, and the secondary winding portion N2A in that order. In contrast, in the periods of half cycles of the other polarity (hereinafter, the other half cycles) of the alternating voltage, a rectified current flows through the secondary winding portion N2B, the rectifier diode Do2, the smoothing capacitor Co, and the secondary winding portion N2B in that order.
That is, in full-wave center-tap rectification, in the periods of one half cycles, a current flows through only one of the two secondary winding portions but does not flow through the other winding portion.
In such full-wave center-tap rectifying operation, a given electrostatic capacitance exists between the secondary winding portion N2A and the secondary winding portion N2B, which are each wound around a bobbin in the isolation converter transformer PIT.
The existence of the interwinding capacitance is equivalent to the state in which a capacitor Cp20 is connected in parallel with the secondary winding N2 on the secondary side of the isolation converter transformer PIT as shown in FIG. 12.
The connecting of the capacitor Cp20 in parallel with the secondary winding N2 results in formation of a parallel resonant circuit also on the secondary side, by the leakage inductance of the secondary winding N2 and the capacitance of the capacitor Cp20.
The capacitance of the capacitor Cp20 is determined depending on the number of strands in a litz line used for the secondary winding N2 and the window area of the bobbin around which the secondary winding N2 is wound. In the circuit of FIG. 12 involving the above-described conditions, this capacitance is about 100 pF to 500 pF, which is minute.
Since the parallel resonant circuit is thus formed also on the secondary side, an actual circuit of FIG. 12 involves, as a constant-voltage characteristic about the secondary-side DC output voltage Eo like that shown in FIG. 14, a characteristic shown in FIG. 15.
Referring to FIG. 15, in addition to a resonant frequency fo1 of the primary-side series resonant circuit, a resonant frequency fo2p of the secondary-side parallel resonant circuit exists since the parallel resonant circuit is formed also on the secondary side as described above.
When the load power is the minimum load power Pomin in particular, the existence of the different two resonant points results in, as a characteristic curve, a bimodal curve like the illustrated curve including two peaks: the peak corresponding to the primary-side resonant frequency fo1 and the peak corresponding to the secondary-side resonant frequency fo2p.
In this case, since the capacitance of the capacitor Cp20 is comparatively minute as described above, when there is a tendency toward a heavier load and thus the level of the secondary-side DC output voltage Eo is comparatively low, the secondary-side resonant point has no effect on the characteristic curve (see the characteristic curve when the load power is the maximum load power Pomax). However, when there arises a tendency toward a lighter heavy and thus the load state approaches no-load state, the level of the secondary-side DC output voltage Eo tends to sharply rise. This level rise yields a bimodal characteristic curve like the characteristic curve when the load power Po is 0 as the secondary-side resonant point is elicited.
A comparison between the bimodal characteristic curve and the characteristic curve in FIG. 14 when the load power Po is 0 W allows understanding of the tendency that, in the no-load state, the switching frequency in the bimodal curve of FIG. 15 is higher than that in a unimodal curve for the same output voltage level.
In addition, according to this tendency, the bimodal curve in FIG. 15 leads to a wider requisite control range Δfs of the switching frequency as is apparent from a comparison between two Δfs in FIGS. 14 and 15.
FIG. 16 is a diagram showing the variation characteristic of the switching frequency fs as a function of load in the circuit of FIG. 12, which includes a full-wave center-tap rectifier circuit as its secondary-side rectifier circuit.
According to this characteristic diagram, using a full-wave center-tap rectifier circuit leads to the tendency that the switching frequency sharply rises when the load power Po approaches 0 W due to the elicitation of the secondary-side resonant point as described above.
According to experiments, the switching frequency fs was about 75.8 kHz when the load power was the maximum load power Pomax. In contrast, when the load power was the minimum load power Pomin, the switching frequency fs rose to about 172.4 kHz.
As described above, if a full-wave center-tap rectifier circuit is formed on the secondary-side as a conventional power supply circuit configuration, the requisite control range Δfs is further widened since the existence of two resonant points due to the resonant circuits on the primary-side and secondary-side leads to the widening thereof.
This further widening of the requisite control range Δfs makes it almost impossible to achieve a wide-range compatible configuration.
Furthermore, a wide control range of the switching frequency also causes a problem that the high-speed response characteristic of stabilizing the secondary-side DC output voltage Eo is lowered.
Some electronic apparatuses involve operation in which the load condition varies in such a manner to be instantaneously switched between the maximum-load state and the almost-no-load state for example. Such load variation is referred to as switching load. A power supply circuit incorporated in such apparatuses needs to adequately stabilize its secondary-side DC output voltage even in response to the load variation called the switching load.
However, when the power supply circuit involves a wide control range of the switching frequency as described with reference to FIGS. 14 and 15, it takes a comparatively long time period for the circuit to vary its switching frequency to the frequency for achieving a requisite level of the secondary-side DC output voltage in response to load variation like the switching load. That is, an unfavorable result is obtained as the response characteristic of constant-voltage control.
In particular, the power supply circuit shown in FIG. 12 has such a switching frequency characteristic for constant-voltage control that the switching frequency greatly varies within a load power range of 0 W to about 25 W as shown in FIG. 16. This characteristic is disadvantageous as a constant-voltage control response characteristic against the switching load.
In addition, using a full-wave center-tap rectifier circuit as the secondary-side rectifier circuit like the circuit in FIG. 12 also leads to another problem that bias magnetization arises in the isolation converter transformer PIT in particular.
Specifically, of the secondary winding portions N2A and N2B, one winding portion is long while the other is short depending on which of two is first wound around the bobbin in the isolation converter transformer PIT. Due to this winding length difference, the coupling coefficient between the primary winding N1 and the secondary winding portion N2A is different from that between the primary winding N1 and the secondary winding portion N2B.
In an actual circuit of FIG. 12, the coupling coefficient k between the primary winding N1 and the secondary winding portion N2A is 0.86 while that between the primary winding N1 and the secondary winding portion N2B is 0.85. Thus, a difference arises between the leakage inductances of the respective winding portions. As a result, as shown in the waveform diagram of FIG. 13, the rectified output current I2 has a waveform in which peak levels in the respective half cycles are different from each other.
Since the peak levels of the rectified current in the respective half cycles are thus different, the peak levels of currents flowing through the rectifier diodes (Do1, Do2) on the secondary side are also different. As a result, the breakdown current level of one rectifier diode needs to be increased compared with the case in which rectified currents having the same peak level flow through the respective diodes. Therefore, a need arises to select a more expensive part with a higher breakdown current level than a part used when rectified currents have the same peak level, which imposes cost-up of fabrication of the power supply circuit.
In addition, the different peak levels of rectified currents also cause a problem that a bias arises between conductive losses in the rectifier diodes Do1 and Do2.
Actual experiments on the power supply circuit shown in FIG. 12 revealed that the AC to DC power conversion efficiency ηAC→DC was about 90.5% when the AC input voltage VAC was 100 V and the load power Po was 200 W. Moreover, the experiments offered a result that an AC input power Pin was about 2.6 W when the load power Po was 0 W.


An automated system for partitioning a set of Boolean logic equations onto one or more devices selected from a plurality of commercially available devices. The system utilizes a processor having a memory containing information on the different architectural types of devices, physical device information on individual devices and user generated design constraints, weighting factors and partitioning directives. Based upon this stored information, the system of the present invention selects all acceptable architectural types of devices wherein at least one of the Boolean logic equations can be placed thereon. For all physical devices associated with the acceptable architectural types only those devices which fall within the selected user constraints are selected. The system then evaluates the weighting factors to order the devices in order of cost value and then fits the equations according to the partitioning directives to the devices. During the fitting process, an optimum device solution is attained having a least cost value for which the system produces an output map suitable for the user of the system to configure the selected devices to implement the set of equations.

1. Related Invention
The present invention is related to "Digital Waveform Analyzer", filed Jan. 11, 1988, Ser. No. 07/142,652, now Pat. No. 4,873,647.
2. Field of the Invention
The present invention relates in general to a method and apparatus for partitioning Boolean equations representative of logical relationships between input and output digital signals for implementation into actual physical logic devices. More particularly, the present invention relates to a method and apparatus for performing partitioning of Boolean logic equations based upon user generated cost values, physical constraints, and pin directives into actual physical devices wherein a plurality of possible partitioning solutions are tabulated in order of cost value.
3. Statement of the Problem
In the design of digital systems, a problem exists with the incompatibility of the various components available from different manufacturers. For example, the manufacturer of a computer will specify the various input and output binary signals necessary to communicate with its computer. Likewise, the manufacturers of the peripheral devices that interconnect with the computer also provide detailed signal specifications for interconnecting the inputs and the outputs of the devices. While some manufacturers of peripheral devices specifically manufacture the device to communicate with a given processor, it is more common to design an interface circuit that allows a peripheral device to communicate with a computer or another interface device. These interface devices provide the necessary logic and timing capability. Some peripheral devices have several interface circuits for each different function they perform. This problem with compatibility is not limited to computers and digital devices but is a common problem between any digital device that must communicate with another digital device. In addition, a need exists for a system which automatically aids in the design of state machines, decoders, and the like.
The above related invention provides an automatic approach to determine the necessary Boolean logic equations for the design of such interface circuits so that a peripheral device or system is fully compatible with the computer.
A need exists, therefore, to take the Boolean logic design equations, whether manually or automatically generated, and to partition the equations into a set of physical logic devices.
Currently there exists hundreds of logic devices of different types available to a designer for implementation in digital structures. These commercially available devices include programmable devices such as programmable logic devices (PLDs), programmable logic arrays (PLAs), programmable logic elements (PLEs), programmable logic sequencers (PLS), and programmable memories (PROMS); standard logic such as 7400 series TTL, 4000 series CMOS, and 10k series ECL; standard cells; and gate arrays. It becomes confusing and difficult for logic designers to process the shear magnitude (i.e., several thousand) of commercially available devices while still paying attention to such details as propagation delays, costs, family type, etc.
Significant engineering time can be consumed to manually partition Boolean logic design equations into commercially available devices. Furthermore, manual partitioning does not guarantee that the optimum design (i.e., the lowest cost, etc.) has been achieved.
A further need exists for an automatic system wherein the user of the system can specify physical constraints such as propagation delay, logic family, etc. and wherein the user can further specify partitioning directives such as signals appearing on specific pin assignments.
4. Solution to the Problem
The present invention provides a solution to the above problem by providing an automated partitioning system for designing, on a computer, the physical implementation of Boolean logic design equations into a set of physical logic devices that meets a user's constraints, partitioning directives and design goals.
The use of such constraints, partitioning directives, and design goals enables the user to significantly reduce the time spent in evaluating architectures and devices from different manufacturers.
Furthermore, the present invention, as opposed to prior manual layout approaches, automatically generates an optimal layout of inputs and outputs on one or more devices, again, thereby significantly reducing engineering time in the overall design effort.
The present invention further solves the above problem by ordering the possible partitioning solutions according to a cost value. The present invention provides output solutions in minutes compared to manual approaches that may take weeks of engineering effort.

Partitioning of Boolean logic equations into physical logic devices