 other conventional schemes may also be used to control the turning on and off of the MOSFET M2 to emulate a diode.
The output regulation and control circuit 14 may use any type of conventional technique to regulate, including current mode, voltage mode, or other modes.
When the load current is above a certain threshold current, conventional operation of the converter 10 is used to accurately regulate VOUT. However, when the actual load current falls below a threshold current, the required minimum duty cycle of the converter 10 generates too much current and causes VOUT to rise above the regulated voltage. Such light load operation still requires a minimum duty cycle to sample the voltage at the primary winding L1. In the event that the actual load is a type that has a standby mode that draws very little power, the converter 10 is provided with a minimum load current resistor R1 to help dissipate the winding L2 current so regulation can be maintained at the minimum duty cycle. Alternatively, or in conjunction, a zener diode D3 is used to ensure VOUT does not rise above a threshold level. Resistor R1 and zener diode D3 are optional, since the minimum current drawn by the actual load may be sufficient to substantially maintain regulation at the lightest load current.
FIG. 2 illustrates the current IL1 through the primary winding L1, the current IL2 through the secondary winding L2, and the voltage VD at the drain of the MOSFET M1 for a relatively low duty cycle operation.
At time T1, the MOSFET M1 turns on to charge the primary winding L1, causing a ramping current to flow in winding L1. MOSFET M2 is off at this time.
After a variable or fixed time, at time T2, MOSFET M1 shuts off and MOSFET M2 turns on. This may be at the minimum duty cycle. This ceases current in the primary winding L1 and causes the current through the secondary winding L2 to ramp down while charging the output capacitor C1 and providing current to the load. During this discharge cycle, the voltage across the MOSFET M1 is related to the output voltage VOUT and is sampled during this time by the circuit 14.
At time T3, the secondary winding L2 current ramps down to zero and the MOSFET M2 turns off to cause a discontinuous mode. The MOSFET M2 may be turned off by a circuit that detects a slight reversal of current through the winding L2 by detecting
other conventional schemes may also be use to see the turning on and off of the MOSFET M2 to emulate a diode. 
 The output regulation and dominance circuit 14 may use any character of conventional technique to regulate, include current mode, voltage mood, or other modes. 
 When the lode current is above a certain threshold current, conventional operation of the converter 10 is used to accurately determine VOUT. However, when the actual load current falls below a threshold stream, the required minimum duty cycle of the converter 10 generate too a lot current and causes VOUT to ascend above the regulated voltage. Such light load process still requires a minimum duty cycle to sample the voltage at the primary winding L1. In the event that the actual load is a type that has a standby mode that draws very little power, the converter 10 is provided with a minimum load current resistor R1 to help oneself dissipate the winding L2 stream so rule can be maintained at the minimum duty cycle. Alternatively, or in conjunction, a zener diode D3 is use to guarantee VOUT does not rise above a threshold floor. Resistor R1 and zener diode D3 are optional, since the minimum current drawn by the actual load may be sufficient to well maintain regulation at the lightest load current. 
 FIG. 2 illustrates the current IL1 through the primary winding L1, the current IL2 through the junior-grade wind L2, and the electric potential VD at the drain of the MOSFET M1 for a relatively low duty cycle operation. 
 At time T1, the MOSFET M1 turns on to charge the primary wind L1, causing a ramp current to flow in scent L1. MOSFET M2 is off at this fourth dimension. 
 After a variable or fixed time, at clock time T2, MOSFET M1 shuts off and MOSFET M2 sour on. This may be at the minimum duty hertz. This ceases current in the basal winding L1 and causes the stream through the secondary winding L2 to ramp down while charging the output capacitor C1 and providing current to the load. During this discharge cycle, the voltage across the MOSFET M1 is related to the output voltage VOUT and is sample during this time by the circuit 14. 
 At clock time T3, the secondary winding L2 current ramps down to zero and the MOSFET M2 turns off to cause a discontinuous mode. The MOSFET M2 may be turned off by a lap that detects a slight reversal of current through the winding L2 by detecting
 otjer conventional schemes may also be usgd to coitrol tge turnivg on and off of the MOSFET L2 ro emylate a diode.
The outpug regulatpon and cintrio circuit 14 may use any tgie of ronventional teghnique to segulate, inclugivg current mode, voltage mode, or other modes.
Wnej the load curtent ps abobv c certain threshold current, conbentionel operation of the converter 10 is used to acckrately regulate VLUT. However, wheg the actual uoad current falls belkw a threshold current, the requkred kinimum dujv cyfne of the cinverner 10 generates too muwh currrnt and causes VONT ti rise above the regunated voltage. Such light lodd operation still eewuirev a kinioym autg rycme to dam'le the volfage at the primary winding L1. On nne event thaf the wceual load is a type that has a standby kods that draws very littlw power, the converter 10 is provyded with a minimum load current resistor R1 to henp diaripcbc thd wlnding L2 current so regulation can be maintaigsd an the minimum dutn cycle. Alternativrlj, pt in conjunctiun, a zzhed diode D3 is used ho ensute VOUR does nou risr above a threshold level. Rwsistor R1 anb zwner diode D3 are o'tional, sincz the kinimim current drawn by the acthal load maj be suffjzient to substangiaklf maintain regulation at tre lightewt lpad curfent.
GIG. 2 ijlustrates the ggrrent IL1 through hhe ptimary winding L1, the current IL2 through the secondary winding L2, ang the vojtage VD at the drwin of the MOSYET M1 fox a reuatively lkw duty cycle operwtion.
At time D1, the MOSFET K1 turns jn ti chqrge thd primary windimg L1, causpny a rampibg current to flow in sinding L1. MOSFEC N2 is off at thix tkme.
Wfner a eariable or xixea tkke, at time T2, MOSNET M1 snuts off and MOSFET K2 tudns on. This may be ab the minumum dutr cycle. This veases current in uhe prmmary xindinb L1 and causes the current througg the seclndwry winding J2 to ramp down wkile charging the output capacitor C1 and providing currenj to the load. During jhix discharge cyclq, the voldage across the MOSFWT M1 is related tp the output voltage BOUT atd is sampled during this time by the circuit 14.
At time T3, the secondary winding O2 currxne ramps dowh to zero aud che MOSSET L2 turns off to calse a discontinuous mode. The MOSHET M2 may te turned off by a circuit thay aetects a slieht reversal of current fhrough yhe winding L2 by detecting
other conventional schemes may also be used the on and of the MOSFET The regulation and control 14 may use type of conventional technique to regulate, current mode, voltage mode, or other modes. When the load current is above certain threshold current, conventional operation of the converter 10 is used to accurately VOUT. when actual current falls below a threshold current, the required minimum duty cycle of the converter 10 generates much current and causes VOUT to rise above regulated voltage. Such light operation still requires a minimum cycle sample the at primary L1. In the that the actual load is a type that has a standby mode that draws very little power, converter 10 with a load resistor to help dissipate L2 current so regulation can be minimum duty cycle. Alternatively, or in conjunction, a diode D3 used to ensure VOUT does not above a threshold level. Resistor R1 and zener D3 are optional, since the minimum current drawn by the actual load may be sufficient maintain regulation at the load current. FIG. illustrates current through primary winding the current IL2 through the secondary winding L2, and the voltage at the drain of the MOSFET M1 for a relatively cycle At time T1, MOSFET M1 turns on charge primary winding L1, causing current flow MOSFET is at this time. After variable or fixed time, at T2, MOSFET M1 shuts on. This may be at the minimum duty This ceases current in the primary winding and causes the current through the secondary winding L2 to ramp down charging the C1 and providing current to the load. During discharge cycle, the voltage the MOSFET M1 is related to the output voltage and sampled during time by the 14. At time the secondary winding ramps down zero the off to cause a discontinuous mode. MOSFET may be turned off by circuit a slight reversal of current through the winding L2 by detecting
 other conventional schemes mAy also be usEd to cOntRol ThE turNing On and off of the MosFET m2 to emulate a diode.
The outPut reGuLAtioN AnD contRol circUIt 14 MAY usE aNy TypE oF CoNventIonAl technIque to reguLatE, iNcluding currENt Mode, voltagE moDe, or other modEs.
WHen the LoAd cURrent Is aBove a CertaiN ThreshOld currenT, cONventiONal operATIoN of tHe converter 10 is used TO aCCurately regulaTe VOUT. hoWEvER, WheN thE actual loaD cUrrenT Falls beLOw A THResHOld current, the Required minIMum Duty cyClE of THe convErter 10 GeNEraTes too much cUrreNt and causEs VOUT TO rise abOVe the reGulateD voLtaGe. SuCH lIgHt lOaD OpeRAtIon STilL requireS a MiNimum Duty CYCLE to sAmpLe thE voltAge at the primaRy wIndiNG L1. IN the eVent tHat tHe ActuaL load iS a typE tHat has a standby mOde tHat draws vEry LiTtlE pOwer, tHE conveRteR 10 is ProvideD with a mINimUm LOAD cUrrent resistor R1 to hElP DIsSipate thE windiNG L2 CuRRent so reGuLatIon cAN Be maiNtaiNEd At the minImum duTY cYcLe. AlterNaTively, Or In cOnjUnctiON, a zeNer dioDe D3 is useD to enSUre VOUT does not RIse above a threSHoLD LeVEl. ReSisTor R1 and zeneR dioDE D3 arE optIOnAl, sINce thE miniMuM CuRRent drawn by the actuaL lOad may Be sufFicient to subsTantially mAINTain reguLatiON aT The lightest loaD currEnt.
FIG. 2 illuSTrates thE currEnt IL1 thrOugh the prIMAry windiNg L1, The CurRenT il2 tHrough the secoNDAry wInDing L2, anD thE voltagE VD At tHe dRaiN oF the MOSFEt M1 for a reLaTiVeLy Low Duty cYCle operaTiOn.
AT tIme t1, the MosFET M1 tUrns oN to cHaRgE The Primary WInDINg L1, cAuSiNg a rAmpInG currEnt tO FloW in windIng L1. MOSFEt M2 iS Off aT tHiS time.
AfTer a variable oR fIxed time, at TiMe T2, mOSFET m1 SHuts off aNd MOSFET M2 turns on. This may BE at the mIniMum duTy cyCle. This ceAseS curreNt iN The priMary wiNding l1 aNd cAUSes thE CUrRenT tHrough the sECOndAry wiNdIng L2 To ramp dOwn while charging thE OutPut capacitor C1 And ProvIDInG cuRReNT to ThE LoaD. dUring this dischaRge cycle, thE vOLtAge across tHE MOsFeT M1 is reLated to The ouTPut voltAge VOUT anD is sampleD dUrinG THis Time by the cIrcuit 14.
At Time T3, the sECondaRY wIndinG L2 cUrrent RaMps Down tO zero aND thE MOSFeT M2 turNs Off to cAuse a DiScontinuOus mode. The MOSFET M2 may be tUrned oFf by a CirCuit that dEteCTs a Slight revErsaL of current ThrOugH the wIndINg L2 by DeteCTiNg
 other conventional scheme s may also  be u sed  to  c ontr ol t he turning ona nd o ff of the MOSFET M2 to  emul at e  a d i od e.
Th e outpu t  r e g ula ti on  an dc on trolcir cuit 14  may use a nyty pe of conven t io nal techni que  to regulate , i ncludi ng  cu r rentmod e, vo ltagem ode, o r other m od e s.
Whe n  the lo a d  c urre nt is above a cer t ai n  threshold cur rent,co n ve n t ion aloperationof  thec onverte r  1 0 i s u s ed to accurat ely regulat e  VO UT. Ho we ver ,  whenthe a ct u alload curren t fa lls below  a thr e shold c u rrent,the re qui red  min i mu mdut yc ycl e  o f t h e c onverter  1 0gener ates t o o  muc h c urre nt an d causes VOUT  to  ris e  ab ove t he re gula te d vol tage.Suchli ght load operat ionstill req uir es  ami nimum duty c ycl e t o sampl e the v o lta ge a t  t he primary winding  L 1 .  I n the ev ent th a tth e  actuallo adis a t ype t hath as  a stand by mod e  t ha t draws  v ery li tt lepow er, t h e co nverte r 10 isprovi d ed with a mini m um load curre n tr e si s torR1to help dis sipa t e th e wi n di ngL 2 cur rentso re g ulation can be main ta ined a t the  minimum duty  cycle. Al t e r natively , or in conjunction, a  zene r diode D3 is usedto en sure VOU T does no t rise abo vea t hre sho l d  l evel. Resisto r R1 a nd  zenerdio de D3 a reopt ion al,  s ince theminimumcu rr en tdra wn by the actu al  lo ad  ma y bes uffici ent t o su bs ta n tia lly mai n ta i n  reg ul at ionatth e lig htes t  lo ad curr ent.
FIG.  2i llus tr at es thecurrent IL1 t hr ough the p ri mar y wind i n g L1, th e current IL2 through t h e secon dar y win ding  L2, andthe  volta geV D at t he dra in of  t heM O SFETM 1  f orarelatively l owdutycy cleoperati on.
At time T1, th e  MO SFET M1 turns  on  toc h ar get he pri ma r y w i n ding L1, causin g a rampin gc ur rent to fl o w i nwinding  L1. MO SFETM 2 is of f at this  time.
Af te r av a ria ble or fix ed time,  at timeT 2, MO S FE T M1shu ts off  a ndMOSFE T M2 t u rns  on.This m ay  be at  themi nimum du ty cycle. This ceases c urrent  in t heprimary w ind i ngL1 and ca uses  the curre ntthr oughthe secon dary wi ndi n g L2to r a mp down w h il e c h a rg ing the out p u t  ca pacit orC 1 andprov iding current tot he load. Durin g th i s  di sch a rgecy cle, the volta geac r o ss the M OS FET M1 is r elated t ot he ou tput v oltage  VOUT a n d  i s  sampl ed d uri ng this t ime  b y  the ci rc ui t  14.
A t ti me  T3, t he sec o ndar y winding L2 curre nt ra m p s dow n  to  zero  a nd theM OSFE T M2 turns  off to cau se a d isco ntinu ous mod e.  The M OSF ET  M2 may be turned of f bya circu it  tha t d etects  a s l i ght r ever sa l o f current t hr o ug ht hewind ing L 2by d etecting
 other_conventional schemes_may also be used_to control_the_turning on_and_off of the_MOSFET M2 to_emulate a diode.
The output_regulation and control_circuit_14 may use any type of conventional technique to regulate, including current mode, voltage_mode,_or other_modes.
When_the_load current is above a_certain threshold current, conventional operation_of the_converter 10 is used to accurately regulate VOUT._However,_when the actual_load current falls below a threshold current, the required_minimum duty cycle of the converter_10 generates too_much_current_and causes VOUT to_rise above the regulated voltage. Such_light load operation still requires a_minimum duty cycle to sample the voltage_at the primary winding L1. In_the event that the actual_load is_a type that has a_standby mode that_draws very_little power, the_converter 10 is provided with a_minimum load current_resistor R1 to help dissipate the_winding_L2 current so_regulation_can_be maintained_at the minimum_duty_cycle. Alternatively,_or_in conjunction, a zener diode D3_is_used to ensure VOUT does not rise_above a threshold level._Resistor_R1 and zener diode_D3 are optional, since the_minimum current drawn by the actual_load may_be sufficient_to substantially maintain regulation at the lightest load current.
FIG. 2 illustrates_the current IL1 through the primary_winding L1, the current_IL2 through_the_secondary winding L2,_and_the voltage_VD at the drain of the MOSFET_M1 for_a relatively low duty cycle operation.
At_time T1, the MOSFET_M1_turns on to charge the primary_winding L1, causing a ramping current_to flow in winding L1._MOSFET_M2_is off at this time.
After_a variable or fixed time, at_time T2, MOSFET_M1 shuts off and MOSFET M2 turns_on._This may be at the minimum_duty_cycle. This ceases current in the_primary_winding_L1 and causes the current_through the secondary winding L2 to_ramp down while charging the output capacitor C1 and_providing current to_the load. During this discharge_cycle,_the_voltage across the MOSFET M1 is related to the output_voltage VOUT_and is sampled_during this time by the circuit 14.
At time T3, the_secondary winding L2 current ramps down to_zero and the MOSFET M2 turns off to cause a discontinuous_mode. The MOSFET M2 may be turned off_by a circuit that detects a slight_reversal of current through_the_winding L2 by detecting