CN205249038U - Drive and control circuit and switching power supply - Google Patents

Abstract

The utility model provides a drive and control circuit and switching power supply. Drive and control circuit is used for control compensation electric capacity and switch tube, drive and control circuit includes: the sample and hold module, its the reference signal who generates in the initial on off cycle of the one or more of switch tube and keep being inversely proportional to with power conversion circuit's input voltage, and first comparator, its receive by sample and hold module create reference signal and with the detected signal that the offset voltage at building -out capacitor both ends was directly proportional the detected signal is less than output set signal is with right during reference signal the building -out capacitor charges, and the detected signal is more than or equal to to relieve the set signal right in order to stop in output during reference signal the building -out capacitor charges.

Description

Drive and Control Circuit and Switching Power Supply

Technical field

The utility model relates to field of switch power, relates in particular to Drive and Control Circuit and Switching Power Supply.

Background technology

High Power Factor drive system is by PFC (PFC) control circuit gauge tap pipe (exampleAs transistor, FET, controllable silicon thyratron etc.) turn-on and turn-off maintain burning voltage or electric currentA kind of power supply of output, is also referred to as PFC control system, and for example Switching Power Supply, LED illumination drive electricitySource etc.

At present for the constant-current drive circuit of high PFC, be no matter buck configuration, buck structure orBe inverse-excitation type structure etc., in order to obtain high PFC, general employing fixed ON time control, simultaneously in order to obtainObtain good constant current accuracy and generally adopt closed-loop control. Therefore the common ground of these power supplys is exactly to driveThe additional building-out capacitor C of chip COMP pin_COMPCarry out the power frequency component of filtering input voltage vin, therebyRealize ON time T within the input voltage vin half period_ONConstant.

The ON time T of these power supply architectures in the time of normal work_ONThat the voltage of being held by COMP determines:

T_ON＝K1×V_COMP(1)

Due to building-out capacitor C_COMPLarger, the loop response speed of system is very slow, and therefore these power supplys are depositedA common issue be exactly system building-out capacitor C while starting_COMPThe problem of set.

General in system boot, need to be to building-out capacitor C_COMPPre-charged set, if not rightBuilding-out capacitor C_COMPCharging set and just by loop control, system there will be and cannot start or repeatedlyThe problem of repeated priming. If but to building-out capacitor C_COMPSet is too high, and system there will be startupThe problem of overshoot. Therefore in general power circuit, there is building-out capacitor C_COMPSetting circuit, as shown in Figure 1.Its principle is in the time starting, COMP terminal voltage V_COMPBe less than predetermined reference voltage V0, comparator 101Output asserts signal disconnects switch S 1, and current source 102 is held capacitor C by triode Q1 to COMP_COMPThe set of charging. As COMP terminal voltage V_COMPAfter reaching preset value V0, comparator 101 defeatedGo out signal upset (become and remove asserts signal), make switch S 1 closure, thereby triode Q1 is turn-offed,Finish COMP end capacitor C_COMPCharging set. Because V0 is fixed value, therefore COMP endSet voltage V_COMPFix.

For the LED constant-current drive circuit of high PFC constant on-time, due to different input voltagesThe normal work bucking voltage V that Vin is corresponding_COMPDifferent, when input voltage vin is low, compensation electricityPress V_COMPHigh; When input voltage vin is high, bucking voltage V_COMPLow. So just there will be when input electricityWhile pressing Vin high, capacitor C_COMPSet is suitable, and input voltage vin is when low, system can cannot start orPerson is the situation of repeated priming repeatedly; Or when input voltage vin is low, capacitor C_COMPSet is suitable, and defeatedEnter voltage Vin when high system can start the situation of overshoot.

In addition for different switch power supply systems, due to inductance value L and the sampling resistor R of transformer_SNoWith, while normally work, bucking voltage is also different, above-mentioned fixing building-out capacitor C_COMPSet is difficult toAdapt to different systems.

Therefore, the utility model needs improved Drive and Control Circuit and Switching Power Supply.

Utility model content

For needing above, the utility model proposes a kind of Drive and Control Circuit and drive control method, energyEnough different input voltage vin and different systems of automatically adapting to require to building-out capacitor C_COMPCarry out set,To promote that different system can normally start in different input voltage vin situations, there will not be and cannot startOr the repeatedly problem of repeated priming or startup overshoot.

According to an embodiment of the present utility model, provide a kind of Drive and Control Circuit, described driving controlCircuit is for control and compensation electric capacity and switching tube, and described Drive and Control Circuit comprises: sampling keeps module, itsIn one or more initial switch cycle of described switching tube, generation maintenance and circuit for power conversion is defeatedEnter the reference signal that voltage is inversely proportional to; And first comparator, it receives by described sampling and keeps module to generateDescribed reference signal and the detection signal being directly proportional to the bucking voltage at described building-out capacitor two ends, in instituteState when detection signal is less than described reference signal and export asserts signal so that described building-out capacitor is charged, andIn the time that described detection signal is more than or equal to described reference signal, output is removed asserts signal to stop describedBuilding-out capacitor charges.

In one aspect, described Drive and Control Circuit also comprises: the first current source, it is connected to described compensationElectric capacity; And first switch, it is connected between described current source and ground connection, and described the first switch is describedWhen the first comparator output asserts signal, disconnect so that described the first current source charges to described building-out capacitor, andAnd described the first switch is closed so that described the first electricity in the time that asserts signal is removed in described the first comparator outputStream source stops described building-out capacitor charging.

In one aspect, described Drive and Control Circuit also comprises: be connected to described the first current source and described benefitRepay the triode between electric capacity.

In one aspect, described Drive and Control Circuit also comprises: the second comparator, it is at described switching tubeIn one or more initial switch cycles, receive sampled voltage and the pre-set peak value of described circuit for power conversion, andIn the time that described sampled voltage is more than or equal to described pre-set peak value, export the first cut-off signals opens described in turn-offingGuan Guan; And ON time control module, its follow-up after described one or more initial switch cyclesIn work period, receive bucking voltage and the sawtooth signal at described building-out capacitor two ends, and at described sawtoothWhen being more than or equal to described bucking voltage, exports ripple signal the second cut-off signals to turn-off described switching tube.

In one aspect, described ON time control module comprises: saw-toothed wave generator, its generation has in advanceThe sawtooth waveforms of fixed cycle; The 3rd comparator, its receive described building-out capacitor two ends bucking voltage and described inSawtooth waveforms, and in the time that described sawtooth waveforms is more than or equal to described bucking voltage, export described the second cut-off signals.

In one aspect, described ON time control module comprises: the second current source; And described in being connected toThe charge and discharge capacitance of the second current source, described charge and discharge capacitance in the time of described switching tube conducting by described the second electricityThe charging of stream source, and electric discharge in the time that described switching tube turn-offs, wherein said sawtooth waveforms is described charge and discharge capacitance twoThe voltage of end.

In one aspect, described Drive and Control Circuit also comprises: driver module, its output drive signal is to leadLogical or turn-off described switching tube; And second switch, it is in one or more initial switch of described switching tubeIn cycle, the output of described the second comparator is connected to described driver module, and described one or more at the beginning ofIn the follow-up work cycle after beginning switch periods, the output of described ON time control module is connected to instituteState driver module.

In one aspect, described Drive and Control Circuit also comprises: rest-set flip-flop, it is connected to described secondBetween switch and described driver module, described rest-set flip-flop receives by described second via described second switchThe first or second cut-off signals of comparator or described ON time control module output to described driving mouldPiece provides cut-off signals to turn-off described switching tube.

In one aspect, described Drive and Control Circuit also comprises: the 4th comparator, it receives described power and turnsChange the feedback voltage signal of circuit, and export conducting during lower than predetermined threshold value voltage at described feedback voltage signalSignal, described rest-set flip-flop receives described Continuity signal and described Continuity signal is offered to described driving mouldPiece is with switching tube described in conducting.

In one aspect, described sampling keeps module to be connected in described one or more initial switch cyclesDescribed rest-set flip-flop is to sample and to keep the time span of described rest-set flip-flop output Continuity signal as instituteState reference signal.

In one aspect, described Drive and Control Circuit also comprises: ON time detection module, it is described oneIn the follow-up work cycle after individual or multiple initial switch cycles, be connected to described rest-set flip-flop to detect instituteState the time span of rest-set flip-flop output Continuity signal as described detection signal.

According to an embodiment of the present utility model, a kind of Switching Power Supply is provided, comprising: as aboveDrive and Control Circuit; Described circuit for power conversion, for converting input voltage to output voltage; Be connected toThe described switching tube of described circuit for power conversion; And the described compensation that is connected to described Drive and Control Circuit is electricHold.

In one aspect, described Switching Power Supply also comprises the feedback of the output that is connected to described circuit for power conversionResistor network is to provide the feedback voltage signal of described circuit for power conversion.

In one aspect, described Switching Power Supply also comprises that the sampling resistor of connecting with described switching tube is to provideState the sampled voltage of circuit for power conversion.

In one aspect, described Switching Power Supply comprise inverse-excitation type switch power-supply, step-down/up type Switching Power Supply orAt least one in step down switching regulator.

According to an embodiment of the present utility model, provide a kind of driving control method, described driving controlMethod is for control and compensation electric capacity and switching tube, and described driving control method comprises: at one of described switching tubeThe ginseng that in individual or multiple initial switch cycles, the input voltage of generation maintenance and circuit for power conversion is inversely proportional toExamine signal; And receive described reference signal and be directly proportional to the bucking voltage at described building-out capacitor two endsDetection signal is exported asserts signal with electric to described compensation in the time that described detection signal is less than described reference signalHold and charge, and asserts signal is removed in output in the time that described detection signal is more than or equal to described reference signalDescribed building-out capacitor is charged stopping.

In one aspect, described driving control method also comprises: one or more initial at described switching tubeIn switch periods, receive sampled voltage and the pre-set peak value of described circuit for power conversion, and at described sampled voltageWhile being more than or equal to described pre-set peak value, export the first cut-off signals to turn-off described switching tube; And describedIn the follow-up work cycle after one or more initial switch cycles, receive the benefit at described building-out capacitor two endsRepay voltage and sawtooth signal, and export in the time that described sawtooth signal is more than or equal to described bucking voltageThe second cut-off signals is to turn-off described switching tube.

In one aspect, described driving control method also comprises: in the time of described switching tube conducting to discharging and recharging electricityHold and charge, and in the time that described switching tube turn-offs, described charge and discharge capacitance is discharged, wherein said sawTooth ripple is the voltage at described charge and discharge capacitance two ends.

In one aspect, described driving control method also comprises: one or more initial at described switching tubeIn switch periods, turn-off described switching tube with described the first cut-off signals; And described one or moreIn the follow-up work cycle after the initial switch cycle, turn-off described switch with described the second cut-off signalsPipe.

In one aspect, described driving control method also comprises: the feedback electricity that receives described circuit for power conversionPress signal, and export Continuity signal with described in conducting at described feedback voltage signal during lower than predetermined threshold value voltageSwitching tube.

In one aspect, described driving control method also comprises: in described one or more initial switch cyclesMiddle sampling also keeps the time span of described Continuity signal as described reference signal.

In one aspect, described driving control method also comprises: in described one or more initial switch cyclesIn the follow-up work cycle afterwards, detect the time span of described Continuity signal as described detection signal.

Brief description of the drawings

Fig. 1 is the circuit diagram for building-out capacitor set according to prior art.

Fig. 2 is according to the circuit diagram of the switch power supply system of an embodiment of the utility model.

Fig. 3 A is according to the circuit diagram of the Drive and Control Circuit of an embodiment of the utility model.

Fig. 3 B is according to the circuit diagram of the Drive and Control Circuit of another embodiment of the utility model.

Fig. 4 is according to the circuit diagram of the inverse-excitation type switch power-supply of an embodiment of the utility model.

Fig. 5 is according to the circuit diagram of the step-down/up type Switching Power Supply of an embodiment of the utility model.

Fig. 6 is according to the circuit diagram of the step down switching regulator of an embodiment of the utility model.

Detailed description of the invention

Below in conjunction with specific embodiments and the drawings, the utility model is described in further detail, but should not limit with thisProtection domain of the present utility model.

Fig. 2 is that it comprises according to the circuit diagram of the switch power supply system of an embodiment of the utility modelCircuit for power conversion 210, Drive and Control Circuit 220, switching tube (for example metal-oxide-semiconductor) M1, sampling electricityResistance Rs, feedback resistive network R2 and R3 and building-out capacitor C_COMP. Circuit for power conversion 210 canTo can be used for converting current/voltage Vin to required target current/voltage Vout any suitableCircuit for power conversion, such as transformer, inductance etc. Vout can be (as negative in LED lamp or other to loadCarry) power supply. Drive and Control Circuit 220 can be carried by input voltage vin or other chip voltages at Vcc pinFor starting resistor. Drive and Control Circuit 220 on DR pin output drive signal with gauge tap pipe M1Turn-on and turn-off, thereby the duty of power ratio control change-over circuit 210. Drive and Control Circuit 220 is logicalCrossing magnitude of voltage that CS pin (, sampling end) detects sampling resistor Rs determines and flows through switching tube M1'sCurrent signal, thus in the time of normal work, can detect to reach by sampling end the order of current limliting or obtaining current. The COMP pin of Drive and Control Circuit 220 connects building-out capacitor C_COMPWith filtering input voltage vinPower frequency component, thereby realize the conducting of switching tube M1 within the input voltage vin half period in normal workTime T_ONConstant.

According to an embodiment of the present utility model, in one or more initially the opening of switch power supply system startupIn the cycle of pass, in the time of switching tube M1 conducting, sampled signal CS increases gradually, when sampled signal CS increasesDuring to predetermined threshold, Drive and Control Circuit 220 outputs are used to indicate the cut-off signals of on-off switching tube M1.In the time that switching tube M1 turn-offs, feedback signal FB reduces gradually, when feedback signal FB (example during lower than threshold valueAs, when zero passage), Drive and Control Circuit 220 outputs are used to indicate the Continuity signal of actuating switch pipe M1.Between the switch power supply system starting period, building-out capacitor C_COMPTo be charged. After the initial switch cycleIn the follow-up work cycle, inner sawtooth signal and the building-out capacitor voltage generating of Drive and Control Circuit 220V_COMPMake comparisons, when sawtooth signal reaches bucking voltage V_COMPTime, Drive and Control Circuit 220 is exportedBe used to indicate the cut-off signals of on-off switching tube M1. Equally, in the time that switching tube M1 turn-offs, feedback signalFB reduces gradually, and when feedback signal FB is during lower than threshold value, Drive and Control Circuit 220 outputs are used to indicate to be ledThe Continuity signal of logical switching tube M1. In this way, switch power supply system starts and enters normal work, opensClose periodically turn-on and turn-off of pipe M1, convert appropriate input voltage vin to required output current/ voltage Vout.

Fig. 3 A is according to the circuit diagram of the Drive and Control Circuit of an embodiment of the utility model. Fig. 3 AOnly show some assemblies relevant to the set of adaptive equalization electric capacity in the Drive and Control Circuit 220 of Fig. 2.Drive and Control Circuit 220 comprises the first comparator 301, the second comparator 302, ON time control module310 (they can comprise the 3rd comparator 303 and saw-toothed wave generator 312), the 4th comparator 304, firstSwitch S 1, second switch S2, the 3rd switch S 3, rest-set flip-flop 305, driver module 306, sampling are protectedHold module 307, current source 308, triode Q1.

According to an embodiment of the present utility model, in one or more initially the opening of switch power supply system startupIn the cycle of pass, sampling keeps module 307 to generate in one or more initial switch cycle of switching tube M1And the reference signal Vref1 that is inversely proportional to of the input voltage vin of maintenance and circuit for power conversion 210. For example,In one or more initial switch cycle, switch S 3 can be initial switch cycle control signal CTRL'sUnder control, keep module 307 to be connected to input voltage vin sampling. For example, referring to Fig. 2, in initial switchIn cycle, input voltage vin is charged to capacitor C1, thereby capacitor C1 will keep input electricityPress the peak voltage signal Vinpk of Vin. Correspondingly, sampling keeps module 307 can generate and maintenance and defeatedEnter the reference signal Vref1 that voltage Vin is inversely proportional to. Initial switch cycle control signal CTRL can be by meterNumber devices are realized the initial switch cycle count of setting, for example set one or more (for example, 3Individual, 5 etc.) export the first level in the switching tube M1 initial switch cycle, and after arriving count valueOutput second electrical level, thereby switch S 3 will be sampled in the initial switch cycle of setting, maintenance module 307 connectsBe connected to input voltage vin to generate the reference signal Vref1 being inversely proportional to Vin, and switch S 3 is being setAfter the initial switch end cycle of number, disconnect, thereby sampling keeps module 307 to keep and exports reference signalVref1. Sampling keeps module 307 also can generate by other means and maintenance and input voltage vin are inversely proportional toReference signal Vref1.

The first comparator 301 can receive by sampling keep the reference signal Vref1 that generates of module 307 and withThe detection signal Vdet that the bucking voltage Vcomp at building-out capacitor two ends is directly proportional (in one embodiment,Detection signal Vdet can be Vcomp itself). In the time that detection signal Vdet is less than reference signal Vref1,The first comparator 301 is exported asserts signal with to building-out capacitor C_COMPCharge, and at detection signalWhen Vdet is more than or equal to reference signal Vref1, the first comparator 301 outputs are removed asserts signal to stopTo building-out capacitor C_COMPCharge.

In addition, in the one or more initial switch cycle starting at switch power supply system, the initial switch cycleControl signal CTRL makes switch S 2 be closed into B, and the second comparator 302 works, ON time controlModule 310 conductively-closeds. Two inputs of the second comparator 302 receive respectively sampled voltage Vcs and defaultPeak value (for example, pre-set peak value current threshold). Using fixing ON time T_ONThe Switching Power Supply of controllingIn circuit, pre-set peak value can be a fixed inductance current peak K*V of initial setting_CSCC, can be by thisIndividual inductive current peak is determined the ON time T that needs set_ONCorresponding V_COMP. As switching tube M1When conducting, sampled signal CS increases gradually, when sampled signal CS increases to predetermined threshold K*V_CSCCTime,The output switching activity of the second comparator 302, is used to indicate driver module 306 outputs through rest-set flip-flop 305The cut-off signals of on-off switching tube M1. In the time that switching tube M1 turn-offs, feedback signal FB reduces gradually,When feedback signal FB is for example, during lower than threshold value Vref2 (, 0 value), the 4th comparator 304 overturns, warpRest-set flip-flop 305 makes driver module 306 outputs be used to indicate the Continuity signal of actuating switch pipe M1. ,In the one or more initial switch cycle starting at switch power supply system, can turn-off merit with peak point currentRate switching tube M1, sampling simultaneously keeps module 307 in the initial switch cycle, to detect input voltage vinPeak voltage signal Vinpk, the reference signal Vref1 that generation maintenance and input voltage vin are inversely proportional to.

In the follow-up work cycle after one or more initial switch end cycles, switch S 2 is closed intoA, the second comparator 302 conductively-closeds, ON time control module 310 works, thereby uses by V_COMPThe ON time T determining_ONControl switch-off power switch M1. As shown in the figure, ON time control module310 can comprise saw-toothed wave generator 312, and its generation has the sawtooth waveforms of predetermined period. ON time controlModule 310 also can comprise the 3rd comparator 303, and it receives the bucking voltage V at building-out capacitor two ends_COMPWithAnd the sawtooth waveforms that generates of saw-toothed wave generator 312, and be more than or equal to bucking voltage V at sawtooth waveforms_COMPTimeOutput cut-off signals, makes driver module 306 outputs be used to indicate on-off switching tube through rest-set flip-flop 305The shutoff of M1 drives signal. In the time that switching tube M1 turn-offs, feedback signal FB reduces gradually, works as feedback letterNumber FB is for example, during lower than threshold value Vref2 (, 0 value), and the 4th comparator 304 overturns, through rest-set flip-flop305 conductings that make driver module 306 outputs be used to indicate actuating switch pipe M1 drive signal. In follow-up workDo in the cycle, the first comparator 301 continues detection signal Vdet and reference signal Vref1 to compare,And in the time that detection signal Vdet is less than reference signal Vref1, output asserts signal disconnects switch S 1, electricityStream source 308 is held capacitor C by triode Q1 to COMP_COMPThe set of charging, and at detection signalWhen Vdet is more than or equal to reference signal Vref1, output is removed asserts signal and is made switch S 1 closure, current source308 ground connection, finish COMP end capacitor C_COMPCharge.

V in the time that system just starts_COMPBe 0 or very little, therefore Vdet is always less than Vref1, Q1 mono-Directly to building-out capacitor C_COMPThe set of charging, V_COMPRise gradually, ON time control module 310In sawtooth signal rise just can export more for a long time cut-off signals, thereby the ON time T of switching tube M1_ONAlso become gradually large. In the time of Vdet >=Vref1, asserts signal is removed in the first comparator 301 outputs makes switch S 1Closure, thus triode Q1 is turn-offed, finish COMP end capacitor C_COMPCharging set. ?After the set of COMP end finishes, C_COMPDo not recharge V_COMPKeep constant, thus T_ONAlso keep permanentDetermine, realized the constant on-time T of high PFC constant-current drive circuit_ON。

Because reference signal Vref1 and input voltage vin (or input voltage peak value Vinpk) are inversely proportional to,Determine thus COMP end set voltage V_COMPAlso by input voltage vin (or input voltage peak valueVinpk) be inversely proportional to, different COMP set voltage corresponding to input voltage vin, thus can be rightShould different ON time T_ON. For example, input voltage vin is higher, and set-point is lower, thereby can be certainlyThe different input voltage vin of moving adaptation.

Fig. 3 B is according to the circuit diagram of the Drive and Control Circuit of another embodiment of the utility model. Figure3B can comprise some assemblies similar to Fig. 3 A described above. Drive and Control Circuit 220 comprises the first ratioCompared with device 301, the second comparator 302, ON time control module 310 (its can comprise the 3rd comparator 303,Current source Is and capacitor C 0), the 4th comparator 304, the first switch S 1, second switch S2, the 3rd openClose S3, the 4th switch S 4, rest-set flip-flop 305, driver module 306, sampling maintenance module 307, electricityStream source 308, triode Q1 and ON time detection module 309.

Be similar to about Fig. 3 A described, switch power supply system start one or more initial switchIn cycle, initial switch cycle control signal CTRL makes switch S 2 be closed into B, the second comparator 302Work, 310 conductively-closeds of ON time control module. Two inputs of the second comparator 302 connect respectivelyReceive sampled voltage Vcs and pre-set peak value (for example, pre-set peak value current threshold). When switching tube M1 conductingTime sampled signal CS increase gradually, when sampled signal CS increases to predetermined threshold K*V_CSCCTime, secondThe output switching activity of comparator 302, makes driver module 306 outputs be used to indicate shutoff through rest-set flip-flop 305The cut-off signals of switching tube M1. In the time that switching tube M1 turn-offs, feedback signal FB reduces gradually, when insteadFeedback signal FB is for example, during lower than threshold value Vref2 (, 0 value), and the 4th comparator 304 overturns, and touches through RSHair device 305 makes driver module 306 outputs be used to indicate the Continuity signal of actuating switch pipe M1. , openingClose in one or more initial switch cycles that power-supply system starts, carry out switch-off power switch with peak point currentPipe M1.

Meanwhile, in the one or more initial switch cycle starting at switch power supply system, switch S 3 can beUnder the control of initial switch cycle control signal CTRL, keep module 307 to be connected to rest-set flip-flop sampling305 to sample and to keep time span that rest-set flip-flop 305 exports Continuity signal as with reference to signalVref1, thus sampling keeps module 307 can detect in the initial switch cycle by the fixed inductance of settingThe initial turn-on time (time of switching tube M1 in conducting state) that current peak produces also keeps thisIndividual ON time, supposes that this initial turn-on time is T_ON(FST). In addition, switch S 4 can be by CTRL'sInverse signalControl, in the initial switch cycle, ON time detection module 309 is disconnected thus, leadThe detection signal Vdet that logical time detecting module 309 is exported is 0 value or other invalid signals, and first relativelyDevice 301 is made comparisons detection signal Vdet and reference signal Vref1, and because detection signal Vdet is by littleExport asserts signal in reference signal Vref1 switch S 1 is disconnected, current source 308 is by triode Q1To COMP end capacitor C_COMPThe set of charging.

As above, for example, in the initial switch cycle starting in system (, in first initial switch cycle),Input capacitance C1 (referring to Fig. 2) is transfused to the crest voltage that voltage Vin charges and keeps input voltage vinSignal Vinpk, therefore initial turn-on time T_ON(FST)For:

$T_{ON\left(FST\right)}=\frac{K\×V_{CSCC}}{R_S}\×\frac{L}{Vinpk}---\left(2\right)$

Wherein K*V_CSCCDefault inductive current peak, R_SBe sampling resistor, L is circuit for power conversionFor example, energy storage inductor in 210 (, transformer), Vinpk is the peak voltage signal of input voltage vin.

In the follow-up work cycle after one or more initial switch end cycles, switch S 2 is closed intoA, the second comparator 302 conductively-closeds, ON time control module 310 works, thereby uses by V_COMPThe ON time T determining_ONControl switch-off power switch M1. As shown in the figure, when switching tube M1 conductingTime, the current source Is in ON time control module 310 charges to capacitor C 0, when 0 liang of capacitor CThe charging voltage V0 of end is higher than V_COMPTime, the output switching activity of the 3rd comparator 303, through rest-set flip-flop305 make driver module 306 outputs be used to indicate the cut-off signals of on-off switching tube M1. As switching tube M1When shutoff, for example, drive the inverse signal of signal DRGauge tap S5 closure, capacitor C 0 ground connection is also putElectricity zero clearing. In the time that switching tube M1 turn-offs, feedback signal FB reduces gradually, as feedback signal FB simultaneouslyFor example, during lower than threshold value Vref2 (, 0 value), the 4th comparator 304 overturns, and makes through rest-set flip-flop 305Driver module 306 outputs are used to indicate the Continuity signal of actuating switch pipe M1.

In the follow-up work cycle,Control ON time detection module 309 is connected to RS triggeringDevice 305 is exported the time span T of Continuity signal to detect rest-set flip-flop 305_ONAs detection signal Vdet., the ON time T of switching tube M1_ON(for example, detection signal Vdet) is input to the first comparator301. The first comparator 301 is by detection signal Vdet (its reflection ON time T_ON) and reference signal Vref1(its reflection initial turn-on time is T_ON(FST)) make comparisons, and at T_ONBe less than T_ON(FST)Time export setSignal disconnects switch S 1, and current source 308 is held capacitor C by triode Q1 to COMP_COMPCarry outCharging set, and at T_ONBe more than or equal to T_ON(FST)Time output is removed asserts signal and is made switch S 1 closure,Current source 308 ground connection, finish COMP end capacitor C_COMPCharge.

V in the time that system just starts_COMPBe 0 or very little, therefore T_ONAlways be less than T_ON(FST), Q1Directly to building-out capacitor C_COMPThe set of charging, V_COMPRise gradually, ON time control module 310In charge and discharge capacitance C0 need to charge and just can export more for a long time cut-off signals, thereby the conducting of switching tube M1Time T_ONAlso become gradually large. Work as T_ON≥T_ON(FST)Time, asserts signal is removed in the first comparator 301 outputsMake switch S 1 closure, thereby triode Q1 is turn-offed, finish COMP end capacitor C_COMPChargingSet. After the set of COMP end finishes, C_COMPDo not recharge V_COMPKeep constant, thus T_ONAlso keep constant, realized the constant on-time T of high PFC constant-current drive circuit_ON。

Therefore, V_COMPValue is provided by formula (3)

$V_{COMP}=\frac{K\×V_{CSCC}}{K1\×R_S}\×\frac{L}{Vinpk}---\left(3\right)$

Can find out COMP end set voltage V from formula (3)_COMPWith input voltage vin (or input electricityVoltage crest value Vinpk) be inversely proportional to, different COMP set voltage corresponding to input voltage vin, fromAnd ON time T that can be corresponding different_ON. For example, input voltage vin is higher, and set-point is lower, therebyCan automatically adapt to different input voltage vin.

Can find out COMP end set voltage V simultaneously from formula (3)_COMPWith circuit for power conversion 210The inductance value L of (for example, transformer) be directly proportional and with sampling resistor R_SBe inversely proportional to, therefore for notSame switch power supply system, due to L and R_SDifference, COMP end set voltage V_COMPCan be to some extent not yetWith, therefore can automatically adapt to the required T of different switch power supply systems_ON。

Fig. 4 be according to an embodiment of the utility model can the set of application self-adapting building-out capacitor anti-The circuit diagram of excitation type switch power-supply. Above-mentioned circuit for power conversion 210 can be transformer T1,Its former limit winding can be above-mentioned inductance L, and it receives input voltage Vac via rectifier bridge BD1, will inputVoltage Vac converts output voltage on secondary winding to and via diode D3 and RC filter circuit R5With C4, load (for example, LED lamp) is powered. Exchanging input Vac also charges to input capacitor C1.This system provides enabling signal Vcc between resistance R 1 and capacitor C2, and enabling signal Vcc can be toDrive and Control Circuit 220 is powered. For example, in the time that system starts, capacitor C2 charges until enabling signalVCC makes Drive and Control Circuit 220 enter normal work to control via DR terminal higher than after a certain threshold valueThe turn-on and turn-off of switching tube M1 processed. In addition, this system provides sampling electricity in one end of sampling resistor RsPress signal CS, on the auxiliary winding of transformer T1, work in coordination with resistance R 1 and capacitor by diode D1C2 powers to the power end Vcc of Drive and Control Circuit 220 together, and between feedback resistance R2 and R3Feedback voltage signal FB is provided. What start at switch power supply system as mentioned above, one or morely initially openingIn the cycle of pass, carry out switch-off power switching tube M1 with peak point current, in the time of switching tube M1 conducting, sampleSignal CS increases gradually, and in the time that sampled signal CS increases to predetermined threshold, Drive and Control Circuit 220 is defeatedGo out to be used to indicate the cut-off signals of on-off switching tube M1. The follow-up work cycle after the initial switch cycleIn, ON time control module 310 works, thereby by V_COMPThe ON time T determining_ONControlSwitch-off power switch M1. In the time that switching tube M1 turn-offs, feedback signal FB reduces gradually, works as feedback signalFB for example, during lower than threshold value (, when zero passage), and Drive and Control Circuit 220 outputs are used to indicate actuating switchThe Continuity signal of pipe M1.

In one embodiment, in one or more initial switch cycle of switching tube M1, sampling keepsThe reference signal Vref1 that module 307 generates and maintenance and input voltage vin are inversely proportional to. The first comparator 301The detection signal Vdet that receives Vref1 and be directly proportional to bucking voltage Vcomp, and at detection signal VdetWhile being less than reference signal Vref1, export asserts signal with to building-out capacitor C_COMPCharge, and detectingWhen signal Vdet is more than or equal to reference signal Vref1, output is removed asserts signal to stop building-out capacitorC_COMPCharge.

In another embodiment, in one or more initial switch cycle of switching tube M1, sampling is protectedHold module 307 and detect initial turn-on time T_ON(FST)And generating reference signal Vref1 correspondingly. Initially openingIn the follow-up work cycle after the cycle of pass, the conducting of ON time detection module 309 sense switch pipe M1Time T_ONAs detection signal Vdet. By detection signal Vdet, (it reflects conducting to the first comparator 301Time T_ON) (its reflection initial turn-on time is T with reference signal Vref1_ON(FST)) make comparisons, andT_ONBe less than T_ON(FST)In time, exports asserts signal switch S 1 is disconnected, and current source 308 is by triode Q1To COMP end capacitor C_COMPThe set of charging, and at T_ONBe more than or equal to T_ON(FST)Time output is separatedExcept asserts signal makes switch S 1 closure, current source 308 ground connection, finish COMP end capacitor C_COMPEnterRow charging. V in the time just starting_COMPBe 0 or very little, therefore T_ONAlways be less than T_ON(FST)Thereby,Always to building-out capacitor C_COMPThe set of charging, V_COMPRise gradually, thereby make ON time T_ONAlso become gradually large. Work as T_ON≥T_ON(FST)Time, finish COMP end capacitor C_COMPSet, C_COMPDo not recharge V_COMPKeep constant, thus T_ONAlso keep constant, realized constant on-time T_ON。

Fig. 5 be according to an embodiment of the utility model can the set of application self-adapting building-out capacitor literThe circuit diagram of step down switching regulator. The former limit winding of transformer T1 can be above-mentioned inductance L, itsVia rectifier bridge BD1 reception input voltage Vac and via diode D2 and RC filter circuit R5 and C4Load (for example, LED lamp) is powered. Exchanging input Vac also charges to input capacitor C1. This isSystem provides enabling signal Vcc between resistance R 1 and capacitor C2, and enabling signal Vcc can be to drivingControl circuit 220 is powered. In addition, this system provides sampled voltage signal CS in one end of sampling resistor Rs,On the secondary winding of transformer T1 by the collaborative resistance R 1 of diode D1 together with capacitor C2 to drivingThe power end Vcc power supply of moving control circuit 220, and feedback electricity is provided between feedback resistance R2 and R3Press signal FB. As mentioned above, in the one or more initial switch cycle starting at switch power supply system,Carry out switch-off power switching tube M1 with peak point current, in the time of switching tube M1 conducting, sampled signal CS is graduallyIncrease, in the time that sampled signal CS increases to predetermined threshold, Drive and Control Circuit 220 outputs are used to indicate passThe cut-off signals of disconnected switching tube M1. In the follow-up work cycle after the initial switch cycle, ON timeControl module 310 works, thereby by V_COMPThe ON time T determining_ONControl switch-off power switchM1. In the time that switching tube M1 turn-offs, feedback signal FB reduces gradually, when feedback signal FB is lower than threshold valueTime (for example, when zero passage), Drive and Control Circuit 220 output is used to indicate the conducting of actuating switch pipe M1Signal.

In one embodiment, in one or more initial switch cycle of switching tube M1, sampling keepsThe reference signal Vref1 that module 307 generates and maintenance and input voltage vin are inversely proportional to. The first comparator 301The detection signal Vdet that receives Vref1 and be directly proportional to bucking voltage Vcomp, and at detection signal VdetWhile being less than reference signal Vref1, export asserts signal with to building-out capacitor C_COMPCharge, and detectingWhen signal Vdet is more than or equal to reference signal Vref1, output is removed asserts signal to stop building-out capacitorC_COMPCharge.

In another embodiment, in one or more initial switch cycle of switching tube M1, sampling is protectedHold module 307 and detect initial turn-on time T_ON(FST)And generating reference signal Vref1 correspondingly. Initially openingIn the follow-up work cycle after the cycle of pass, the conducting of ON time detection module 309 sense switch pipe M1Time T_ONAs detection signal Vdet. By detection signal Vdet, (it reflects conducting to the first comparator 301Time T_ON) (its reflection initial turn-on time is T with reference signal Vref1_ON(FST)) make comparisons, andT_ONBe less than T_ON(FST)In time, exports asserts signal switch S 1 is disconnected, and current source 308 is by triode Q1To COMP end capacitor C_COMPThe set of charging, and at T_ONBe more than or equal to T_ON(FST)Time output is separatedExcept asserts signal makes switch S 1 closure, current source 308 ground connection, finish COMP end capacitor C_COMPEnterRow charging. V in the time just starting_COMPBe 0 or very little, therefore T_ONAlways be less than T_ON(FST)Thereby,Always to building-out capacitor C_COMPThe set of charging, V_COMPRise gradually, make ON time T_ONAlsoBecome gradually large. Work as T_ON≥T_ON(FST)Time, finish COMP end capacitor C_COMPSet, C_COMPNoRecharge V_COMPKeep constant, thus T_ONAlso keep constant, realized constant on-time T_ON。

Fig. 6 be according to an embodiment of the utility model can the set of application self-adapting building-out capacitor fallThe circuit diagram of pusher-type switch power supply. The former limit winding L 1a of transformer can be above-mentioned inductance L, its warpReceive input voltage Vac via RC filter circuit R7 and C4 to load (for example, by rectifier bridge BD1LED lamp) power supply. Exchanging input Vac also charges to input capacitor C1. This system resistance R 1,Between R2 and capacitor C3, provide enabling signal Vcc, enabling signal Vcc can be to Drive and Control Circuit220 power supplies. In addition, this system provides sampled voltage signal CS in one end of sampling resistor Rs, in transformationDevice secondary winding L 1b upper by the collaborative resistance R 1 of diode D1, R2 together with capacitor C3 to drivingThe power end Vcc power supply of control circuit 220, and provide feedback voltage between feedback resistance R5 and R6Signal FB. As mentioned above, in the one or more initial switch cycle starting at switch power supply system, makeCarry out switch-off power switching tube M1 with peak point current, in the follow-up work cycle after the initial switch cycle,By V_COMPThe ON time T determining_ONControl switch-off power switch M1.

In one embodiment, in one or more initial switch cycle of switching tube M1, sampling keepsThe reference signal Vref1 that module 307 generates and maintenance and input voltage vin are inversely proportional to. The first comparator 301The detection signal Vdet that receives Vref1 and be directly proportional to bucking voltage Vcomp, and at detection signal VdetWhile being less than reference signal Vref1, export asserts signal with to building-out capacitor C_COMPCharge, and detectingWhen signal Vdet is more than or equal to reference signal Vref1, output is removed asserts signal to stop building-out capacitorC_COMPCharge.

In another embodiment, in one or more initial switch cycle of switching tube M1, sampling is protectedHold module 307 and detect initial turn-on time T_ON(FST)And generating reference signal Vref1 correspondingly. Initially openingIn the follow-up work cycle after the cycle of pass, the conducting of ON time detection module 309 sense switch pipe M1Time T_ONAs detection signal Vdet. By detection signal Vdet, (it reflects conducting to the first comparator 301Time T_ON) (its reflection initial turn-on time is T with reference signal Vref1_ON(FST)) make comparisons, andT_ONBe less than T_ON(FST)In time, exports asserts signal switch S 1 is disconnected, and current source 308 is by triode Q1To COMP end capacitor C_COMPThe set of charging, and at T_ONBe more than or equal to T_ON(FST)Time output is separatedExcept asserts signal makes switch S 1 closure, current source 308 ground connection, finish COMP end capacitor C_COMPEnterRow charging. Along with to building-out capacitor C_COMPThe set of charging, V_COMPRise gradually, ON time T_ONAlso become gradually large, work as T_ON≥T_ON(FST)Time, finish COMP end capacitor C_COMPSet, V_COMPKeep constant, thus T_ONAlso keep constant, realized constant on-time T_ON。

The utility model discloses Drive and Control Circuit and drive control method and Switching Power Supply, and referenceAccompanying drawing has been described detailed description of the invention of the present utility model and effect. It should be understood that above-described embodiment onlyTo exemplary illustration of the present utility model, instead of to restriction of the present utility model, any this reality that do not exceedCreate by utility model within the scope of novel connotation, comprise various Switching Power Supply drive systems application,Under the spirit of the change of the local structure to circuit, the adaptive equalization electric capacity set providing at the utility modelTo the change of circuit implementing method, the type to components and parts or the replacement of model, other of various signal levelsReplacement or the amendment etc. of modification and other unsubstantialities, within all falling into the utility model protection domain.

Claims (15)

1. a Drive and Control Circuit, described Drive and Control Circuit is used for control and compensation electric capacity and switching tube,Described Drive and Control Circuit comprises:

Sampling keeps module, and it generates and keep in one or more initial switch cycle of described switching tubeThe reference signal being inversely proportional to the input voltage of circuit for power conversion; And

The first comparator, it receives by the described reference signal of described sampling maintenance module generation and with describedThe detection signal that the bucking voltage at building-out capacitor two ends is directly proportional, is less than described with reference to letter at described detection signalNumber time export asserts signal so that described building-out capacitor is charged, and be more than or equal at described detection signalWhen described reference signal, output is removed asserts signal and described building-out capacitor is charged stopping.

2. Drive and Control Circuit as claimed in claim 1, is characterized in that, described driving control electricityRoad also comprises:

The first current source, it is connected to described building-out capacitor; And

The first switch, it is connected between described current source and ground connection, and described the first switch is at described the first ratioDuring compared with device output asserts signal, disconnect so that described the first current source charges to described building-out capacitor, and described inThe first switch closed so that described first current source in the time that asserts signal is removed in described the first comparator output stopsOnly to described building-out capacitor charging.

3. Drive and Control Circuit as claimed in claim 2, is characterized in that, described driving control electricityRoad also comprises:

Be connected to the triode between described the first current source and described building-out capacitor.

4. Drive and Control Circuit as claimed in claim 1, is characterized in that, described driving control electricityRoad also comprises:

The second comparator, it receives described power in one or more initial switch cycle of described switching tubeThe sampled voltage of change-over circuit and pre-set peak value, and be more than or equal to described pre-set peak value at described sampled voltageTime export the first cut-off signals to turn-off described switching tube; And

ON time control module, its follow-up work week after described one or more initial switch cyclesBucking voltage and the sawtooth signal at the described building-out capacitor of interim reception two ends, and in described sawtooth signalWhile being more than or equal to described bucking voltage, export the second cut-off signals to turn-off described switching tube.

5. Drive and Control Circuit as claimed in claim 4, is characterized in that, described ON time controlMolding piece comprises:

Saw-toothed wave generator, its generation has the sawtooth waveforms of predetermined period;

The 3rd comparator, it receives bucking voltage and the described sawtooth waveforms at described building-out capacitor two ends, andWhen being more than or equal to described bucking voltage, exports described sawtooth waveforms described the second cut-off signals.

6. Drive and Control Circuit as claimed in claim 4, is characterized in that, described ON time controlMolding piece comprises:

The second current source; And

Be connected to the charge and discharge capacitance of described the second current source, described charge and discharge capacitance is in described switching tube conductingIn time, is charged by described the second current source, and electric discharge in the time that described switching tube turn-offs, and wherein said sawtooth waveforms is instituteState the voltage at charge and discharge capacitance two ends.

7. the Drive and Control Circuit as described in any one in claim 1 to 6, is characterized in that, instituteStating Drive and Control Circuit also comprises:

Driver module, its output drive signal is with conducting or turn-off described switching tube; And

Second switch, it compares described second in one or more initial switch cycle of described switching tubeThe output of device is connected to described driver module, and follow-up after described one or more initial switch cyclesIn work period, the output of described ON time control module is connected to described driver module.

8. Drive and Control Circuit as claimed in claim 7, is characterized in that, described driving control electricityRoad also comprises:

Rest-set flip-flop, it is connected between described second switch and described driver module, and described RS triggersDevice is exported by described the second comparator or described ON time control module via described second switch receptionThe first or second cut-off signals also provides cut-off signals to turn-off described switching tube to described driver module.

9. Drive and Control Circuit as claimed in claim 8, is characterized in that, described driving control electricityRoad also comprises:

The 4th comparator, it receives the feedback voltage signal of described circuit for power conversion, and at described feedback electricityWhile pressing signal lower than predetermined threshold value voltage, export Continuity signal, described rest-set flip-flop receives described Continuity signalAnd described Continuity signal is offered to described driver module with switching tube described in conducting.

10. Drive and Control Circuit as claimed in claim 9, is characterized in that, described sampling keeps mouldPiece in described one or more initial switch cycles, be connected to described rest-set flip-flop with sample and keep described inThe time span of rest-set flip-flop output Continuity signal is as described reference signal.

11. Drive and Control Circuit as claimed in claim 9, is characterized in that, described driving control electricityRoad also comprises:

ON time detection module, its follow-up work week after described one or more initial switch cyclesInterimly be connected to described rest-set flip-flop and do with the time span that detects described rest-set flip-flop output Continuity signalFor described detection signal.

12. 1 kinds of Switching Power Supplies, comprising:

Drive and Control Circuit as described in any one in claim 1-11;

Described circuit for power conversion, for converting input voltage to output voltage;

Be connected to the described switching tube of described circuit for power conversion; And

Be connected to the described building-out capacitor of described Drive and Control Circuit.

13. Switching Power Supplies as claimed in claim 12, is characterized in that, described Switching Power Supply also comprisesBe connected to the feedback resistive network of output of described circuit for power conversion so that described circuit for power conversion to be providedFeedback voltage signal.

14. Switching Power Supplies as claimed in claim 12, is characterized in that, described Switching Power Supply also comprisesThe sampling resistor of connecting with described switching tube is to provide the sampled voltage of described circuit for power conversion.

15. Switching Power Supplies as claimed in claim 12, is characterized in that, described Switching Power Supply comprises insteadAt least one in excitation type switch power-supply, step-down/up type Switching Power Supply or step down switching regulator.