CN102377357A - Synchronous rectification controller, power switching circuit and synchronous rectification control method - Google Patents
Synchronous rectification controller, power switching circuit and synchronous rectification control method Download PDFInfo
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- CN102377357A CN102377357A CN2010102512576A CN201010251257A CN102377357A CN 102377357 A CN102377357 A CN 102377357A CN 2010102512576 A CN2010102512576 A CN 2010102512576A CN 201010251257 A CN201010251257 A CN 201010251257A CN 102377357 A CN102377357 A CN 102377357A
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Abstract
The invention relates to a prediction type secondary side synchronous rectification controller, which is used for controlling at least one synchronous rectification switch. The synchronous rectification controller is provided with a sawtooth wave generator, a peak sampling unit and an output control unit, wherein the sawtooth wave generator receives a synchronous signal so as to generate a sawtooth wave signal; the peak sampling unit captures peak voltage of the sawtooth wave signal so as to generate a prediction reference voltage signal; and the sawtooth wave signal is compared with the prediction reference voltage signal by the output control unit so as to generate a synchronous rectification control signal to control the conduction state of the switch.
Description
Technical field
The present invention relates to an a kind of synchronous commutation controller and control method thereof that is applied to exchange type power conversion circuit, especially a kind of prediction type secondary side synchronous rectifier controller and control method thereof.
Background technology
In the technical field of power source conversion, utilize transistor switch to replace diode to reduce power consumption, be a common technological means.
Fig. 1 is the power-switching circuit that a typical case has the secondary side synchronous rectifier function.The primary side of power-switching circuit has a PDM keyer 11 and a main switch 12.PDM keyer 11 is according to the feedback signal from isolated feedback device 13, and output pulse signal is controlled the conducting of main switch 12 or ended.The primary side of power-switching circuit has a synchronous rectifier switch 15 and a primary side synchronous rectifying controller 20.Secondary side synchronous rectifier controller 20 is according to the signal from the primary side winding 142 of transformer 14, the conducting of control synchronous rectification switch 15 or end.
When main switch 12 conductings, direct-flow input end VIN provides electrical power to the primary side winding 141 of transformer 14.At the same time, 15 of synchronous rectification switchs are to appear to end.Therefore, the electric power from direct-flow input end VIN can be stored in the transformer 14.Subsequently, when main switch 12 transfer to by the time, secondary side synchronous rectifier controller 20 detects the variation of the polarity of voltage of primary side winding 142, control synchronous rectification switch 15 conductings.At this moment, transformer 14 beginning release stored energy are to output VO and filter capacitor 16.
It should be noted that the work period of secondary side synchronous rectifier controller 20 necessary accurately control synchronous rectification switchs 15,, avoid causing the conversion efficiency loss or cause switch to burn with the running of simulating diode.With regard to the power-switching circuit of Fig. 1, the main switch 12 of primary side must alternate conduction with the synchronous rectification switch 15 of primary side.Overlapping in order to prevent main switch 12 with the ON time of synchronous rectification switch 15, between the ON time of the ON time of main switch 12 and synchronous rectification switch 15, must reservation one Dead Time (dead time).That is in this Dead Time, main switch 12 all is to appear to end with synchronous rectification switch 15.
Secondary side synchronous rectifier controller 20 among Fig. 1 adopts complicated digital control approach to calculate Dead Time.Shown in figure, this primary side synchronous rectifying controller 20 has a clock pulse buffer cell (Clock Buffer) 22, one numeral by controller (Digital Turn-off Controller) 24 and one output driver element 26.
Fig. 2 is the block schematic diagram that the numeral among Fig. 1 is ended controller 24.Shown in figure, numeral comprises an oscillating unit 242, one first counter 243, one second counter 244, a finite state control device (Finite States Machine) 246 and one output control unit (Output Control) 248 by controller 24.Wherein, first counter 243 and second counter 244 are and can go up number and the counter of counting down.Oscillating unit 242 supplies the usefulness of first counter 243 and second counter, 244 countings in order to produce an inner counting clock signal CLK.Finite state control device 246 receives outer synchronous signal Sync, and controls during the counting of first counter 243 and second counter 244 according to this outside synchronizing signal Sync.The output signal of the primary side winding 142 of this outside synchronizing signal Sync transformer 14.
Fig. 3 is the oscillogram of numeral each control signal in controller 24.Please be simultaneously with reference to Fig. 2; When finite state control device 246 detects the leading edge of the first switch periods TS1 of outer synchronous signal Sync; Control first counter 243 and begin to go up number, detect the leading edge of the second switch cycle T S2 of outer synchronous signal Sync up to finite state control device 246.Subsequently, finite state control device 246 controls first counter 243 begins number down, detects the leading edge of the 3rd switch periods TS3 of outer synchronous signal Sync up to finite state control device 246.Suppose on first counter 243 is in the first switch periods TS1 and count to n; When first counter is counted to n-x 243 times; Finite state control device 246 produces an output pick-off signal immediately, and control output control unit 248 stops to export Continuity signal (being the drive signal OUT of high potential).The numerical value of x is the count number of preset Dead Time, and its big I is set end DTS through the dead band and set.
In addition; When finite state control device 246 detects the leading edge of second switch cycle T S2 of outer synchronous signal Sync; Together with the time control second counter 244 and begin to go up number, detect the leading edge of the 3rd switch periods TS3 of outer synchronous signal Sync up to finite state control device 246.The running of second counter 244 and first counter 243 is similar.In the 3rd switch periods TS3, finite state control device 246 promptly is the count number according to second counter 244, produces an output pick-off signal, and control output control unit 248 stops to export Continuity signal.
This primary side synchronous rectifying controller 20 utilizes going up number and counting course down of counter 243,244, can effectively predict the ON time of synchronous rectification switch in the next switch periods, keeps the Dead Time of almost fixed simultaneously.But, the circuit design of this primary side synchronous rectifying controller 20 is quite complicated, and cost of manufacture is difficult for reducing.
Summary of the invention
A main purpose of the present invention is that circuit structure is complicated problems too to traditional prediction type secondary side synchronous rectifier controller, proposes the method that solves.
Another main purpose of the present invention provides a kind of analogue type secondary side synchronous rectifier controller, and accurate control dead area time is to avoid power supply conversion efficiency to reduce or to cause switch to burn.
In order to reach aforementioned purpose, one embodiment of the invention provide a kind of prediction type secondary side synchronous rectifier controller, in order to control at least one switch.This synchronous rectifying controller has a sawtooth generator, a peak sample unit, an output control unit.Wherein, sawtooth generator receives a synchronous signal, to produce a sawtooth signal.One crest voltage of peak sample unit acquisition sawtooth signal produces a reference voltage signal according to this.Output control unit is sawtooth signal and reference voltage signal relatively; To produce a synchronous rectification control signal; The conducting state of control switch, when the current potential of this sawtooth signal was higher than the current potential of this prediction reference voltage signal, this output control unit turn-offed this synchronous rectification switch.
One embodiment of the invention and provide one have a prediction type synchronous rectification power-switching circuit.This power-switching circuit has a transformer, a synchronous rectifier switch and a prediction type secondary side synchronous rectifier controller.Wherein, transformer comprises a primary side winding and a primary side winding.Synchronous rectification switch is connected to the primary side winding.Prediction type secondary side synchronous rectifier controller is in order to the control synchronous rectification switch.This primary side synchronous rectifying controller has a sawtooth generator, a peak sample unit and an output control unit.Wherein, sawtooth generator receives a synchronous signal, to produce a sawtooth signal.One crest voltage of peak sample unit acquisition sawtooth signal produces a reference voltage signal according to this.Output control unit is sawtooth signal and reference voltage signal relatively; To produce a synchronous rectification control signal; The conducting state of control synchronous rectification switch, when the current potential of this sawtooth signal was higher than the current potential of this prediction reference voltage signal, this output control unit turn-offed this synchronous rectification switch.
One embodiment of the invention also provide a kind of prediction type synchronous rectification control method, to control a synchronous rectifier switch of a power-switching circuit.This prediction type synchronous rectification control method comprises the following steps: that at least (a) according to a synchronous signal, produces identical sawtooth signal of one-period; (b) according to the crest voltage of sawtooth signal, in the following one-period of sawtooth signal, generation one is the reference voltage signal of decay progressively, and a maximum voltage of this reference voltage signal is less than this crest voltage of sawtooth signal; And (c) comparison reference voltage signal and the sawtooth signal of following one-period, to produce a synchronous rectification control signal, the conducting state of control synchronous rectification switch.
Can further be understood by means of following detailed Description Of The Invention and accompanying drawing about advantage of the present invention and spirit.
Description of drawings
Fig. 1 is the power-switching circuit that a typical case has the secondary side synchronous rectifier function;
Fig. 2 is the block schematic diagram that the numeral among Fig. 1 is ended controller;
Fig. 3 is the oscillogram of numeral by the control signal of controller;
Fig. 4 is the circuit diagram of synchronous rectified power change-over circuit one first embodiment of the present invention;
Fig. 5 is the circuit diagram of synchronous rectified power change-over circuit one second embodiment of the present invention;
Fig. 6 is the circuit diagram of secondary side synchronous rectifier controller one first embodiment of Fig. 4;
Fig. 7 is the control waveform figure of the secondary side synchronous rectifier controller of Fig. 6;
Fig. 8 is the circuit diagram of secondary side synchronous rectifier controller one second embodiment of the present invention;
Fig. 9 is the oscillogram of control signal one preferred embodiment of the secondary side synchronous rectifier controller of Fig. 8;
Figure 10 is the circuit diagram of secondary side synchronous rectifier power-switching circuit 1 the 3rd embodiment of the present invention;
Figure 11 is the oscillogram of control signal one preferred embodiment of the secondary side synchronous rectifier controller of Figure 10.
[main element description of reference numerals]
Secondary side synchronous rectifier controller 20
Primary side winding 141
Primary side winding 142
Input VIN
Output VO
Clock pulse buffer cell 22
Numeral is by controller 24
Oscillating unit 242
Finite state control device 246
Counting clock signal CLK
Synchronizing signal Sync, Sync0, Sync1
The first switch periods TS1
Second switch cycle T S2
The 3rd switch periods TS3
End DTS is set in the dead band
Secondary side synchronous rectifier controller 40
Transformer 34
Primary side winding 341
Primary side winding 342
Primary side is assisted winding 344
Sawtooth generator 42
Sawtooth signal Ramp
Prediction reference voltage signal PS
Synchronous rectification control signal SRC
Drive signal OUT
Dead Time control signal Comp
Trailing edge trigger impulse FTP
Leading edge trigger impulse RTP
Sawtooth waveforms produces electric capacity 422
Keep electric capacity 442
Releasing member 444
Trailing edge trigger element 427
Primary side winding 541
Primary side winding 542
Secondary side synchronous rectifier controller 60
Reference bias Vr
Power input VCC
The first primary side turn-on cycle ta1
Second subprime side turn-on cycle ta2
Level side turn-on cycle ta3 for the third time
The first primary side turn-on cycle tb1
The second primary side turn-on cycle tb2
Dead Time td
Embodiment
The present invention is a kind of prediction type secondary side synchronous rectifier controller and method.This control circuit and control method can be applicable to flyback, forward type, semibridge system or full-bridge type topology in continuous current mode (Current Continuous Mode, control CCM).In addition, prediction type secondary side synchronous rectifier controller of the present invention adopts the turn-on cycle of easy analog circuit control synchronous rectification switch, is suitable for the secondary side synchronous rectifier control of various fixed switched power suppliers frequently.
Prediction type secondary side synchronous rectifier controller of the present invention; Produce a sawtooth signal according to a primary side synchronizing signal; And the crest voltage of acquisition sawtooth signal, produce corresponding reference voltage, and this reference voltage is compared with the sawtooth signal of next work period; To produce a dead band signal, cutoff synchronization rectifier switch.
Fig. 4 is the circuit diagram of synchronous rectified power change-over circuit one first embodiment of the present invention.Present embodiment one flyback power-switching circuit.Shown in figure, the primary side of this power-switching circuit has a PDM keyer 31 and a main switch 32.PDM keyer 31 is according to the feedback signal from isolated feedback device 33, and output pulse signal is controlled the conducting of main switch 32 or ended.The primary side of this power-switching circuit has a synchronous rectifier switch 35 and a primary side synchronous rectifying controller 40.These primary side synchronous rectifying controller 40 foundations one are corresponding to the synchronizing signal Sync0 of the pulse signal of primary side, the conducting state of control synchronous rectification switch 35.In the present embodiment, secondary side synchronous rectifier controller 40 is according to a synchronous signal Sync0 of the auxiliary winding 344 of the primary side that comes from transformer 34, controls the conducting of synchronous rectification switch 35 or ends.The height potential change of this synchronizing signal Sync0 is opposite with the pulse signal of primary side.
When 32 conductings of pulse signal control main switch, direct-flow input end VIN provides electrical power to the primary side winding 341 of transformer 34.At the same time, secondary side synchronous rectifier controller 40 control synchronous rectification switchs 35 end.Therefore, the electric power from direct-flow input end VIN can be stored in the transformer 34.Subsequently, when pulse signal control main switch 32 transfer to by the time, the current potential of synchronizing signal Sync0 changes.After the current potential that secondary side synchronous rectifier controller 40 detects synchronizing signal Sync0 changes, 35 conductings of control synchronous rectification switch.At this moment, transformer 34 beginning release stored energy are to output VO and filter capacitor 36.
Fig. 6 is the circuit diagram of secondary side synchronous rectifier controller 40 one the first embodiment of Fig. 4.Shown in figure, this primary side synchronous rectifying controller 40 has a sawtooth generator 42, a peak sample unit 44, an output control unit 46 and exports driver element 48 with one.Wherein, sawtooth generator 42 receives a synchronous signal Sync0, to produce a sawtooth signal Ramp.The crest voltage of peak sample unit 44 acquisition sawtooth signal Ramp produces a prediction reference voltage signal PS according to this.Output control unit 46 is sawtooth signal Ramp and prediction reference voltage signal PS relatively, to produce a synchronous rectification control signal SRC.Output driver element 48 produces a drive signal OUT according to this synchronous rectification control signal SRC, the conducting state of control synchronous rectification switch 35.
Secondly, the secondary side synchronous rectifier controller 40 of present embodiment has a power input VCC.External power source is supplied power to sawtooth generator 42 and output driver element 48 through this power input VCC.Please be simultaneously with reference to shown in Figure 4, in the present embodiment, this power input VCC is connected to the auxiliary winding 344 of a primary side.But, the present invention is not limited to this.This power input VCC also can be connected to other DC power supplys.
Fig. 7 is the control waveform figure of the secondary side synchronous rectifier controller of Fig. 6.Shown in figure, in the first primary side turn-on cycle ta1, synchronizing signal Sync0 is in high potential, and reset switch 426 is in cut-off state.At this moment, charge power supply 424 produces electric capacity 422 chargings to sawtooth waveforms, and the current potential that makes sawtooth waveforms produce the high-pressure side of electric capacity 422 progressively improves (that is current potential of sawtooth signal Ramp).Subsequently, when getting into the first primary side turn-on cycle tb1, synchronizing signal Sync0 changes electronegative potential into.At this moment, reset switch 426 conductings, sawtooth waveforms produces electric capacity 422 and discharges rapidly, to form sawtooth signal Ramp.Subsequently, when getting into second subprime side turn-on cycle ta2, synchronizing signal Sync0 overline changes high potential into, and reset switch 426 is ended once again, makes sawtooth waveforms produce electric capacity 422 and charges again.
The voltage of sawtooth signal Ramp can be stored to through reference bias source 446 and peak sample circuit 448 and keep electric capacity 442.The reference bias Vr that reference bias source 446 is provided can make and keep the crest voltage of the stored maximum voltage of electric capacity 442 less than sawtooth signal Ramp.When getting into the first primary side turn-on cycle tb1, the current potential of sawtooth signal Ramp can reduce fast.That compares is following and since keep electric charges in the electric capacity 442 be through one have high impedance releasing member 444 slowly discharges, therefore, the current potential of the prediction reference voltage signal PS that is exported by the high-pressure side of maintenance electric capacity 442 can progressively slowly reduce.
After getting into second subprime side turn-on cycle ta2, the current potential of sawtooth signal Ramp rises once again.But, the current potential of prediction reference voltage signal PS still slowly reduces.Originally, the current potential of sawtooth signal Ramp remains the current potential that is lower than prediction reference voltage signal PS.Along with the current potential of sawtooth signal Ramp progressively rises, at a specific time point, after the current potential of sawtooth signal Ramp rose to the current potential above prediction reference voltage signal PS, comparator 462 produced a dead band (dead time) control signal Comp immediately.Dead Time control signal Comp is in order to the time span of the second subprime side turn-on cycle ta2 of adjustment synchronizing signal Sync0, to produce synchronous rectification control signal SRC.
The Dead Time control signal Comp of this high potential can last till that the second primary side turn-on cycle tb2 begins.Shown in figure, the time point of the ascent stage of synchronous rectification control signal SRC is identical with synchronizing signal Sync0, and but, the time point of the descending branch of synchronous rectification control signal SRC then is to be determined by Dead Time control signal Comp.
Dead Time control signal Comp is at primary side turn-on cycle ta1, and ta2 defines Dead Time td in the ta3.Shown in figure, be the prediction reference voltage signal PS through second turn-on cycle relatively and determine corresponding to the sawtooth signal Ramp of second subprime side turn-on cycle ta2 corresponding to the Dead Time td of second turn-on cycle (comprising the second primary side turn-on cycle tb2 and second subprime side turn-on cycle ta2).The maximum voltage of the prediction reference voltage signal PS of second turn-on cycle then is to be determined by the crest voltage corresponding to the sawtooth signal Ramp of the first primary side turn-on cycle ta1.
In each turn-on cycle, the descending slope of the rate of rise of sawtooth signal Ramp and prediction reference voltage signal PS all is to keep necessarily.Therefore, the duration of the high potential synchronous rectification control signal SRC of each turn-on cycle is that crest voltage by the sawtooth signal Ramp of previous turn-on cycle determines that just the time span by previous primary side turn-on cycle determines.
The rate of rise of sawtooth signal Ramp can be adjusted through the capacitance that changes sawtooth waveforms generation electric capacity 422, and the descending slope of prediction reference voltage signal PS can be adjusted with keeping electric capacity 442 through releasing member 444.The length of Dead Time td can be adjusted through the rate of rise of change sawtooth signal Ramp and the descending slope of prediction reference voltage signal PS.The capacitance that sawtooth waveforms produces electric capacity 422 is big more, and the impedance of releasing member 444 is big more, keeps the capacitance of electric capacity 442 big more, and Dead Time td is short more.
Fig. 5 is the circuit diagram of synchronous rectification flyback power-switching circuit one second embodiment of the present invention.In the embodiment of Fig. 4, synchronous rectification switch 35 is arranged between primary side winding 342 and the earth terminal, and 35 of the synchronous rectification switchs of present embodiment are to be arranged between primary side winding 342 and the output VO.In addition; In the embodiment of Fig. 4; Secondary side synchronous rectifier controller 40 is to be connected to the required electric energy of auxiliary winding 344 acquisitions of primary side; 40 of the secondary side synchronous rectifier controllers of present embodiment are to be connected to primary side winding 342, and the auxiliary winding 344 of primary side also changes the output that is connected in series to primary side winding 342 into.Though it is different that circuit connects, but the operation principles of the secondary side synchronous rectifier controller 40 of present embodiment and the embodiment of Fig. 4 are roughly the same, do not give unnecessary details at this.
Fig. 8 is the circuit diagram of secondary side synchronous rectifier controller one second embodiment of the present invention.Fig. 9 is the oscillogram of corresponding control signal.Embodiment compared to Fig. 6; The sawtooth generator 42 of present embodiment has a trailing edge trigger element 427; The trailing edge (Falling Edge) of acquisition synchronizing signal Sync0 to produce 426 conductings of trailing edge trigger impulse FTP control reset switch, makes sawtooth waveforms produce electric capacity 422 discharges.In addition, the sawtooth generator 42 of Fig. 6 is to utilize synchronizing signal Sync0 control reset switch 426 to carry out periodic conducting, and produces the sawtooth signal Ramp of noncontinuity.In comparison, present embodiment utilizes trailing edge trigger impulse FTP conducting reset switch 426, significantly shortens the ON time of reset switch 426, and produces the sawtooth signal Ramp of approximate continuity.The operation principles of other parts of this primary side synchronous rectifying controller 40 and the embodiment of Fig. 6 are roughly the same, do not give unnecessary details at this.
Figure 10 is the circuit diagram of synchronous rectified power change-over circuit 1 the 3rd embodiment of the present invention.Present embodiment one forward type power-switching circuit.The difference of the flyback power-switching circuit of itself and first embodiment of the invention is; The polarity of the primary side winding 542 of present embodiment is different with the primary side winding 342 of first embodiment, the synchronous rectification switch 55 of present embodiment that the position is set is different with the synchronous rectification switch 35 of first embodiment.This synchronous rectification switch 55 constitutes a loop with primary side winding 542.And, between synchronous rectification switch 55 and filter capacitor 36, be connected with an inductance 56.In addition, present embodiment has omitted the auxiliary winding 344 of primary side among first embodiment.
Secondly, in the present embodiment, secondary side synchronous rectifier controller 60 is connected to the front end of primary side rectifier diode 57 with acquisition synchronizing signal Sync1.In the embodiment of Fig. 4 and Fig. 5, the height potential change of the pulse signal of synchronizing signal Sync0 and primary side is on the contrary.In the present embodiment, synchronizing signal Sync1 then is consistent with the height potential change of the pulse signal of primary side.That is to say that in the primary side turn-on cycle, synchronizing signal Sync1 can present high potential, but not electronegative potential.
Figure 11 demonstration utilizes secondary side synchronous rectifier controller of the present invention, converts the synchronizing signal Sync1 among Figure 10 the oscillogram of Dead Time control signal Comp with the control signal of the conducting state of control synchronous rectification switch 55 into.The embodiment that is different from Fig. 9 is that the mode that adopts trailing edge to trigger is controlled reset switch 426 conductings, to form sawtooth signal Ramp.Because the synchronizing signal Sync1 of present embodiment is consistent with the height potential change of the pulse signal of primary side; Present embodiment changes the mode that triggers with leading edge (Rising Edge); Produce 426 conductings of leading edge trigger impulse RTP control reset switch, to form sawtooth signal Ramp.The generation principle of the Dead Time control signal Comp of present embodiment and synchronous rectification control signal SRC, roughly the same with the embodiment of Fig. 6 and Fig. 9, do not give unnecessary details at this.
The present invention utilizes synchronizing signal Sync0, and the turn-on cycle that Sync1 defines produces sawtooth signal Ramp, the crest voltage of collocation peak sample technology acquisition sawtooth signal Ramp, and set a reference bias Vr, to produce Dead Time control signal Comp.Therefore, the present invention can replace the digital control circuit of known complicacy.Secondly, the technological crest voltage that is captured of peak sample can change in response to the length in real work cycle because the present invention arranges in pairs or groups, thereby can be in response to the change in real work cycle.Dead Time td length then can produce elements such as electric capacity 422, maintenance electric capacity 442 and set through sawtooth waveforms.In sum, secondary side synchronous rectifier controller of the present invention is a kind of control mode of prediction type, captures the sawtooth signal Ramp in last cycle, to set Dead Time td.Therefore, can be applicable under the condition that the operating frequency deviation is big, the power supply voltage variation scope is big, to reach high efficiency power supply control.
But; The above is merely preferred embodiment of the present invention, when not limiting the scope that the present invention implements with this; Be allly to change and revise, all belong in the scope that patent of the present invention contains according to claim protection range of the present invention and the simple equivalent done of invention description.Arbitrary embodiment of the present invention in addition or claim must not reach disclosed whole purposes or advantage or characteristics.In addition, summary part and title only are the usefulness that is used for assisting the patent document search, are not to be used for limiting claim protection range of the present invention.
Claims (20)
1. a secondary side synchronous rectifier controller in order to control at least one synchronous rectification switch, is characterized in that, this secondary side synchronous rectifier controller comprises:
One sawtooth generator receives a synchronous signal, to produce a sawtooth signal;
One peak sample unit captures a crest voltage of this sawtooth signal, produces the prediction reference voltage signal that a voltage progressively successively decreases according to this; And
One output control unit; Relatively this sawtooth signal and this prediction reference voltage signal; To produce the conducting state of this synchronous rectification switch of Dead Time control signal control; When the current potential of this sawtooth signal was higher than the current potential of this prediction reference voltage signal, this output control unit turn-offed this synchronous rectification switch.
2. secondary side synchronous rectifier controller as claimed in claim 1 is characterized in that, this sawtooth generator comprises:
One sawtooth waveforms produces electric capacity;
One charge power supply produces the electric capacity charging to this sawtooth waveforms, to produce this sawtooth signal; And
One reset switch produces the stored electric charge of electric capacity to discharge this sawtooth waveforms, and this reset switch is controlled by this synchronizing signal.
3. secondary side synchronous rectifier controller as claimed in claim 2 is characterized in that, this charge power supply is a constant current source or certain voltage source.
4. secondary side synchronous rectifier controller as claimed in claim 1 is characterized in that, this peak sample unit comprises:
One keeps electric capacity, in order to receive this sawtooth signal; And
One releasing member keeps the electric charge of electric capacity in order to release stored in this;
Wherein, this keeps this prediction reference voltage signal of high-pressure side output of electric capacity.
5. secondary side synchronous rectifier controller as claimed in claim 4 is characterized in that, this releasing member is a release impedance or a constant current source.
6. secondary side synchronous rectifier controller as claimed in claim 4; It is characterized in that; This peak sample unit more comprises a reference bias source, in order to drag down a stored voltage of this maintenance electric capacity, makes the maximum of this stored voltage this crest voltage less than this sawtooth signal.
7. secondary side synchronous rectifier controller as claimed in claim 1 is characterized in that, this synchronizing signal is the output signal of a primary side winding.
8. secondary side synchronous rectifier controller as claimed in claim 1 is characterized in that, this output control unit produces the conducting state of synchronous this synchronous rectification switch of rectification control signal control according to this dead band time control signal and this synchronizing signal.
9. the power-switching circuit with secondary side synchronous rectifier function is characterized in that, this power-switching circuit comprises:
One transformer, this transformer comprise a primary side winding and a primary side winding;
One synchronous rectifier switch is connected to this primary side winding;
One primary side synchronous rectifying controller, in order to control this synchronous rectification switch, this secondary side synchronous rectifier controller comprises:
One sawtooth generator receives a synchronous signal, to produce a sawtooth signal;
One peak sample unit captures a crest voltage of this sawtooth signal, produces according to this
Give birth to the prediction reference voltage signal that a voltage progressively successively decreases; And
One output control unit; Relatively this sawtooth signal and this prediction reference voltage signal; To produce the conducting state of this synchronous rectification switch of Dead Time control signal control; When the current potential of this sawtooth signal was higher than the current potential of this prediction reference voltage signal, this output control unit turn-offed this synchronous rectification switch.
10. power-switching circuit as claimed in claim 9 is characterized in that, this sawtooth generator comprises:
One sawtooth waveforms produces electric capacity;
One charge power supply produces the electric capacity charging to this sawtooth waveforms, to produce this sawtooth signal; And
One reset switch produces the stored electric charge of electric capacity to discharge this sawtooth waveforms, and this reset switch is controlled by this synchronizing signal.
11. power-switching circuit as claimed in claim 10 is characterized in that, this charge power supply one constant current source or certain voltage source.
12. power-switching circuit as claimed in claim 9 is characterized in that, this peak sample unit comprises:
One keeps electric capacity, in order to receive this sawtooth signal; And
One releasing member keeps the electric charge of electric capacity in order to release stored in this;
Wherein, this keeps this prediction reference voltage signal of high-pressure side output of electric capacity.
13. power-switching circuit as claimed in claim 12 is characterized in that, this releasing member is a release impedance or a constant current source.
14. power-switching circuit as claimed in claim 12 is characterized in that, this peak sample unit more comprises a reference bias source, in order to drag down a stored voltage of this maintenance electric capacity, makes the maximum of this stored voltage this crest voltage less than this sawtooth signal.
15. power-switching circuit as claimed in claim 9 is characterized in that, this secondary side synchronous rectifier controller comprises a power input, and this power input is connected to the auxiliary winding of a primary side.
16. power-switching circuit as claimed in claim 9 is characterized in that, this synchronizing signal is an output signal of this secondary survey winding.
17. a prediction type synchronous rectification control method in order to control at least one synchronous rectification switch of an exchange type power conversion circuit, is characterized in that, this prediction type synchronous rectification control method comprises the following steps: at least
According to a synchronous signal, produce identical sawtooth signal of one-period;
According to this crest voltage of this sawtooth signal,, produce the prediction reference voltage signal that a voltage progressively successively decreases in the following one-period of this sawtooth signal; And
Relatively this sawtooth signal of this prediction reference voltage signal and this following one-period is controlled the conducting state of this synchronous rectification switch to produce a Dead Time control signal.
18. prediction type synchronous rectification control method as claimed in claim 17 is characterized in that a maximum voltage of this prediction reference voltage signal is less than this crest voltage of corresponding this sawtooth signal.
19. like claim 17 a described prediction type synchronous rectification control method, it is characterized in that, utilize the step of this this synchronous rectification switch of dead band time control signal control to comprise:
Capture this synchronizing signal, this synchronizing signal definition has at least one primary side turn-on cycle;
Utilize this dead band time control signal, shorten the time span of this primary side turn-on cycle of corresponding this synchronizing signal; And
Utilize the conducting state of adjusted this this synchronous rectification switch of synchronizing signal control.
20. prediction type synchronous rectification control method as claimed in claim 17; It is characterized in that; Relatively this sawtooth signal of this prediction reference voltage signal and this following one-period is to produce the step of a Dead Time control signal; Be when the current potential of this prediction reference voltage signal is lower than this sawtooth signal of this following one-period, produce this dead band time control signal.
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102723856A (en) * | 2012-07-02 | 2012-10-10 | 矽力杰半导体技术(杭州)有限公司 | Synchronous rectifier control circuit and switch power supply employing same |
| CN105471286A (en) * | 2015-12-10 | 2016-04-06 | 无锡华润矽科微电子有限公司 | Synchronous rectification circuit, wireless charging system and synchronous rectification method |
| CN105529791A (en) * | 2014-09-28 | 2016-04-27 | 比亚迪股份有限公司 | Charging system based on secondary control and secondary control device thereof |
| CN105529799A (en) * | 2014-09-28 | 2016-04-27 | 比亚迪股份有限公司 | Charging system based on secondary control and secondary control device thereof |
| CN106411135A (en) * | 2015-07-31 | 2017-02-15 | 德州仪器公司 | Flyback converter with secondary side regulation |
| CN106533207A (en) * | 2015-09-15 | 2017-03-22 | 通嘉科技股份有限公司 | Synchronous rectifier used for power converter and operation method of synchronous rectifier |
| CN106817017A (en) * | 2015-11-30 | 2017-06-09 | 通嘉科技股份有限公司 | The method for controlling the secondary side idle time of power supply changeover device |
| CN108233450A (en) * | 2016-12-19 | 2018-06-29 | 中惠创智（深圳）无线供电技术有限公司 | A kind of resonance type wireless electric power system and its circuit of synchronous rectification |
| CN110521097A (en) * | 2017-05-03 | 2019-11-29 | 微芯片技术股份有限公司 | Zero dead-time control circuit |
| CN112205078A (en) * | 2018-05-28 | 2021-01-08 | 侯经权 | Universal light modulator |
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| TWI569562B (en) * | 2015-11-16 | 2017-02-01 | 通嘉科技股份有限公司 | Method for controlling a dead time of a secondary side of a power converter |
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Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102723856B (en) * | 2012-07-02 | 2014-06-25 | 矽力杰半导体技术(杭州)有限公司 | Synchronous rectifier control circuit and switch power supply employing same |
| CN102723856A (en) * | 2012-07-02 | 2012-10-10 | 矽力杰半导体技术(杭州)有限公司 | Synchronous rectifier control circuit and switch power supply employing same |
| CN105529791A (en) * | 2014-09-28 | 2016-04-27 | 比亚迪股份有限公司 | Charging system based on secondary control and secondary control device thereof |
| CN105529799A (en) * | 2014-09-28 | 2016-04-27 | 比亚迪股份有限公司 | Charging system based on secondary control and secondary control device thereof |
| CN105529799B (en) * | 2014-09-28 | 2018-12-21 | 比亚迪股份有限公司 | Charging system and its secondary control device based on secondary control |
| US11722067B2 (en) | 2015-07-31 | 2023-08-08 | Texas Instruments Incorporated | Flyback converter with secondary side regulation |
| CN106411135A (en) * | 2015-07-31 | 2017-02-15 | 德州仪器公司 | Flyback converter with secondary side regulation |
| CN106533207A (en) * | 2015-09-15 | 2017-03-22 | 通嘉科技股份有限公司 | Synchronous rectifier used for power converter and operation method of synchronous rectifier |
| CN106533207B (en) * | 2015-09-15 | 2019-02-05 | 通嘉科技股份有限公司 | Synchronous rectifier and its operating method applied to power adapter |
| CN106817017A (en) * | 2015-11-30 | 2017-06-09 | 通嘉科技股份有限公司 | The method for controlling the secondary side idle time of power supply changeover device |
| CN106817017B (en) * | 2015-11-30 | 2019-10-18 | 通嘉科技股份有限公司 | The method for controlling the secondary side idle time of power adapter |
| CN105471286A (en) * | 2015-12-10 | 2016-04-06 | 无锡华润矽科微电子有限公司 | Synchronous rectification circuit, wireless charging system and synchronous rectification method |
| CN108233450A (en) * | 2016-12-19 | 2018-06-29 | 中惠创智（深圳）无线供电技术有限公司 | A kind of resonance type wireless electric power system and its circuit of synchronous rectification |
| CN110521097B (en) * | 2017-05-03 | 2021-06-08 | 微芯片技术股份有限公司 | Zero dead time control circuit |
| CN110521097A (en) * | 2017-05-03 | 2019-11-29 | 微芯片技术股份有限公司 | Zero dead-time control circuit |
| CN112205078A (en) * | 2018-05-28 | 2021-01-08 | 侯经权 | Universal light modulator |
| CN112205078B (en) * | 2018-05-28 | 2024-01-26 | 侯经权 | Universal dimmer |
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