A memory system comprising memory modules including memory chips stacked with switching circuits. A memory controller coupled to the memory modules is configured to initiate memory accesses. When a stacked switching circuit detects the memory access, the switching circuit routes the access to another memory module if the access is not directed to a memory chip of the receiving memory module, or processes the access locally if the access is directed to a memory chip of the receiving memory module. The memory controller and memory modules are coupled via bi-directional serial links. Each memory module may include multiple stacked switching circuits, each of which may be coupled to fewer than all of the memory chips within the memory module. Switching circuits further include circuitry configured to de-serialize data prior to conveyance to a memory chip, and serialize data received from a DRAM chip prior to transmitting the received data. Switching circuits may be coupled to a stacked memory chip via a flexible interconnect, and may also be manufactured side by side with a corresponding memory chip on a flexible circuit board.

1. Field of the Invention
This invention relates to memory subsystems and, more particularly, to the topology of a memory system architecture.
2. Description of the Related Art
Over the years, demands placed upon computing systems have increased. As demands increase and technology has advanced, efforts have been made to both increase the capacity of memory systems and reduce memory system latencies. In recent years, various proposals have been made, including proposals for fully-buffered dual-inline memory modules (FB-DIMMs). Traditionally, DIMMs have been configured to buffer both addresses and commands, but the data interface itself has been unbuffered. For a variety of reasons, including loading considerations, such designs have been unable to provide sufficiently high data rates when multiple DIMMs are placed on the same data channel. As a result, DIMMs that buffer data (i.e., FB-DIMMS), as well as addresses and commands, have been proposed. One such proposal includes a buffer chip on each DIMM and uses high-speed unidirectional point-to-point signaling between the memory controller and between DIMMs.
FIG. 1 (prior art) illustrates one embodiment of such a proposal which is being authored by the Joint Electron Device Engineering Council (JEDEC). Among other things, the proposal concerns FB-DIMMs which offer greater capacity including scalability of up to 192 GB and as many as six channels and eight DIMMs per channel. In the example shown, a system 100 is depicted which includes a processing unit 110, a host 120, and memory modules 130A, 130B, 130C, 130D, 130E, 130F. Each of the memory modules 130 are FB-DIMMs 130 and are configured on a channel 156 from the host 120 (e.g., a memory controller) which is in turn coupled to a processing unit 110. Elements referred to herein with a particular reference number followed by a letter will be collectively referred to by the reference number alone. For example, memory modules 130A-130F may be collectively referred to as memory modules 130. In addition, each of the FB-DIMMs 130A-130F includes an advanced memory buffer (AMB) 140A-140F, respectively. Each AMB 140 on the channel 156 must be uniquely identifiable to be addressable by the system.
A first FB-DIMM 130A is coupled to the host 120 by two separate links (160, 170). The first of these links 160 may be referred to as a "downstream" or "southbound" link, in which the first FB-DIMM 130A receives data and/or commands from host 120. The second of these links 170 may be referred to as an "upstream" or "northbound" link, by which data is conveyed from FB-DIMMs 130 to host 120. The remainder of the FB-DIMMs 130 in the embodiment shown are coupled to each other through a plurality of upstream and downstream links as illustrated. In general, a link may be referred to as an upstream link if information conveyed through the link is flowing towards the host 120, while a link may be referred to as a downstream link if information conveyed through the link is flowing away from host 120. The FB-DIMMs 130 are coupled to each other in what is commonly referred to as a "daisy-chain" arrangement.
Generally speaking, downstream communication takes place by sending fixed-size frames on the downstream links, with each frame being sent to each FB-DIMM 130 in turn. These downstream frames are generally pipelined one after another without any gaps. The content of all downstream frames is conveyed from the host 120. Upstream communication takes place by sending a pipelined sequence of fixed-size frames on the upstream links. The content of upstream frames may be updated by FB-DIMMs 130 as they are forwarded by them. All read and write commands, as well as write data, are sent on the downstream links. All read data is sent on the upstream links.
Scheduling of reads and writes is performed by host/memory controller 120. In order to simplify the scheduling, all read data is returned in the order in which it was requested. Thus, data read from a particular FB-DIMM 130 is placed in the first available upstream frame following the availability of the data, while data read from the first FB-DIMM 130A is delayed until the appropriate upstream frame passes it. Each FB-DIMM 130 knows the required latency from when it receives the downstream read command to when it inserts the corresponding read data into an upstream packet (these latencies must be deterministic; they are proposed to be configured during power-on of the channel, although there are questions about the deterministic nature of this initialization scheme). For example, if the propagation delay from one FB-DIMM to another is D ns and the latency for reading data on an FB-DIMM is R ns, and if there are no delays due to framing alignments, the Nth FB-DIMM from the host 120 would provide its read data R ns after receiving its command and the FB-DIMM nearest to the host would provide its read data R+2*(N−1)*D ns after receiving its command. Therefore, regardless of which FB-DIMM 130 is being read, the corresponding read data would arrive at the memory controller R+2*N*D ns after the command was sent out. Example values of N may typically vary from 1 to 8 or 16 and typical values of D may be in the range of 2 ns.
While the proposed scheme may provide for improvements over prior technologies, the limited number of DIMMs which may be utilized may be seen as undesirable. In addition, the nature of the above described latencies may also be undesirable.
In view of the above, an effective and efficient memory architecture is desired.

System memory board subsystem using DRAM with stacked dedicated high speed point to point links


This method includes the arrangement of a first sheet (22A) of porous material on a first face (18) of a base layer and of a second sheet (22B) of porous material of a second face (20) of the base layer before a heating step. Each sheet (22A, 22B) of porous material has a thickness of less than that of the formed layer (16).

A known part comprises a composite body including a layer of ceramic fibers, for example glass fibers, the ceramic fibers being embedded in a thermoplastic polymeric matrix such as polypropylene.
This type of material is designated by the commercial term of "Sommold".
In order to easily make this part, the usual method of the aforementioned type is known. In this method, a base mat comprising a mixture of ceramic fibers and polypropylene fibers is cut out beforehand to the form of the desired part.
Next, the mat is introduced between two heated plates which transmit the calories by conduction and by convection of the air trapped in the mat. This gives the possibility of rapidly and easily heating the base mat in order to cause melting of the polypropylene fibers. Next, the layer formed with the molten polymer is transferred into a cold mold which closes and compresses this layer down to the required thickness. The polypropylene flows through the glass fibers and forms, after cooling, the polymer matrix of the composite body which has the desired thickness, and the intended shape. The heating step before introduction into the mold simplifies the operation of the mold which does not have to be thermally regulated and reduces the cycle time, the preheating operation being performed in masked time during the molding operation per se.
The thereby produced composite body may be used as such, be assembled with a composite body of the same nature and form "double shell" parts or further be assembled on a honeycomb spacer in order to produce a composite part of the sandwich type. These parts receive in the majority of the cases, a cladding most often of the carpet type, either tufted or needled.
Generally, the mass proportion of glass fibers and of polypropylene fibers in the base mat is of the order of 50%.
The parts obtained by this method does not always give entire satisfaction. In certain applications, the requirements sheet for the part in particular implies resistance at a high temperature, being expressed by very low deflections under load, in particular at temperatures above 85° C. For example, this is the case for rear shelves of an automotive vehicle which are subject to temperatures of this order when the vehicle remains exposed to the sun for a long period of time.
Another drawback of Sommold parts lies in the fact that the technique for making the mat causes a certain number of glass fibers to be found oriented perpendicular to the plane of the mat. These poorly oriented glass fibers are again found even after molding within the finished part and may pierce the cladding thereby causing irritations for the operators and possibly for the final users.
In order to overcome this high temperature behavior problem of the composites based on ceramic fibers, the use, instead of polyolefin fibers, of a thermosetting polymer capable of crosslinking for generating three dimensional bridges between the macromolecular chains is known. Thermosetting polymers generally have high elastic moduli and a good high temperature behavior, with low creep. They are however difficult to recycle and the conformation of the thermosetting polymeric matrix may be complicated to apply industrially, essentially because of the duration of crosslinking which induces a high cycle time.
A thermosetting polymer family is very often associated with ceramic fibers and the family of unsaturated polyesters. Thus the term of GRP (glass-fiber reinforced plastic) in the majority of the cases makes reference to composites based on glass fibers reinforced with thermosetting unsaturated polyester resins. GRPs have been used for a long time as skins in sandwiched structures such as described in FR 2 580 991.
EP 0 628 406 proposes the use of different thermosetting resin types for producing skins of a structuring part of the sandwich type. Further, adhesion with the spacer is proposed so as to be achieved with resin which expands as a foam in order to partly penetrate into the spacer which allows reinforcement of the latter and ensures good adhesion with the skins.
Alternatively, EP-2 311 629 describes a structuring part of an automotive vehicle including a central spacer including a central spacer and two polymeric bodies attached on either side of the central spacer. Each body is obtained on the basis of two-component fibers in polyethylene terephthalate. In this case, the matrix as well as the reinforcement fibers are formed by a thermoplastic saturated polyester while the honeycomb spacer is also based on thermoplastic polyester. Because the spacer and the skins are of the same chemical nature, their adhesion may be strong which contributes to improving the flexural behavior. This product is easily recyclable since it is based on a single type of polymer.
Nevertheless, the method for applying these parts passes through a coating step which requires specific equipment and requires extrusion of two-component fibers which remains an expensive method. Moreover the elastic modulus of the terephthalate polyester fibers used as a reinforcement remains considerably less than that of the glass leading to composites of lesser performances.

Method of manufacturing a piece of automotive vehicle equipment and associated piece of equipment

Abstract: The sheets (22A, 22B) of porous material confine between them the molten polymeric material derived from the heat fusible polymer fibers during the heating step. The sheets (22A, 22B) of porous material are bound to the formed layer (16) after the step for building up the formed layer (16), in order to make up a first composite body (12A).


An apparatus and method for non-invasive treatment in lieu of cosmetic surgery is disclosed. The apparatus comprises a combination of a high and low voltage pulse generators connected to two or more electrodes placed on a treatment site of the patient's body. High voltage pulses, delivered to the electrodes, create an electric field that kills subcutaneous fat cells. Low voltage pulses, delivered to the same or individual electrodes provide transcutaneous electrical nerve stimulation (TENS), blocking the signals of discomfort or pain that may arise from the high voltage pulsing.

"Cosmetic surgery" is a phrase used to describe broadly surgical changes made to a human body with the usual, though not always, justification of enhancing appearance. This area of medical practice constitutes an ever-growing industry around the world. Obviously, where such a procedure fails to deliver an enhanced appearance, the procedure fails to meet the desired goal. One of the reasons that the majority of current procedures fail to deliver upon their promise is that, for the most part, current procedures are invasive, requiring incisions and suturing, and can have serious and unpleasant side effects, including but not limited to scarring, infection, and loss of sensation.
One of the more common forms of cosmetic surgery is the "face-lift." A face-lift is intended to enhance facial appearance by removing excess facial skin and tightening the remaining skin, thus removing wrinkles. A face-lift is traditionally performed by cutting and removing portions of the skin and underlying tissues on the face and neck. Two incisions are made around the ears and the skin on the face and neck is separated from the subcutaneous tissues. The skin is stretched, excess tissue and skin are removed by cutting with a scissors or scalpel, and the skin is pulled back and sutured around the ears. The tissue tightening occurs after healing of the incisions because less skin covers the same area of the face and neck and also because of the scars formed on the injured areas are contracting during the healing process.
Traditional face-lift procedures are not without potential drawbacks and side effects. One drawback of traditional cosmetic surgery is related to the use of scalpel and scissors. The use of these devices sometimes leads to significant bleeding, nerve damage, possible infection and/or lack of blood supply to some areas on the skin after operation. Discoloration of the skin, alopecia (boldness), is another possible side effect of the standard cosmetic surgery. The overall quality of the results of the surgery is also sometimes disappointing to the patients because of possible over-corrections, leading to undesired changes in the facial expression. Additionally, face-lift procedures require a long recovery period before swelling and bruising subside.
The use of lasers to improve the appearance of the skin has been also developed. Traditional laser resurfacing involves application of laser radiation to the external layer of the skin—the epidermis. Destruction of the epidermis leads to rejuvenation of the epidermis layer. The drawback of the laser resurfacing procedure is possible discoloration of the skin (red face) that can be permanent.
Another laser procedure involves using optical fibers for irradiation of the subcutaneous tissues, such as disclosed in U.S. Pat. No. Re36,903. This procedure is invasive and requires multiple surgical incisions for introduction of the optical fibers under the skin. The fibers deliver pulsed optical radiation that destroys the subcutaneous tissues as the tip of the fiber moves along predetermined lines on the face or neck. Debulking the subcutaneous fat and limited injury to the dermis along the multiple lines of the laser treatment results in contraction of the skin during the healing process, ultimately providing the face lift. The drawback of the method is its high price and possibility of infection.
Electrosurgical devices and methods utilizing high frequency electrical energy to treat a patient's skin, including resurfacing procedures and removal of pigmentation, scars, tattoos and hairs have been developed lately, such as disclosed in U.S. Pat. No. 6,264,652. The principle drawback of this technology is collateral damage to the surrounding and underlying tissues, which can lead to forming scars and skin discoloration.
Other forms of cosmetic surgery are also known. One example is liposuction, which is an invasive procedure that involves inserting a suction device under the skin and removing fat tissues. As with other invasive surgical procedures, there is always a risk of infection. In addition, because of the invasive nature of the procedure, physicians usually try to minimize the number of times the procedure must be performed and thus will remove as much fat tissue as possible during each procedure. Unfortunately, this procedure has resulted in patient deaths when too much tissue was removed. Assuming successful removal of excess fat tissue, further invasive surgery may be required to accomplish desired skin tightening.
The prior art to date, then, does not meet the desired goal of performing cosmetic surgery in a non-invasive manner while causing minimal or no scarring of the exterior surface of the skin and at the same time resulting in the skin tightening.
The term "electroporation" (EP) is used herein to refer to the use of a pulsed electric field to induce microscopic pores in the membranes of living cells. Living cells include a biological membrane, also commonly called a cell wall, that separates the inner volume of a cell, or cytosol, from the extracellular space, which is filled with lymph. This membrane performs several important functions, not the least of which is maintaining gradients of concentration of essential metabolic agents across the membrane. This task is performed by active protein transporters, built in the membrane and providing transport of the metabolites via controlled openings in the membrane. Inducing relatively large pores in the cell membrane by electroporation creates the opportunity for a fluid communication through the pores between the cytosol and the extracellular space that may lead to a drastic reduction of these vitally important gradients of concentrations of the metabolic agents. Uncontrolled exchange of metabolic agents, such as ions of sodium, potassium, and calcium between a living cell and the extracellular space imposes on the cell intensive biochemical stress.
When a cell is undergoing biochemical stresses the major biochemical parameters of the cell are out of equilibrium and the cell cannot perform its routine functions. In an attempt to repair itself, the cell starts worling in a damage control mode. The active protein transporters, or pumps, routinely providing transport of various metabolic agents, especially proteins, across membranes, use the energy of hydrogen or sodium positive ions passing from a positive potential of the intracellular space to a negative potential of the cytosol, or for the opposite direction the energy of a negative chlorine ion. This energy supply is provided by maintaining the potential difference across the membrane which, in turn, is linked to the difference in concentrations of sodium and potassium ions across the membrane. When this potential difference is too low, thousands of the active transporters find themselves out of power. Invasion of very high concentration of calcium ions from the interstitial space between cells, where the calcium ion concentration is about 100 times higher than in the cytosol, triggers an emergency production of actin filaments across the large pores in the membrane in an attempt of the cell to bridge the edges of the pores, pull the edges together, and thereby seal the membrane. In muscle cells the calcium ion invasion may cause lethal structural damage by forcing the cell to over-contract and rupture itself. Small pores in the membrane created by a relatively short electric pulse can reseal themselves spontaneously and almost instantaneously after the removal of electric field. No significant damage to the cell is done in this case. Contrary to that, larger pores may become meta-stable with very long life time and cause irreversible damage. It can be said that, depending on the number, effective diameter and life time of pores in the membrane, electroporation of the cell may result in significant metabolic or structural injury of the cell and/or its death. The cause of cell death after electroporation is believed to be an irreversible chemical imbalance and structural damage resulted from the fluid communication of the cytosol and the extracellular environment.
Below a certain limit of the electric field no pores are induced at all. This limit, usually referred to as the "lower EP limit" of electroporation, is different for different cells, depending, in part, on their sizes in an inverse relationship. That is, pores are induced in larger cells with smaller electric fields while smaller cells require larger electric fields. Above the lower EP limit the number of pores and their effective diameter increase with both the amplitude and duration of the electric field pulses.
Removing the electric field pulses enables the induced pores to reseal. This process of resealing of the pores and the ability of the cell to repair itself, discussed briefly above, currently is not well understood. The current understanding is that there is a significant range of electric field amplitudes and pulse durations in which cells survive electroporation and restore their viability thereafter. An electroporated cell may have open pores for as long as many minutes and still survive. The range of electric field amplitudes and pulse durations in which cells survive is successfully used in current biomedical practice for gene transfer and drug delivery inside living cells.
Nevertheless, the survivability of electroporated cells is limited. As the electric field amplitude and/or duration of pulses, increases, this limit, usually referred to as the "upper EP limit" of electroporation, is inevitably achieved. Above the upper EP limit, the number and sizes of pores in the cellular membrane become too large for a cell to survive. Multiple pulses cause approximately the same effect on the cells as one pulse with duration equal to the total duration of all applied pulses. After application of an electrical pulse above the upper electroporation limit the cell cannot repair itself by any spontaneous or biological process and dies. The upper EP limit is defined by the combinations of the amplitudes of electric field and pulse durations that cause cellular death.
The vulnerability of cells to electroporation depends on their size: the larger the cell, the lower the electric field and duration of a pulse capable of killing it. If cells of different sizes are exposed to the same electric field, the largest cells will die first. Thus, this ability of electroporation to discriminate cells by their sizes may be used to selectively kill large cells in the human body.
In the previously referred to application for United States patent application entitled "Apparatus and Method for Reducing Subcutaneous Fat Deposits, Virtual Face Lift and Body Sculpting by Electroporation", Ser. No. 09/931,672, filed Aug. 17, 2001, an apparatus and method for performing non-invasive treatment of the human face and body by electroporation in lieu of cosmetic surgery is disclosed. The apparatus comprises a high voltage pulse generator and an applicator having two or more electrodes utilized in close mechanical and electrical proximity with the patient's skin to apply electrical pulses thereto. The applicator may include at least two electrodes with one electrode having a sharp tip and another having a flat surface. High voltage pulses delivered to the electrodes create at the tip of the sharp electrode an electric field high enough to cause death of relatively large subcutaneous fat cells by electroporation. Moving the electrode tip along the skin creates a line of dead subcutaneous fat cells, which later are metabolized by the body. Multiple applications of the electrode along predetermined lines on the face or neck create shrinkage of the skin and the subcutaneous fat reduction under the treated area.
The electroporation in-vivo, employed in the disclosed method of treatment of subcutaneous fat, involves high voltage pulses applied to the skin of a patient. Delivery of such pulses, however, may result in the patient experiencing an unpleasant sensation of small, but palpable electric jolt or shock during pulsing.
The electric current passing the skin and surrounding tissues between electrodes excites sensory nerves and may cause a discomfort sensation or even pain. This perception is the end result of a process that begins with stimulation of a peripheral sensory nerve and culminating in the conscious awareness of the pain at the cerebral cortex. There are several levels of organization within the central nervous system at which the perception of pain may be interrupted, thereby providing the opportunity to prevent the sensation of pain by a patient.
The perception of pain begins with stimulation of a distal peripheral sensory nerve. The stimulation signal travels to a higher level of sensory collection, which is at the dorsal sensory nerve root ganglion just laterally of the spinal cord. The signal enters the spinal cord and ascends to the brain stem, from which it traverses onto the sensory strip along the cerebral cortex. Each area of the cortex in this strip represents a surface area of the body in a fashion known as the homunculus distribution of the cerebral cortex.
Various procedures and drugs have been employed in the past to interrupt the perception of pain at these various levels. Peripheral nerve blockade is achieved through various methods, the most common of which is a local nerve block with medications such as lidocaine injected at the procedure site.
A variety of medications can be used in local, regional and general anesthesia. Drugs are available for local tissue injection providing a direct anesthetic block at the sensory nerve ends. Other drugs are used for intravenous delivery and disseminate throughout the entire body and produce a general anesthesia effect. Intermediate to this, medications have been developed for direct injection into nerve bundles to provide a regional type of anesthetic block. Such examples of regional anesthesia are axillary nerve blocks putting the arm to sleep, sacral nerve blocks putting the back of the leg to sleep, and saddle blocks or epidural blocks that render the entire lower half of the body anesthetized.
Anesthetic drugs are efficient in reducing or blocking the sensation of pain, but they have their own drawbacks. They can have toxic side effects or cause allergic reactions in certain patients. Also, they can significantly increase the cost of surgical or other procedures. Whenever it is possible, it is desirable to avoid usage of the pharmacological drugs for pain control.
The Gate Control Theory of pain was initially proposed in 1965 by Melzack and Wall and now is widely accepted by the scientific community. The Gate Control Theory provides that large and small diameter nerve fibers, both of which carry pain signals, travel through the same "gate mechanism." The theory further provides that activated large nerve fibers can inhibit the transmission of a pain signal by the smaller nerves fibers.
Chemicals released as a response to the pain stimuli also influence whether the gate is open or closed for the brain to receive the pain signal. This lead to the theory that the pain signals can be interfered with by stimulating the periphery of the pain site, the appropriate signal-carrying nerves at the spinal cod, or particular corresponding areas in the brain stem or cerebral cortex. It is generally recognized that the "Pain Gate" can be shut by stimulating nerves responsible for carrying the touch signal (mechanoreceptors). This finding enables the relief of pain through massage techniques, rubbing, and also the application of hot wheat bags or cold ice packs. The Gate can also be shut by stimulating the release of endogenous opioid-type chemicals that are released by the body in response to the pain stimuli.
One of non-drug mediated pain control techniques is called Transcutaneous Electrical Nerve Stimulation (TENS). It is based on a discovery that application of electrical current to the body can also interfere with transmission of pain signals along the nerve pathways and give patients a significant analgesic (pain relieving) effect. The Gate Control Theory of pain suggests that this effect is mediated by endogenous pain relieving chemicals, released by the body in response to the electric transcutaneous stimulation, consequently blocking the ability of the nerve to transmit pain signals. If a large nerve, responsible for transmission of perception of heat or touch, is carrying periodic signals from the endings on the skins, the Gate for the pain signals transmitted to the spinal cord via small nerves are closed and the pain is reduced.
Currently TENS is used primarily for symptomatic relief and management of chronic intractable pain or as an adjunctive treatment in the management of post-surgical or post-traumatic acute pain. TENS usually involves the application of a sequence of short electrical pulses with relatively low repetition rate intended to affect the nervous system in such a way as to suppress the sensation of pain from acute or chronic injury. Typically, two electrodes are secured to the skin at appropriately selected locations. Mild electrical impulses are then passed into the skin through the electrodes to interact with the underlying nerves over the treatment site. As a symptomatic treatment, TENS has proven effective in the reduction of both chronic and acute pain of patients.
It would be desirable to have a method and apparatus that could mitigate the discomfort created by the electroporation in-vivo without resorting to anesthetic drugs using non-pharmocological aids.

This patent is subject to a terminal disclaimer.

Apparatus and method for reducing subcutaneous fat deposits by electroporation with improved comfort of patients


A portable programmable sign comprising a unitary T-shaped housing having opposed front and rear sides and including an upper sign portion and a lower hand-held portion mounted midway transverse to the sign portion. A keyboard system with a miniaturized keyboard processor including keys marked with indicia for letters of the alphabet, numerals, and other selected indicia is mounted on the hand grip for operator input. Operating keys are also mounted on the keyboard. The sign includes a miniaturized computer microprocessor for processing input data received from the keyboard. A miniaturized light-emitting message display, preferably an LED display, is mounted on the front side of the sign portion for reading by an observer. An electrical circuit in the housing joins the keyboard system, computer microprocessor, and the light-emitting message display are joined by an electrical circuit in the housing and which can be internally or externally powered. An optional miniaturized monitor display system mounted on the rear side of the sign portion receives the input data from the computer microprocessor prior to transmission of the input data so that a user can edit or verify the accuracy of the input data prior to transmission of the data to the light-emitting message display.

Messages are called for in many situations where speech cannot be used or can be used only with difficulty. A few examples are as follows: areas where noise levels are very high; areas where silence is preferred or in zero noise areas, such as in the military, during test taking or during church services; construction areas such as high buildings or in sewers where the voice cannot be heard clearly; boat to boat communications; and between swimmers or between a swimmer and a boat in underwater activity.
Computers have not been associated with portable, or hand-held, sign technology partly because monitor viewing screens are dominated by the fluorescent screen associated with the cathode ray tube (CRT) technology, which has until recently been bulky. Miniaturized microprocessor technology has recently allowed reduction of CRT monitors with displays that are as crisp and readable as laser printing on paper.
Computer display technology is presently used with displays that are based upon the well-known liquid crystal display (LCD), such as are used for messages displayed on the screens of bank cash vending machines. LCDs could be used in operative association with miniaturized microprocessor technology.
The same miniaturized technology has reduced motherboard processors so that an entire package including display and microprocessor is reduced to fit into a shirt pocket, that is to say, to the rectangular dimensions of a credit card. Such advances in miniaturized microprocessor technology can be applied as well to keyboard processors.


The invention relates to a thermal control system for controlling the temperature of a fluid. In particular, the invention relates to a control system having at least two heating elements, at least one of which is used for directly or indirectly heating a fluid, and at least one of which is used for heating a thermal probe used to determine the temperature of the fluid. The heating systems are controlled by at least one feedback controller.

Thermal control systems for controlling the temperature of a fluid have uses in a variety of contexts, such as when conducting measurements on the fluid that may have temperature dependence. For example, a multitude of laboratory tests for analytes of interest are performed on biological samples for diagnosis, screening, disease staging, forensic analysis, pregnancy testing, drug testing, and other reasons. While the majority of quantitative tests still require the expertise of trained technicians in a laboratory setting using sophisticated instruments, portable sensing systems have been and are continuing to be developed. Many such sensing systems have a need for maintaining small amounts of a fluid, such as blood, at a constant predetermined temperature.
A disposable sensing device for measuring analytes in a sample of blood is disclosed by Lauks in U.S. Pat. No. 5,096,669. Other devices are disclosed by Davis et al. in U.S. Pat. Nos. 5,628,961 and 5,447,440 for a clotting time. These devices employ a reading apparatus and a cartridge that fits into the reading apparatus for the purpose of measuring analyte concentrations and viscosity changes in a sample of blood as a function of time. A potential problem with such disposable devices is variability of fluid test parameters from cartridge to cartridge due to manufacturing tolerances or measurement condition variability. Zelin, U.S. Pat. No. 5,821,399 discloses methods to overcome this problem using automatic flow compensation controlled by a reading apparatus using conductimetric sensors located within a cartridge. U.S. Pat. Nos. 5,096,669, 5,628,961, 5,447,440, and U.S. Pat. No. 5,821,399 are hereby incorporated in their respective entireties by reference.
Antibodies are extensively used in the analysis of biological analytes. For a review of basic principles see Eddowes, Biosensors 3:1-15, 1987. U.S. Pat. No. 5,807,752 to Brizgys discloses a test system in which a solid phase is impregnated with a receptor for an analyte of interest. A second analyte-binding partner attached to a spectroscopically-determinable label and a blocking agent is introduced, and the spatial distribution of the label is measured. Spectroscopic measurements require a light transducer, typically a photomultiplier, phototransistor, or photodiode, and associated optics that may be bulky or expensive, and are not required in electrochemical methods, in which an electrical signal is produced directly.
Electrochemical detection, in which binding of an analyte directly or indirectly causes a change in the activity of an electroactive species adjacent to an electrode, has also been applied to immunoassay. For a review of electrochemical immunoassay, see: Laurell et al., Methods in Enzymology, vol. 73, "Electroimmunoassay", Academic Press, New York, 339, 340, 346-348 (1981).
U.S. Pat. No. 4,997,526 discloses a method for detecting an analyte that is electroactive. An electrode poised at an appropriate electrochemical potential is coated with an antibody to the analyte. When the electroactive analyte binds to the antibody, a current flows at the electrode. This approach is restricted in the analytes that can be detected; only those analytes that have electrochemical midpoint potentials within a range that does not cause the electrode to perform non-specific oxidation or reduction of other species present in the sample by the electrode. The range of analytes that may be determined is extended by the method disclosed in U.S. Pat. No. 4,830,959, which is based upon enzymatic conversion of a non-mediator to a mediator. Application of the aforementioned invention to sandwich immunoassays, where a second antibody is labeled with an enzyme capable of producing mediator from a suitable substrate, means that the method can be used to determine electroinactive analytes.
Microfabrication techniques (e.g., photolithography and plasma deposition) are attractive for construction of multilayered sensor structures in confined spaces. Methods for microfabrication of electrochemical immunosensors, for example on silicon substrates, are disclosed in U.S. Pat. No. 5,200,051 to Cozzette et al., which is hereby incorporated in its entirety by reference. These include dispensing methods, methods for attaching biological reagent, e.g., antibodies, to surfaces including photoformed layers and microparticle latexes, and methods for performing electrochemical assays.
In an electrochemical immunosensor, the binding of an analyte to its cognate antibody produces a change in the activity of an electroactive species at an electrode that is poised at a suitable electrochemical potential to cause oxidation or reduction of the electroactive species. There are many arrangements for meeting these conditions. For example, electroactive species may be attached directly to an analyte (see above), or the antibody may be covalently attached to an enzyme that either produces an electroactive species from an electroinactive substrate, or destroys an electroactive substrate. See, e.g., M. J. Green (1987) Philos. Trans. R. Soc. Lond. B. Biol. Sci. 316:135-142, for a review of electrochemical immunosensors.
The concept of differential amperometric measurement is well known in the electrochemical art. See, for example, jointly owned Cozzette, U.S. Pat. No. 5,112,455. In addition, a version of a differential amperometric sensor combination is disclosed in jointly owned Cozzette, U.S. Pat. No. 5,063,081.
The art contains references to immunosensors for detection of human serum albumin using an antibody to human serum albumin for capture. These include Paek, (U.S. Pat. No. 6,478,938), Berggren (U.S. Pat. No. 6,436,699), Giaever (U.S. Pat. No. 3,853,467), Yamazoe (JP 07260782) and Owaku (JP 05273212).
Miller, U.S. Pat. No. 7,723,099 discusses an immunoassay device with an immuno-reference electrode. The electrochemical measurements made on such samples are temperature dependent. Thus, precise temperature control over the fluid being analyzed is essential for accurate results. Such temperature control can be made difficult by the existence of an offset between the temperature measuring device and the fluid due to an unknown thermal resistance between the two. Further, such devices rely on a relatively small amount of blood or fluid sample. As a result of its small volume and thermal mass, the fluid temperature can be affected by the temperature and heat capacity of the temperature measuring probe itself. Therefore, the need exists for a thermal control system to control the temperature, in particular when the fluid is present in low volume and/or has a relatively low thermal mass.

Thermal control system for controlling the temperature of a fluid


This disclosure relates to misalignment-tolerant processes for fabricating multiplexing/demultiplexing architectures. One process enables fabricating a multiplexing/demultiplexing architecture at a tolerance greater than a pitch of conductive structures with which the architecture is capable of communicating. Another process can enable creation of address elements and conductive structures having substantially identical widths.

Electrical communication in and out of an array of thin wires, especially arrays having wires thinner than 1000 nanometers, can be difficult. One reason for this difficulty is that thin wires in arrays are often spaced closely together. This close spacing can make connecting an electrical bond pad with each wire impractical.
One structure for electrically connecting to wires of an array is called a multiplexing/demultiplexing architecture (a "mux/demux architecture"). The mux/demux architecture does not need an electrical bond pad to be connected or aligned with each wire of an array. Instead, one bond pad is typically connected to all of the wires of the array.
This one bond pad does not, however, allow communication with each wire of the array individually. To differentiate between wires, address elements, such as transistors, can be contacted with each of the wires. For a 16-wire array, for instance, four transistors can be contacted with each wire. By selectively turning the transistors on and off, only one of the 16 wires can be permitted to communicate with the one bond pad. Manufacturing this mux/demux architecture is typically less expensive and more reliable than connecting a bond pad to each wire.
In FIG. 1, for instance, an array of wires 102 with wires and spacing well above 1000 nanometers, is electrically connected to one bond pad 104. Wires 106 of the array 102 can be communicated with separately using a binary mux/demux architecture shown at numeral 108. This mux/demux 108 has four different address circuits 110, 112, 114, and 116, each of which communicates with a set of transistors 118 through two address lines. The signals sent to each set of two address lines are complimentary. These address circuits can turn on or off the transistors 118 to which they are connected. By turning the transistors 118 on and off, only one of the wires 106 can be permitted to pass a measurable current from a power supply 120 to the bond pad 104.
For example, a measurable current can travel from the power supply 120 through a third wire 122 (counting from top) to the bond pad 104 only if all four of the transistors 118 that are in contact with the third wire 122 are turned on. The transistors 118 of the third wire 122 are turned on by turning the address circuit 110 on, the circuit 112 on, the circuit 114 off, and the circuit 116 on. When on, the transistors 118 on the "Logical YES" side of each of the address circuits turn on and on the "Logical NOT" side turn off, and vice-versa. Address wires 124, 126, 128, and 130 are used to turn the address circuits 110, 112, 114, and 116 on or off, respectively.
Using this type of mux/demux architecture, a number of address elements (here transistors 118) are used for each wire. This number of elements can increase with higher numbers of wires in an array. For the array 102, which has only 16 wires, four transistors 118 are used for each of the wires 106. For an array having 32 wires, this architecture uses five address elements. For 64 wires, it uses six address elements, for 128 seven, for 256 eight, for 512 nine, and so forth.
Another type of mux/demux includes h-hot architectures. H-hot architectures control wires of an array with a set number (h) of address elements and address wires controlling each wire. For example, if an h-hot mux/demux architecture has m address wires and h address elements on each wire (e.g., transistors), the maximum array size is the combination of h out of m: (Cmh).
The mux/demux architecture 108 (and typical h-hot architectures) use address elements (like transistors, diodes, and resistors) built using multiple patterned layers and circuit elements (like address lines and wires). Aligning these elements (or layers) with the wires 106 can be accomplished with typical processing machines if the wires 106 of the array 102 are large enough and spaced far enough apart. For narrow wires and spaces, however, the mux/demux architecture 108 may not be able to align the address elements with sufficient accuracy to meet a tolerance of the narrow wires and spaces.
There is, therefore, a need for a system and method capable of communicating with arrays having small wires and spaces that is reliable, less expensive, and/or more production-friendly than permitted by present-day techniques.
The same numbers are used throughout the disclosure and figures to reference like components and features.

Misalignment-tolerant methods for fabricating multiplexing/demultiplexing architectures

Hewlett-Packard Development Company, L.P.


A single queuing structure enqueues requests of multiple priorities. The queuing structure is especially well adapted for use with requests that are part of AGP operations. For instance, the queuing structure may enqueue low priority read requests, high priority read requests, low priority write requests, and high priority write requests. The queuing structure may be logically partitioned into logical sub-queues where each sub-queues is associated with requests of a given type and a given priority. Each of the logical sub-queues may be configured to operate in a first-in-first-out (FIFO) fashion. Separate pointers may be maintained for identifying the bottom of each of the logical sub-queues within the single queuing structure.

The peripheral component interconnect (PCI) specification has been widely adopted in conventional computer systems. The PCI specification defines a local bus system, that includes a PCI bus and a PCI controller for regulating access to the bus. The PCI bus may be connected to different peripheral devices via expansion cards and data may be exchanged between the peripheral devices and a central processing unit (CPU) over the PCI bus. The peripheral devices may seek access to memory locations in main memory over the PCI bus by sending requests to a system memory controller. Each such request to access the system memory is sent as part of a memory access transaction in a non-pipelined fashion. In particular, for each memory access transaction, a memory request is sent from a sender over the PCI bus to the system memory controller, and the sender waits on the request until a response is received. This approach has proven to be especially cumbersome for memory intensive applications, such as three-dimensional rendering, that require a great deal of bandwidth. Unfortunately, the PCI bus does not readily facilitate such a great deal of bandwidth. As a result, the PCI bus serves as a substantial bottleneck for quickly rendering three-dimensional images.
In response to the limitations of the PCI specification, Intel Corporation has established the Accelerated Graphics Port (AGP) specification. AGP is a high performance component level interconnect that is designed for use with three-dimensional graphic display applications. The AGP specification identifies an AGP bus and interface requirements for AGP compliant devices. AGP is based upon a set of performance extensions of the PCI specification that provide increased bandwidth to help better facilitate the large memory bandwidth requirements that are necessary for three-dimensional rendering. AGP provides three primary areas of extensions relative to PCI. First, memory read and write operations are pipelined to hide memory access latency. Second, address data is demultiplexed on the bus to enhance bus efficiency and third, AC timing is provided for 133 MHz data transfer rates.

Multiple priority accelerated graphics port (AGP) request queue


In an outer rotor motor (1): a hub base (3) is in a center of an upper side of the motor (1); a chucking magnet (16) for carrying a disk is near the hub base (3); a spindle (4) is fixed to a central hole of a rotor yoke which is provided with a permanent magnet (15) in its outer peripheral portion; the spindle (4) is supported by a bearing (5) fixed to a boss (7b) of a bearing housing (7) in which a ring-like rib (7c) is concentrically formed around the boss (7b) to form a circumferential groove (7d) therebetween and a hub of a stator (8) is mounted on the rib (7c); a leaf spring (12) is over the groove (7d) of the bearing housing placed under the base (3); and a drive pin (10) is fixed to a free end of the spring (12) to extend upward from the base (3) due to its resiliency through a hole of the hub base (3).

1. Field of the Invention
The present invention relates to a brushless DC outer rotor motor which is used as a spindle motor for driving a magnetic disk of a thin and small magnetic recording unit.
2. Description of the Prior Art
In a motor 21 which is shown in FIGS. 4 to 7 and rotatably drives a recording medium or disk such as magnetic disks, optical disks and like disks in a recording unit, there is provided a drive pin 10 on its hub base 3 adapted to be loaded with the disk.
The drive pin 10 engages with a reference hole formed in a hub portion of the disk, and is adapted to drive the disk upon energizing of the motor. As shown in FIG. 5, the drive pin 10 is mounted on a free end of a leaf spring 12 which has its base portion fixedly mounted on an lower surface of the hub base 3 by means of screws and like fasteners, thus allowing the leaf spring 12 to urge the drive pin 10 to extend above the upper surface of the hub base 3 or disk-loading surface side through a through-hole 13 formed in the hub base 3.
When the disk is set in a reference position of the hub base 3, the drive pin 10 enters the reference hole of the disk to engage with the disk. However, when the disk is set in any other position of the hub base 3 except the reference position thereof, the drive pin 10 receives the weight of the disk and is depressed thereby so that the leaf spring 12 is resiliently pushed towards the lower side of the hub base 3 against its resiliency, as shown in FIG. 4 by a dotted line.
In operation, since the hub base 3 is rotatably driven when the motor is energized, it is necessary to provide a space for permitting the leaf spring 12 to pass therethrough when the disk is set in any other position except the reference position, the space being provided under the lower side of the hub base 3. Due to the above reason, the hub base 3 is not directly provided in the rotor yoke 2 of the motor, but fixedly mounted on an end portion of a rotary shaft or spindle 4, the end portion being on the opposite side from the rotor yoke 2.
The reason why the hub base 3 is not mounted on the rotor yoke 2 is that although the housing 22 for the bearings 5 for the supporting the spindle 4 of the motor is press-fitted to an inner one 9a of inner and outer double hubs 9a, 9b formed in the central portion of a stator 8, it is not possible to provide an ample space between the front ends of vertical needle terminals 17 and the inner surface of the rotor yoke 2, and therefore the free end of the leaf spring 12 is prevented from easily passing therebetween when the disk is set in any other position except the reference position. Because in the space between the inner and outer double hubs 9a, 9b, there are provided various parts such as the vertical needle terminals 17 connected with wires leading to coils 14 of the stator's pole plates, as shown in FIGS. 6 and 7, such ample space can not be provided therebetween.
When the space between the front ends of the vertical needle terminals 17 and the inner surface of the rotor yoke 2 is increased, it is possible for the thus resiliently bent leaf spring 12 to pass therebetween. However, this poses the problem of requiring the motor to have a large height, which makes it impossible to use a motor with a thin thickness.
Further, in the motor of the recording unit, there are provided an indexing magnet in the rotor yoke 2 of the motor for detecting a reference starting position in recording of the disk and a magnetic detection device (which is constructed of a Hall device for detecting the indexing magnet) on a printed board.
In a conventional motor 21, as shown in FIGS. 14 and 15 the indexing magnet 19 is mounted on an outer peripheral surface of the rotor yoke 2 of the motor 21 and the magnetic detection device 20 is fixedly mounted on the printed board 18 so as to be disposed outside the rotor yoke 2.
As described above, in the conventional motor 21, since the indexing magnet 19 is mounted on the outer peripheral surface of the rotor yoke 2 of the motor 21, it is necessary to precisely determine positions of both the indexing magnet and the drive pin provided in the hub base in assembling. When these positions are not determined properly in assembling, magnetic recording properties of the recording unit becomes unstable, which is a problem inherent in the conventional motor.
In addition, since the indexing magnet extends horizontally outward from the outer periphery of the rotor yoke and the magnetic detection device for detecting it is provided on the printed board in the position outside the rotor yoke, it is actually impossible to provide other components on the printed board near the rotor yoke. Consequently, hitherto the printed board is not effectively used in its component-packaging space, and, therefore it is not possible for the motor to cope with the need that the motor should be smaller in size.

Minebea Kabushiki-Kaisha (Minebea Co., Ltd)


The present invention relates to an electrorheological fluid composition comprising a dispersion of a plurality of solid particles in an electrically non-conducting liquid, the improvement comprising using as said solid particles a composition having the general formula: EQU [(M).sup.p (H.sub.2 O).sub.x (OH).sub.y ].sup.q.sub.c [A].sup.r.sub.d.B.sub.z.nH.sub.2 O. wherein M is a metal cation or a mixture of metal cations at various ratios; p is the total valence of M and has a value of greater than zero; x is zero or has a value greater than zero, y is zero or has a value greater than zero, with the proviso that only one of x or y can be zero at any given time; q has a value of p minus y with the proviso that q has a value of at least one; c has a value of greater than zero; A is an anion or a mixture of anions at various ratios; r is the total valence of A with the proviso that r has a value of at least one; d has a value of greater than zero with the proviso that (q.times.c) is always equal to (r.times.d); B is an amino acid or a mixture of amino acids; z has a value of from 0.01 to 100; and n is a number from 0 to 15. The ER fluids of the present invention have greatly improved yield stress increasing potential stress transfer characteristics, and good dispersion stability.

The present invention relates to an electrorheological fluid comprising a dispersed phase and a base liquid wherein the dispersion consists of finely divided particles of a metal amino acid salt.
Electrorheological (ER) fluids are composed of a polarizable solid phase dispersed in a dielectric fluid phase. ER fluids are unique in that they have the ability to change their characteristics from liquid-like to solid-like upon application of an external voltage. This change is reversible which means that the liquid-like state returns upon removal of the electric field. Upon application of a voltage, the solid particles form fibril-like networks which bridge the electrode gap. At this point, the material will not behave as a Newtonian fluid, but will exhibit a Bingham plastic behavior. Fluids exhibiting the Bingham plastic effect require application of a particular level of force (yield stress) before the material will flow again.
It is desirable in the ER fluid art to improve the strength of such fluids which thereby permits smaller devices requiring less power drive to be built. The production of an ER fluid with greater strength would also allow devices to be operated at lower voltages, which would have advantages in power supply design, and generally would open up other application areas for the use of ER fluids that are currently beyond the capabilities of existing ER fluids. It is also desirable in an electrorheological fluid to match the density of the solid phase with the density of the fluid phase.
Aluminum based particle systems have been described in the art. For example, Goosens et al., in U.S. Pat. No. 4,702,855, discloses ER fluids based on aluminum silicates in an electrically non-conducting liquid and a suitable dispersing agent. The contribution to the art provided by this patent was an improved electroreactivity, as well as improved stability over a wide temperature range. This was accomplished by the addition of certain polysiloxane dispersants to the ER fluid formulations.
There also have been several ER particle systems which have described that either colloidal aluminum or colloidal zirconia or a mixture thereof could be utilized in the disperse phase of an ER fluid. For example, Hashimoto et al., Japanese Patent Application Laid Open 01304188, discloses an electroviscous fluid which consists of 5 to 50 weight percent of a dispersion of particles of 5 to 1000 microns in diameter and 95 to 50 weight percent of a liquid phase of a nonreactive or modified silicone oil having a 0.90 to 1.30 specific gravity. The particles can be one or a mixture of more than one of colloidal silica, colloidal alumina, colloidal zirconia, or antimony oxide.
Japanese Patent Application Laid Open No. 01172496 teaches an electroviscous fluid obtained by dispersing dielectric particles into an oily medium high in electrical insulation, the dielectric particles comprise hollow bodies into which the oily medium will not permeate. Examples of the dielectric particles are the metallic oxides of silica, alumina, silica-alumina, spinel, zirconia, and titanium oxide or vanadium oxide; metals such as aluminum, silicon, nickel or copper; ferroelectric substances such as calcium titanate or strontium titanate; or of a synthetic high polymer such as polyvinylidene fluoride, polyamide or an ion exchange resin. The fluid is disclosed as having long-term stability.
Japanese Patent Application Laid Open No. 03166295 teaches an electroviscous fluid having improved dispersibility comprising dielectric particles dispersed in an electrically insulating liquid which has main particles having a grain size of 3-100 microns and contains finer particles having an average grain size of 0.3 micron to 20% of the average grain size of the main particles. Available materials for the finer particles include polyamides, MgO, Zr oxide, silica, alumina, Ti oxide, and Si nitride. Available materials for main dielectric particles include starch, cellulose, casein, ion exchange resins, silica, alumina, silica-alumina, Al.sub.2,(OH).sub.3, Zn(OH).sub.2, mica, and lithium and potassium tartrate.
Japanese Patent Application Laid Open No. 03200897 discloses a new fluid composition which consists of one or a mixture of inorganic ion-exchanged materials comprising hydroxides of polyvalent metals, acidic salts of polyvalent metals, and potassium titanates dispersed in an electrically insulating dipersion medium. Preferred polyvalent metal hydroxides include titanium, zirconium, and magnesium hydroxide. Acidic salts of polyvalent metals include zirconium phosphate and titanium arsenate.
Other particle systems which have been described in the ER fluid art recently are silicone amine sulfate particles dispersed in polydimethylsiloxane fluid as described in U.S. Pat. No. 4,994,198, and lithium-polymethylmethacrylate particles dispersed in a chlorinated paraffin base fluid as described in Great Britain Unexamined Application No. 1570234.
However none of the references described hereinabove teach a hydrolyzable metal amino acid salt which produces an electrorheological fluid having unexpectedly high yield stress values while retaining good dispersion stability in compatible base liquids.

Electrorheological (ER) fluid based on amino acid containing metal polyoxo-salts


Exemplary embodiments described in this disclosure are generally directed to systems and methods for displaying visual content in an automobile. In an exemplary implementation, an onboard computer of an automobile receives wireless signals from a roadside unit located near the traffic intersection. The wireless signals provide information about how much time is remaining before a traffic light turns from a red state to a green state. The onboard computer uses this information to display visual content on an infotainment system in the automobile as long as the automobile is in a stopped condition. The onboard computer stops displaying the content before the traffic light turns green. In one case, the wireless signals transmitted from the roadside unit include a Signal Phase and Timing (SPaT) signal and a traffic intersection map that provides details about a topography of the traffic intersection.

Most automobiles now include various types of devices that are intended to enhance driving safety and/or to offer more functionalities. For example, a wireless communication device such as a Bluetooth® telephone system allows a driver to keep his/her hands on the steering wheel and eyes on the road. As another example, an infotainment system may be used not only for listening to music (as was done in the past by using a radio), but for additional purposes such as for obtaining navigation instructions, to look up a phone number in a phone directory, or to watch some types of video content. Certain actions performed by a driver of the automobile may include a need to look at a display screen of the infotainment system and/or to touch an icon on a touch screen of the infotainment system.

Systems and methods for displaying visual content in an automobile stopped at a traffic light


According to this invention, a noise shaper circuit capable of realizing an integrated circuit having a small chip area is provided.. In calculating circuits for calculating input data represented by a twos complement and feedback data of output data converted into data having a small word length, the input data is divided into upper bits and lower bits with respect to a bit rounded off during a word length converting operation, only the upper bits are used in a calculation, and the calculation result and the lower bits which are not used in the calculation are added to the LSB of the calculation result again, and the resultant data is output to the next stage.

The present invention relates to a noise shaper circuit used in a digital/analog converter of an over-sampling method and, more particularly, to a noise shaper circuit, using a .DELTA. modulation method or a .DELTA..SIGMA. modulation method, for rounding data having an arbitrary number of bits into data having a smaller number of bits.
As a conventional noise shaper circuit used in a digital/analog converter of an over-sampling method, a circuit having characteristics represented by a signal flow graph of a secondary .DELTA..SIGMA. modulator shown in FIG. 2 is generally used. However, when this flow graph is directly realized as a circuit, four calculating circuits 11 to 14 each having a large word length are required, i.e., the circuits 11 to 14 requires a large chip area when the circuits are integrated.
Therefore, as shown in FIG. 3, a circuit in which the number of calculating circuits is decreased to reduce a chip area and a signal flow graph is modified is proposed ("IEEE JOURNAL OF SOLID-STATE CIRCUITS" VOL. SC-22, NO. 3, PP. 390-394, June, 1987). The transfer characteristics of this circuit are the same as those of the circuit in FIG. 2. This circuit of FIG. 3 has three calculating circuits 21, 22, and 23, and the number of calculating circuits is smaller than that of the circuit in FIG. 2. However, when the signal flow graph in FIG. 3 is to be realized in an integrated circuit, the following problem is posed. That is, in processing of data having a large word length, since the wiring lines of the circuit in FIG. 3 are more complicated than those of the circuit in FIG. 2, the data having a large word length requires a large area for data lines. Therefore, the chip area of the integrated circuit is not so reduced.
In FIGS. 2 and 3, reference numerals 15, 16, 18, 24, and 25 denote delay circuits; 17, 28, and 29, quantizers; and 26 and 27, amplitude limiters.
As described above, when a conventional noise shaper circuit is to be realized in an integrated circuit, a chip area is disadvantageously large.


A multiple matchline sense circuit for detecting a single, more than one, or no match conditions during a search-and-compare operation of a content addressable memory is disclosed. The circuit compares the rising voltage rate of a multiple matchline to the rising voltage rate of a reference multiple matchline in order to generate a multibit result representing one of the three conditions. The circuit generates a self-timed control signal to end the search-and-compare operation, and to set the circuit to a precharge state.

In many conventional memory systems, such as random access memory, binary digits (bits) are stored in memory cells, and are accessed by a processor that specifies a linear address that is associated with the given cell. This system provides rapid access to any portion of the memory system within certain limitations. To facilitate processor control, each operation that accesses memory must declare, as a part of the instruction, the address of the memory cell/cells required. Standard memory systems are not well designed for a content based search. Content based searches in standard memory require a software based algorithmic search under the control of the microprocessor. Many memory operations are required to perform a search. These searches are neither quick nor efficient in using processor resources.
To overcome these inadequacies an associative memory system called Content Addressable Memory (CAM) has been developed. CAM allows cells to be referenced by their contents, so it has first found use in lookup table implementations such as cache memory subsystems and is now rapidly finding use in networking systems. CAM's most valuable feature is its ability to perform a search and compare of multiple locations as a single operation, in which search data is compared with data stored within the CAM. Typically search data is loaded onto search lines and compared with stored words in the CAM. During a search-and-compare operation, a match or mismatch signal associated with each stored word is generated, indicating whether the search word matches a stored word or not.
A CAM stores data in a matrix of cells, which are generally either SRAM based cells or DRAM based cells. Until recently, SRAM based CAM cells have been most common because of their simple implementation. However, to provide ternary state CAMs, ie. where the search and compare operation returns a "0", "1" or "don't care" result, ternary state SRAM based cells typically require many more transistors than a DRAM based cells. As a result, ternary state SRAM based CAMs have a much lower packing density than ternary DRAM cells.
To provide the desired search and compare function in a DRAM or SRAM based CAM, matchline sensing circuits are required. Each matchline sensing circuit returns the appropriate state of its matchline, and the outputs of each matchline sensing circuit can be subsequently processed to determine the number of matches.
The circuit responsible for determining the existence of a match is the multiple match detection circuit. The multiple match detection circuit receives all the matchline sense circuit outputs as input signals after the search-and-compare operation, and determines one of two states. The first possible state represents the case where the search word does not match with any stored words or matches only one stored word. The second state occurs if the search word has matched with two or more stored words. The second state is significant because only one address of a matching word is returned as the resulting address of the search-and-compare operation. In such a case, if more than one match has resulted from the search-and-compare operation, there is at least one other stored word that matched the search word.
A prior art multiple match detection circuit and scheme is disclosed in commonly owned U.S. Pat. No. 6,307,798 titled Circuit and Method for Multiple Match Detection in Content Addressable Memory, filed Apr. 24, 2000, the contents of which are incorporated herein by reference. In the multiple match detection circuit of the prior art, a multiple matchline is precharged to a high voltage level, VDD for example, and subsequently discharged when there is at least one matchline sense circuit which outputs a signal indicating a match condition. There is one discharge transistor for each matchline sensing circuit output, and all discharge transistors are connected to the multiple matchline and in parallel with each other.
The multiple match detection circuit of the prior art compares the multiple matchline voltage level to a reference voltage during a sensing period in order to differentiate between the two different states. The reference voltage is fixed to mimic a multiple matchline having only one match, hence the multiple match detection circuit will sense if the multiple matchline voltage level is either above or below the reference voltage to generate the output corresponding to the first and second states respectively. The multiple match detection circuit therefore detects the discharged multiple match line to generate an output representing one of either the first and second states.
There are several disadvantages in the multiple match detection circuit and scheme of the prior art. To reduce the silicon area occupied by the multiple match detection circuit, it is desirable to minimize the feature size of the discharge transistors. Since the current strength of a transistor changes directly with its feature size, the capacity of a small discharge transistor to pull a fully precharged matchline to ground is small. This results in very slow discharge of the multiple matchline, and increases the time required for the overall search and compare operation of the CAM. Inherent parasitic capacitance of the multiple matchline compounds this problem, which increases as CAM arrays store more words, and require more discharge transistors.
The optimal sensing margin for the multiple match detection circuit should be sufficient for the circuit to easily distinguish if the multiple matchline potential level is above or below the reference voltage. This optimal sensing margin is attained at the time when the multiple matchline voltage level has decreased to a potential level well below the reference voltage. Unfortunately, the poor voltage discharge rate of the multiple matchline previously described only allows accurate sensing to be performed at a relatively prolonged time after the multiple matchline voltage begins to fall.
The multiple match detection circuit and scheme of the prior art requires precise timing control between activation of the matchline sense circuits, activation of the reference voltage generator circuit and activation of the sense circuit within the multiple match detection circuit. Each above-mentioned circuit is activated in sequence according to specific, preset time delays, which are determined from the design parameters and simulations. Process variations during fabrication of the CAM chip and different operating conditions may cause slight shifts in the time delays, resulting in a false output from the multiple match detection circuit.
There is clearly a need for a multiple match detection circuit capable of consuming very little power and detecting multiple matchline potential levels accurately at high speed.

Multiple match detection circuit and method


A duty cycle correction circuit and a delay locked loop circuit including the same are capable of reducing area and power consumption of a circuit. The delay locked loop circuit includes a delay locked loop unit, a delay controller, a duty cycle ratio correction circuit, and a duty cycle ratio detector. The delay locked loop unit outputs an internal clock by delaying an external clock in order to compensate a clock skew. The delay controller outputs a delay internal clock by delaying the internal clock in response to correction signals. The duty cycle ratio correction circuit outputs an internal correction clock by increasing or decreasing a high level section of the internal clock according to the correction signals. The duty cycle ratio detector outputs the correction signals in accordance with a duty cycle ratio of the internal correction clock.

The present invention relates to a duty cycle correction circuit and a delay locked loop circuit including the same, and more particularly to a delay locked loop circuit capable of reducing the area and power consumption of the circuit.
Generally, delay locked loop circuits refer to circuits which control the timing of data output from a memory device using a clock input from outside of the memory device, e.g., a synchronous semiconductor memory device.
In order to transmit output data from the memory device to a chip set without an error, the memory device and the chip set should be synchronized with the clock. However, because the internal circuit of the memory device delays the clock input from the chip set to the memory device, a phase difference occurs between an external clock input to the memory device and an internal clock of the memory device. The delay locked loop circuit compensates the phase difference between the external clock and the internal clock by removing a clock skew caused by the memory device's internal circuit.
Meanwhile, it is very important accurately to control the duty cycle ratio of the clock used in the memory device. The duty cycle ratio is the ratio of an interval occupied by a high level section and an interval occupied by a low level section during one clock cycle. For example, if the duty cycle ratio is 50:50, it means that the high level section occupies a time interval equal to that of the low level section during one clock cycle.
When the duty cycle ratio of the clock is not accurately controlled, the margin of data is not secured, so that the data may be distorted. Especially, because the data is input or output not only at the rising edge but also at the falling edge of the clock in Double Data Rate (DDR) synchronous semiconductor memory devices (SDRAM), the duty cycle ratio of the clock is more important in relation to the margin security of the data section in the DDR SDRAM. The duty cycle correction circuit corrects the duty cycle ratio of the clock to 50:50.
FIG. 1 is block diagram of a delay locked loop circuit including a conventional duty cycle correction circuit. Referring to FIG. 1, the conventional delay locked loop circuit includes a first delay locked loop unit 101, a second delay locked loop unit 131, and a duty cycle correction unit 151.
The first delay locked loop unit 101 includes a first phase comparator 103, a first delayer 105 and a first replica model 107. The second delay locked loop unit 131 includes a second phase comparator 133, a second delayer 135 and a second replica model 137. The duty cycle correction unit 151 includes a phase mixer 153 and a duty cycle ratio detector 155.
The first phase comparator 103 compares phases of an external clock EXT_CLK and a first feedback clock FB_1 output from the first replica model 107. The first replica model 107 includes a clock delay component in a semiconductor memory device, and outputs the first feedback clock FB_1 by receiving a first internal clock CLK_1. The phase comparison result CMP_1 is input to the first delayer 105. The first delayer 105 delays the external clock EXT_CLK by controlling the delay degree to match the phase of the first feedback clock FB_1 with that of the external clock EXT_CLK, thereby outputting the first internal clock CLK_1 which is delay-fixed.
The second delay locked loop unit 131 performs an operation similar to the first delay locked loop unit 101 to match a phase of a second feedback clock FB_2 with that of the external clock EXT_CLK, and outputs a second internal clock CLK_2 which is delay-fixed. The rising edges of the second internal clock CLK_2 and the first internal clock CLK_1 are phase-matched with each other. However, because the second delayer 135 reverses the external clock EXT_CLK, the duty cycle ratio of the second internal clock CLK_2 is opposite to the duty cycle ratio of the first internal clock CLK_1. A bubble on the output terminal of the second delayer 135 means the reversal of the phase. For example, if the duty cycle ratio of the first internal clock CLK_1 is 40:60, the duty cycle ratio of the second internal clock CLK_2 is 60:40.
The first internal clock CLK_1 and the second internal clock CLK_2 are input to the duty cycle correction unit 151. The duty cycle ratio detector 155 detects the duty cycle ratios of the first internal clock CLK_1 and the second internal clock CLK_2 to output a correction signal CRTL to the phase mixer 153.
The phase mixer 153 corrects the duty cycle ratios of the first internal clock CLK_1 and the second internal clock CLK_2 in response to the correction signal CRTL. The phase mixer 153 drives the first internal clock CLK_1 and the second internal clock CLK_2 with a driving force varied in accordance with the duty cycle ratios of the first internal clock CLK_1 and the second internal clock CLK_2, and mixes the phases of the first internal clock CLK_1 and the second internal clock CLK_2.
The phase mixer 153 may include a plurality of inverters, which are turned on or off in response to the correction signal CRTL to drive the first internal clock CLK_1 and the second internal clock CLK_2 with different driving forces, respectively. The more inverters that are turned on in response to the correction signal CRTL, the more strongly the first internal clock CLK_1 or the second internal clock CLK_2 is driven.
FIG. 2 is a diagram illustrating an operation of the phase mixer 153 in FIG. 1, which shows a high level section of the first internal clock CLK_1 and the second internal clock CLK_2.
The high level section of the first internal clock CLK_1 as described with reference to FIG. 2 is narrower than a low level section of the first internal clock CLK_1.
The phase mixer 153 drives the first internal clock CLK_1 and the second internal clock CLK_2 by controlling a driving force in response to the correction signal CRTL. When the second internal clock CLK_2 be driven more strongly than the first internal clock CLK_1, the falling edge of the output signal from the phase mixer 153 moves toward the falling edge side of the second internal clock CLK_2. When the first internal clock CLK_1 is driven more strongly than the second internal clock CLK_2, the falling edge of the output signal from the phase mixer 153 moves toward the falling edge side of the first internal clock CLK_1.
FIG. 3 is a timing diagram of the clock of the delay locked loop circuit in FIG. 1.
The duty cycle ratio of the external clock EXT_CLK is not 50:50. The high level section is narrower than the low level section. The first internal clock CLK_1 is generated by delaying the external clock EXT_CLK by a delay degree in response to a phase comparison result CMP_1 of the first phase comparator 103. Similarly, the second internal clock CLK_2 is generated by delaying the external clock EXT_CLK by a delay degree in response to a phase comparison result CMP_2 of the second phase comparator 133. The rising edge of the second internal clock CLK_2 phase-matches the rising edge of the first internal clock CLK_1, but the duty cycle ratio is the opposite.
Because the duty cycle ratio of the first internal clock CLK_1 is opposite to that of the second internal clock CLK_2, the duty cycle ratio detector 155 outputs the correction signal CRTL turning on inverters so that the number of inverters driving the first internal clock CLK_1 may be identical to the number of inverters driving the second internal clock CLK_2. The phase mixer 153 mixed phases of the first internal clock CLK_1 and the second internal clock CLK_2 by driving the first internal clock CLK_1 and the second internal clock CLK_2 using the turned-on inverters. Accordingly, each of duty cycle ratios of the output clocks OUT_1 and OUT_2 becomes 50:50.
As described above, because the conventional delay locked loop circuit corrects the duty cycle ratio by generating two clocks, two delay locked loop units are provided. Accordingly, the conventional delay locked loop circuit requires a greater circuit area, and consumes much power.

Duty cycle correction circuit and delay locked loop circuit including the same


The present invention teaches a fixation screw for securing a graft to a bone. The fixation screw is formed with a body member having a distal end, a proximal end, a central axis, and a cannula through the central axis of the body member. The body member also has a shank portion which is formed with an external screw thread, and a head portion rigidly coupled to the shank portion. The head portion is formed to mechanically couple with a driver and also to directly receive the graft which the fixation screw anchors.

This invention relates to an anchoring device for use in reconstructing torn ligament connections, such as the anterior cruciate ligament (ACL) in the knee. Specifically, this invention relates to an improved fixation screw, called an intra-articular tendon sling fixation screw by the inventor, which is formed as a unitary construct. The fixation screw has a threaded shank portion that can be inserted into bone and a head portion formed with an eyelet through which a graft, such as an autograft, an allograft or a prosthetic ligament, can be looped.
The fixation screw of the present invention is particularly suited for reconstructive surgery in which the fixation screw is preferably inserted completely into bone and directly receives the graft. As such, the present invention is particularly suited for ACL reconstruction and for posterior cruciate ligament (PCL) reconstruction in the knee. It is to be noted that ACL reconstruction has become a common operation. On the other hand, PCL reconstruction surgery is performed much less often as significant knee function can be maintained without the benefit of the PCL. Thus, for illustrative purposes, this specification will focus on ACL reconstruction surgery to illustrate the use, function and benefits of the present invention.
Reconstructive surgeries of the ACL date back as far as 1904. Since that time, a variety of different methods and devices for aiding in the reconstruction of the ACL have been patented and described. Most modern techniques utilize arthroscopic procedures to minimize the size of any incisions made. U.S. Pat. No. 5,374,269, granted to Thomas D. Rosenberg on Dec. 20, 1994 (hereinafter referred to as Rosenberg '269) is illustrative of the prior art. Rosenberg '269 describes variations on a number of common techniques of ACL reconstruction.
Rosenberg '269 specifically claims a method of forming a passageway in a femur at the knee joint. Its specification does not limit itself, however, to only describing this specific sub-procedure. Rosenberg '269 describes two ACL reconstruction methods that use the patellar tendon as the graft and one method that uses the semitendinosus tendon. Both the patellar tendon and the semitendinosus tendon can be harvested from the individual having the knee surgery and are, therefore, autografts. These tendons are commonly used as the replacement graft for the torn or ruptured ACL. In each of the methods described in Rosenberg '269, tunnels are drilled in the tibia and the femur. These tunnels end in the intra-articular space of the joint at the attachment sites of the torn or ruptured ACL. The tunnel in the tibia goes from the tibial cortex at a site between 20 and 25 mm below the knee joint to the intra-articular space of the knee joint. The tunnel in the femur is a closed-end tunnel, although it may be formed with a channel that extends to the lateral surface of the femur, depending on the graft attachment method used. Rosenberg '269 modifies the prior art method of drilling the femoral tunnel, but is otherwise indicative of an accepted practice for forming the femoral and tibial tunnels.
In Rosenberg '269, the graft, whether a patellar tendon or a semitendinosus tendon, is implanted with one end secured in the closed-end femoral tunnel and the other end secured in the tibial tunnel or at a point adjacent to the tibial tunnel on the tibial cortex.
In the first method described by Rosenberg '269, using the patellar tendon, the bone plug on the leading end of the graft can be locked in place in the femoral tunnel with an interference screw. Rosenberg '269 also teaches a method by which the leading end bone plug is attached with sutures that are anchored to the lateral femoral cortex by means of a button. The sutures pass through a channel that extends from the closed end of the femoral tunnel to the lateral surface of the femur. The sutures attach to the leading bone plug. In both methods using the patellar tendon, the trailing bone plug is secured by staples to the tibial cortex below the tibial tunnel entrance.
Rosenberg '269 also describes a method for anchoring the semitendinosus tendon. Elongated sutures are attached to the ends of the semitendinosus tendon graft. The leading end of the graft is secured in a manner similar to the second method for securing the patellar tendon in the femoral tunnel described above. That is by means of sutures attached to a button on the lateral femur cortex, which are passed through a channel to the end of the femoral tunnel where they attach to the semitendinosus graft. The trailing edge of the graft is secured in the tibial tunnel by means of sutures that are affixed to a screw or post positioned on the tibia adjacent to the entrance of the tibial tunnel.
While the methods of preparing tunnels in the bones of the knee joint taught by Rosenberg '269 are applicable to methods using the present invention, the present device differs materially from any device taught in Rosenberg '269. The fixation screw of the present invention is an anchor. Rosenberg '269 teaches an interference screw. Furthermore, use of the fixation screw of the present invention requires vastly differing attachment methods for grafts than the methods taught by Rosenberg '269. First, the inventor prefers not to use the patellar tendon as a graft for ACL reconstruction. Second, when the fixation screw of the present invention is used with the semitendinosus tendon, there is no need to form a channel from the closed-end tunnel in the femur to the surface of the femoral cortex, nor is there a need to make a lateral incision at the lateral femoral cortex as is necessary with the method described by Rosenberg '269. Thus, methods employing the present invention reduce the number of incisions made and trauma to the femur or other bone in which the fixation screw is inserted. They also do not require the use of sutures for anchoring the leading end of the semitendinosus tendon in the femoral tunnel.
While the present invention differs from the devices and methods taught by Rosenberg '269 in both form and use, two endosteal ligament retaining devices have been described that are more similar to the present invention in the methods by which they anchor a graft in the femur. They are U.S. Pat. No. 5,129,902, entitled "Endosteal Ligament Retainer," granted to E. Marlowe Goble and Karl Somers on Jul. 14, 1992 (hereinafter referred to as Goble '902) and U.S. Pat. No. 5,152,790, entitled "Ligament Reconstruction Graft Anchor Apparatus," granted to Thomas D. Rosenberg, Gerard S. Carlozzi and William J. Reimels on Oct. 6 , 1992 (hereinafter referred to as Rosenberg '790). Like the present invention, these inventions teach an anchor inserted into a closed-end femoral tunnel that receives a graft. Also like the present invention, both of these devices are used in methods where the closed-end femoral tunnel is formed in the femur in a fashion similar to Rosenberg '269. However, like the method for which the present invention is designed and unlike Rosenberg '269, these methods and devices do not need a channel formed in the femur that passes from the closed-end tunnel to the lateral femoral cortex.
Goble '902 teaches an anchor consisting of a basket or disk for receiving a graft which is rotatably attached to a screw. The graft receiving disk or basket is able to spin on the screw head, preventing the graft from twisting or rotating as the screw is driven into the closed end of the femoral tunnel. The graft can either be looped through an opening in the basket or sutured to the basket.
Rosenberg '790 also teaches an anchor assembly consisting of a basket, called a ring in this case, for receiving the graft which is rotatably attached to a threaded body member. Like Goble '902, the graft receiving basket is able to spin on the threaded body member. Rosenberg '790, however, teaches suturing the graft to the ring.
There are a number of material differences between the prior art and the present invention. Both Goble '902 and Rosenberg '790 are multi-component anchors having moving parts. This can lead to complications. Furthermore, because the diameter of the basket of Goble '902 is much larger than the threads of the fixation screw, it could become wedged against the edge or side of the femoral tunnel during installation, making it difficult to fully insert or retrieve the anchor. It is to be noted that both Goble '902 and Rosenberg '790 teach using sutures as an intermediate means for attaching the graft to the anchor. The sutures are the weak link in the attachment and suture breakage is a consideration. Also, neither of the prior art devices are cannulated for use with a guide drill. Finally, in both Goble '902 and Rosenberg '790, because the means for attachment of the graft are located away from the central axis of the anchor or threaded member, the graft cannot be aligned with the axis of the anchor member, either during or after installation.
Furthermore, in Goble '902, when sutures are not used to attach the graft to the basket, the graft can end up being pinched between the basket and the wall of the femoral tunnel. This is because the graft or grafts must loop through openings in the arcuate walls of the basket on its periphery.
To summarize, the present invention provides a fixation screw that has no moving parts, that can be installed in a closed-end femoral tunnel with the use of a guide drill, receive a graft without the necessity of sutures, receive a graft without causing pinching of the graft between the fixation screw and the wall of the femoral tunnel, and that allows the anchored graft to be aligned with the central axis of the fixation screw.

Intra-articular tendon sling fixation screw