CN208143094U - Synchronous rectification inverse-excitation type DC-DC power conversion equipment - Google Patents

Abstract

The utility model discloses a kind of synchronous rectification inverse-excitation type DC-DC power conversion equipments, the utility model is by opening primary side power switch tube once first with a narrow pulse signal before primary side power switch tube is normally opened, secondary synchronous rectifier is turned off, former secondary side, which is reduced, by the width or amplitude that control burst pulse is total to alive amplitude, to reduce common electric current bring circuit loss, prevent switching device from damaging.Therefore the control circuit of the utility model and conversion equipment work normally synchronous rectification inverse-excitation type DC-to-dc converter can in discontinuous conduct mode, critical continuous conduction mode and continuous mode.

Description

Synchronous rectification inverse-excitation type DC-DC power conversion equipment

Technical field

The utility model patent is related to a kind of DC-DC power conversion equipment, and it is continuous, interrupted to be particularly suitable for electric current Or the inverse-excitation type DC-DC power conversion equipment with synchronous rectification of the various operating modes such as critical discontinuous.

Background technique

DC/DC conversion is most basic one of transformation of electrical energy form.Flyback converter is since its topology is simple, first device The features such as part is few, is widely used, usually in 100~200W or less in small-power switching power-supply.The loss of flyback converter The main loss including primary side switch pipe, transformer loss, the loss of absorbing circuit and the loss of secondary side rectifier.Wherein, The loss of output end rectifier is one of dominant loss of inverse excitation type converter, in the case that low-voltage, high current output, it is whole The specific gravity that the loss of flow tube accounts for is especially prominent.

In order to reduce the loss of rectifying tube, a kind of main means are synchronous rectifications.Fig. 1 show one kind and uses The inverse-excitation type DC-DC power conversion equipment of synchronous rectification, shown in synchronous commutating control circuit 100 be it is a kind of most The simplified pinciple figure of the synchronous commutating control circuit of the common prior art.

As shown in Figure 1, when primary side power switch tube Q1 is turned off, energy is transferred to secondary side from the primary side of transformer T, synchronizes whole Flow tube Q_SRBody diode be connected afterflow, synchronous rectifier Q_SRDrain electrode VD become negative pressure.When VD voltage is lower than reference voltage When VTH1,101 output switching activity of comparator makes 103 set of trigger, the output of trigger 103 after the driving of driving circuit 104, The control signal Vg_SR of output synchronous rectifier controls synchronous rectifier Q_SRConducting.Synchronous rectifier Q_SRConducting can be significantly The conduction voltage drop for reducing output rectifier achievees the purpose that reduce loss, improve efficiency.As freewheel current reduces, VD voltage It increases, when VD voltage is higher than reference voltage VTH2,102 output switching activity of comparator resets trigger 103, and control synchronizes whole Flow tube Q2 shutdown.In addition, being also added into minimum turn-on time circuit 107 and/or door 108 in synchronous commutating control circuit 100 To prevent the oscillation of VD waveform from leading to synchronous rectifier Q_SRControl signal Vg_SR when opening accidentally turn off, separately joined Minimum turn-off time circuit 105 and with door 106 be arranged a minimum turn-off time, avoid synchronous rectifier Q_SRAfter shut-off again It is open-minded.

Using synchronous rectification control mode shown in Fig. 1, due to detecting that VD reaches benchmark from synchronous commutating control circuit 100 Voltage is to synchronous rectifier control signal overturning, and control circuit has inevitably delay, including the open-minded of synchronous rectifier Be delayed Td1 and shutdown delay Td2, as shown in Figures 2 and 3.Wherein Fig. 2 show the work of flyback converter shown in Fig. 1 in electric current Main waveform when discontinuous mode or critical discontinuous mode, Fig. 3 show the work of flyback converter shown in Fig. 1 in the electric current progressive die Main waveform when formula.

By Fig. 2 it can be seen that, when VD voltage reaches benchmark VTH2, the synchronous rectifier Q after delay Td2_SRControl It is low level, synchronous rectifier Q that signal Vg_SR is overturn from high level_SRShutdown, body diode flow through secondary current.Due to anti- Exciting converter works in discontinuous conduct mode or critical discontinuous mode, and secondary current descending slope is smaller, therefore synchronous rectification Pipe Q_SRTurn-off time can control before secondary current zero crossing, therefore synchronous rectifier Q will not occur_SRWith primary side function Rate switching tube Q1's is common.

As shown in figure 3, under continuous current mode, it is open-minded in t3 moment primary side power switch tube Q1, flow through synchronous rectification Pipe Q_SRElectric current start to decline rapidly with larger slope, corresponding VD voltage is begun to ramp up；At the t4 moment, VD voltage reaches benchmark VTH2, using the t5 timing synchronization rectifying tube Q after delay Td2_SRJust turn off.It can be seen that in this section of section t3 to t5, Primary side power switch tube Q1 and synchronous rectifier Q_SRIt is at common state, therefore biggish common electric current can be generated, is made Flyback converter operation irregularity, or even circuit is caused to damage.

Therefore, existing synchronous rectification control technology shown in FIG. 1 is only applicable to flyback converter work in discontinuous current Mode or critical discontinuous mode have biggish limitation.And under many applicable cases or operating condition, in order to optimize device effect Rate, it may be desirable to design flyback converter and enter continuous current mode.

For the flyback converter of continuous current mode, a kind of existing solution is will be former using optocoupler or magnetic cell The signal of side switching tube is transferred to transformer secondary, then through being used to control secondary synchronous rectifier after certain logical process. But due to transmission be high-frequency pulse signal, optocoupler will be using expensive high speed photo coupling, and magnetic cell price is higher, because The method of this this isolation transmission synchronous rectifier control signal is in industry using relatively fewer.

Utility model content

In order to solve problem above, the utility model provides a kind of synchronous rectification flyback based on the driving of primary side dipulse Formula DC-DC power control circuit and conversion equipment.

A kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment, including circuit of reversed excitation, synchronous rectification inverse-excitation type are straight Stream-DC power control circuit and synchronous commutating control circuit；

Electricity occurs for wherein synchronous rectification inverse-excitation type DC-DC power control circuit, including output regulating circuitry, dipulse Road and drive module；Wherein, circuit of reversed excitation feedback signal generates the adjustable simple venation of duty ratio to output regulating circuitry based on the received Rush periodic signal；Dipulse occurs the circuit pulse periodic signal that output regulating circuitry exports based on the received and generates at one The dual pulse cycle signal of narrow wide two pulses in switch periods；Double arteries and veins of circuit output are occurred for dipulse by drive module It rushes periodic signal and carries out processing and driving capability enhancing to drive circuit of reversed excitation primary side switch pipe；

The circuit of reversed excitation includes an input circuit, an output circuit and a transformer；The input circuit Including primary side power switch tube, DC input voitage is received, gives transformer-supplied, primary side power switch tube and transformer primary side function Rate windings in series；Output circuit includes secondary synchronous rectifier and output capacitance, the secondary side power winding coupling with the transformer It closes, output port of the energy that the transformer is discharged during primary side power switch tube shutdown in the output circuit A direct current is generated, load is supplied to；

The synchronous rectification inverse-excitation type DC-DC power control circuit is generated according to the feedback signal for receiving circuit of reversed excitation Dual pulse cycle signal is to realize the control to circuit of reversed excitation primary side power switch tube；

The synchronous commutating control circuit is by the pressure drop between detection secondary synchronous rectifier hourglass source electrode to generate secondary side The control signal of synchronous rectifier.

Wherein, in a switch periods, before the narrow pulse signal of the dual pulse cycle signal appears in broad pulse, The width of burst pulse is much smaller than switch periods, and the dead time between burst pulse failing edge and broad pulse rising edge is much smaller than switch Period；

Preferably, the synchronous rectification inverse-excitation type DC-DC power control circuit can be selected according to circuit operating pattern It selects and falls internal dipulse generation circuits bypass become the synchronous rectification inverse-excitation type DC-DC power control circuit For conventional inverse-excitation type DC-DC power mono pulse control circuit.

Preferably, the DC input voitage of the input circuit be the DC voltage that directly exports of DC power supply or other The DC voltage or the DC input voitage of conversion circuit output are the alternating voltage of power grid by diode rectification electricity The constant DC voltage or sinusoidal half-wave voltage of road output.

Preferably, the circuit of reversed excitation and synchronous commutating control circuit, specially：

Transformer primary side one terminates DC input voitage anode, the other end and the primary side power switch tube of transformer primary side Drain electrode connection, the source electrode of first switch tube connect DC input voitage cathode, one end of transformer secondary and synchronous rectification control electricity The drain electrode connection at the end VD, secondary synchronous rectifier on road, the grid of secondary synchronous rectifier and the VG of synchronous commutating control circuit End connection, the other end of transformer secondary are connect with one end of one end of capacitor Co, load, the other end and the load of capacitor Co The end GND of the other end, the source electrode of secondary synchronous rectifier and synchronous commutating control circuit connects.

Preferably, the circuit of reversed excitation and synchronous commutating control circuit, specially：

The drain electrode of primary side power switch tube connects DC input voitage anode, and transformer primary side one terminates primary side power switch tube Source electrode, another termination DC input voitage cathode of transformer primary side, one end of transformer secondary and synchronous rectification control electricity The drain electrode connection at the end VD, secondary synchronous rectifier on road, the grid of secondary synchronous rectifier and the VG of synchronous commutating control circuit End connection, the other end of transformer secondary are connect with one end of one end of capacitor Co, load, the other end and the load of capacitor Co The end GND of the other end, the source electrode of secondary synchronous rectifier and synchronous commutating control circuit connects.

The principles of the present invention are：For synchronous rectification inverse-excitation type DC-to-dc converter, when its work is in electric current Under continuous state, secondary current just declines after being opened due to primary side power switch tube, conventional detection pair side is synchronized whole The negative pressure of flow tube both end voltage reaches the amplitude of certain threshold value to turn off the control mode of synchronous rectifier, due to secondary side synchronize it is whole Flow tube control circuit unavoidably generated in detection and signals transmission delay generated so as to cause former secondary side it is larger common Electric current.The utility model proposes synchronous rectification inverse-excitation type DC-DC power control circuit and conversion equipment pass through in primary side Power switch tube first with a narrow pulse signal opens primary side power switch tube once before normally opening, and secondary side is same Rectifying tube shutdown is walked, former secondary side is reduced by the width or amplitude that control burst pulse and is total to alive amplitude, to reduce common Electric current bring circuit loss, prevents switching device from damaging.Therefore the control circuit of the utility model and conversion equipment make together Step rectification inverse-excitation type DC-to-dc converter can normal work in discontinuous conduct mode, critical continuous conduction mode and continuous mode Make.

Circuit structure and its implementation used by the utility model, there is clear advantage compared with the existing technology；Only Traditional pulse flyback control circuit need to be improved to the utility model proposes control circuit, without increasing additional circuit Cost realizes low common electric current, compatible discontinuous conduct mode, electricity using the secondary side synchronous rectification control technology of the prior art The synchronous rectification inverse-excitation type DC-to-dc converter of critical discontinuous mode and continuous current mode is flowed, control circuit is realized simply, And circuit of single-chip integrated realization can be used.

Detailed description of the invention

The synchronous rectification inverse-excitation type DC-DC that Fig. 1 shows a kind of synchronous commutating control circuit using the prior art turns Parallel operation；

Fig. 2 shows key waveforms of the work of circuit shown in Fig. 1 under discontinuous conduct mode；

Fig. 3 shows key waveforms of the work of circuit shown in Fig. 1 under continuous current mode；

Fig. 4 shows the synchronous rectification inverse-excitation type DC-DC power control circuit schematic block diagram of the utility model；

Fig. 5 shows the output in the synchronous rectification inverse-excitation type DC-DC power control circuit of the utility model and adjusts electricity A kind of specific embodiment schematic diagram on road；

Fig. 6 shows the generation of the dipulse in the synchronous rectification inverse-excitation type DC-DC power control circuit of the utility model A kind of specific embodiment schematic diagram of circuit；

Fig. 7 shows the generation of the dipulse in the synchronous rectification inverse-excitation type DC-DC power control circuit of the utility model Key waveforms in a kind of specific embodiment schematic diagram of circuit；

Fig. 8 shows the first specific implementation of the synchronous rectification inverse-excitation type DC-DC power conversion equipment of the utility model It illustrates and is intended to；

Fig. 9 shows the first specific implementation of the synchronous rectification inverse-excitation type DC-DC power conversion equipment of the utility model The first control mode specific waveform of the example work under continuous current mode；

Figure 10 shows the first specific implementation of the synchronous rectification inverse-excitation type DC-DC power conversion equipment of the utility model Second control mode specific waveform of the example work under continuous current mode；

Figure 11 shows the electricity of the second specific embodiment of the synchronous rectification inverse-excitation type DC-to-dc converter of the utility model Road schematic diagram；

Specific embodiment

The utility model is described in detail below in conjunction with attached drawing.By being retouched to the utility model specific embodiment It states, can more easily understand the feature and details of the utility model.Well known embodiment not detailed herein and behaviour Make means, in order to avoid obscuring various implementer's cases of the utility model, still, to those skilled in the art, lacks One or more concrete details or component do not influence understanding and implementation to the utility model.

" embodiment " or " one embodiment " described in this specification refer to that is described in conjunction with the embodiments is included in this reality With specific features, structure, embodiment and the feature at least one novel embodiment.Therefore, in specification different places When mentioning " in one embodiment ", not necessarily referring to the same embodiment.These features, structure or characteristic can be with any conjunctions Suitable mode combines in one or more embodiments.

The synchronous rectification inverse-excitation type DC-DC power control circuit schematic block diagram of the utility model, institute are shown with reference to Fig. 4 The synchronous rectification inverse-excitation type DC-DC power control circuit 300 for showing the utility model includes output regulating circuitry 301, Shuan Mai Circuit 302 and drive module 303 occur for punching；Wherein, output regulating circuitry 301 exports pulse periodic signal based on the feedback signal Vga, dipulse occur the pulse periodic signal Vga that output regulating circuitry 301 exports based on the received of circuit 302 and export double arteries and veins Rush periodic signal Vgb, drive module 303 by the dual pulse cycle signal Vgb that dipulse generation circuit 302 exports carry out processing and The control signal Vg1 of output driving circuit of reversed excitation primary side switch pipe after driving capability enhancing.

Fig. 5 shows the output in the synchronous rectification inverse-excitation type DC-DC power control circuit of the utility model and adjusts electricity A kind of specific embodiment schematic diagram on road 301, this specific embodiment are classical peak-current mode control circuit, are suitable for anti- Excitation type converter or other DC-DC converters.The specific embodiment of shown output regulating circuitry 301 includes error amplifier 3011, compensation network 3012, voltage reference 3013, comparator 3014, clock signal 3015 and rest-set flip-flop 3016, wherein error The negative input end of amplifier 3011 receives the output feedback signal FB of reverse excitation circuit, the positive input termination of error amplifier 3011 Voltage reference 3013, negative input end, another termination error amplifier of a termination error amplifier 3011 of compensation network 3012 3011 output end, the output end of error amplifier 3011 also connect the negative input end of comparator 3014, comparator 3014 it is just defeated Enter the current feedback signal CS that end receives reflection reverse excitation circuit primary circuit switching tube current information, the output of comparator 3014 The reset terminal Reset of rest-set flip-flop 3016 is terminated, the set end Set of rest-set flip-flop 3016 connects clock signal 3015, rest-set flip-flop 3016 output end exports pulse periodic signal Vga.

Fig. 5 shows the output in the synchronous rectification inverse-excitation type DC-DC power control circuit of the utility model and adjusts electricity A kind of working principle of the specific embodiment on road 301 approximately as：The negative input end of error amplifier 3011 receives inverse-excitation type electricity The output feedback signal FB on road, the voltage reference 3013 connect with the positive input terminal of error amplifier 3011 are compared, the two Error signal compensated network 3012 amplification after obtain the error amplification signal of DC level and be sent to comparator 3014 Negative input end, the electric current of the received reflection reverse excitation circuit primary circuit switching tube current information of the positive input terminal of comparator 3014 Feedback signal CS is compared with the error amplification signal of 3014 negative input end of comparator, when the current feedback signal CS is touched To the error amplification signal, the output end level signal of comparator 3014 is high level by low level overturning, passes through comparator The signal Vga that rest-set flip-flop 3016 exports is reset to by the reset terminal Reset of the rest-set flip-flop 3016 of 3014 output end connection Low level, and when 3016 set end Set of rest-set flip-flop detects that the clock signal 3015 being attached thereto is high level, RS triggering The signal Vga set that device 3016 exports is high level, therefore the output end of rest-set flip-flop 3016 exports a period and clock signal 3015 periods identical pulse periodic signal Vga.When the output of reverse excitation circuit changes, output feedback signal FB hair Raw corresponding change, to change the direct current level values of the error amplification signal, further changes pulse periodic signal Vga's Duty ratio realizes the adjusting of the output to reverse excitation circuit, achievees the purpose that pressure stabilizing or current stabilization.As those skilled in the art Member should working principle to the output regulating circuitry 301 it is very familiar, be not detailed herein.

Those skilled in the art should also be noted that the synchronous rectification inverse-excitation type DC-DC power control of the utility model Output regulating circuitry 301 in circuit processed can not only use the peak-current mode control circuit of classics shown in fig. 5, may be used also Using the control circuit such as voltage mode control of the DC-DC voltage conversion equipment of the control model of other well known technology, put down The utility model output regulating circuitry is realized in equal Controlled in Current Mode and Based, constant turn-on time control and critical conduction mode control etc. 301 said function, no longer describes one by one here.

The dipulse in the synchronous rectification inverse-excitation type DC-DC power control circuit of the utility model is shown with reference to Fig. 6 A kind of specific embodiment schematic diagram of circuit 302 occurs, the specific embodiment that circuit 302 occurs for shown dipulse prolongs including first When circuit 3021, phase inverter 3022, with door 3023, the second delay circuit 3024 or door 3025, wherein the first delay circuit 3021 Input terminal receive external signal Vga, the output end of the first delay circuit 3021 connects the input terminal of phase inverter 3022, phase inverter One input terminal of 3022 output termination and door 3023 receives external signal Vga with another input terminal of door 3023, with door 3023 output termination or an input terminal of door 3025, the input terminal of the second delay circuit 3024 receive external signal Vga, the The output end output signal Vgb of the output termination of two delay circuits 3024 or another input terminal of door 3025 or door 3025.

The dipulse in the utility model synchronous rectification inverse-excitation type DC-DC power control circuit with reference to shown in Fig. 7 A kind of key waveforms of specific embodiment of circuit 302 occur, the pulse period letter that circuit 302 inputs occurs for the dipulse Number Vga obtains signal V1 after the delay of the first delay circuit 3021, after inverted 3022 reverse phase of device of signal V1 and pulse Periodic signal Vga by with 3023 phase of door and obtain signal V3, pulse periodic signal Vga is delayed through the second delay circuit 3024 Signal V2, signal V2 and signal V3 warp or 3025 phase of door are obtained later or obtain signal Vgb later.As seen from Figure 7, double arteries and veins The function that circuit 302 occurs for punching is that the monocycle signal Vga of input is converted to narrow wide two arteries and veins in a switch periods The dual pulse cycle signal Vgb of punching.

It should be known to those skilled in the art that the specific embodiment that circuit 302 occurs for the dipulse shown in Fig. 7 is only used to Illustrate to realize that a kind of possible implementation of 302 function of circuit occurs for dipulse, circuit occurs for the dipulse in the utility model 302 include but are not limited to specific embodiment shown in Fig. 7, the not detailed double arteries and veins of specific embodiment shown in Fig. 7 All possible embodiments of circuit 302 occur for punching, and other logic circuits can be used also to realize in those skilled in the art Same function.

With reference to the first tool of the synchronous rectification inverse-excitation type DC-DC power conversion equipment of the utility model shown in Fig. 8 Body embodiment schematic diagram, the synchronous rectification inverse-excitation type DC-DC power conversion equipment includes circuit of reversed excitation 200 and this is practical The synchronous rectification inverse-excitation type DC-DC power control circuit 300 of novel proposition, further, the synchronous rectification inverse-excitation type is straight Stream-apparatus for converting DC power further includes synchronous commutating control circuit 100.

Wherein, the circuit of reversed excitation 200 includes：

Transformer T contains at least one primary side power winding Wp and a pair side power winding Ws；

Input circuit, including primary side power switch tube Q1 receive DC input voitage Vin；Two of the input circuit Input terminal is respectively the Same Name of Ends of the primary side power winding Wp of transformer T and the source electrode of primary side power tube Q1, the primary side of transformer T The anode of the termination DC input voitage Vin of the same name of power winding Wp, the source electrode of primary side power tube Q1 meet DC input voitage Vin Negative terminal, the drain electrode of primary side power switch tube Q1 connects the different name end of the transformer T primary side power winding Wp, primary side power switch The grid of pipe Q1 receives control signal Vg1；Preferably, sampling electricity can be also sealed between the source electrode of primary side power tube Q1 and primary side ground Resistance is supplied to synchronous rectification inverse-excitation type DC-DC power control circuit 300 to sample primary side switch electric current as feedback signal；

Output circuit, including secondary synchronous rectifier Q_SRWith output capacitance Co, the secondary side power winding Ws of the transformer T Different name termination output capacitance Co anode, the secondary synchronous rectification in the termination pair of the same name of power winding Ws of the transformer T Pipe Q_SRDrain electrode, the secondary synchronous rectifier Q_SRSource electrode meet the cathode of output capacitance Co, the secondary synchronous rectifier Q_SR Grid receive control signal Vg_SR.

100 1 input terminals of the synchronous commutating control circuit connect secondary synchronous rectifier Q_SRDrain electrode, another is defeated Enter end connection secondary synchronous rectifier Q_SRSource electrode, output end connect secondary synchronous rectifier Q_SRGrid, it is described synchronize it is whole The output end of flow control circuit 100 exports secondary synchronous rectifier Q_SRGrid control signal Vg_SR.

The synchronous rectification inverse-excitation type DC-DC power control circuit 300 receives the feedback signal of circuit of reversed excitation, output Control signal Vg1.

For the convenience of description, the number of turns and pair side power winding Ws that the turn ratio n for defining transformer T is primary side power winding Wp The ratio between the number of turns, be also in this way, no longer individually definition in the other embodiments of this specification.

With reference to the first specific implementation of the synchronous rectification inverse-excitation type DC-DC power conversion equipment of Fig. 9 the utility model The synchronous rectification of example the first control mode specific waveform of the work under continuous current mode and the prior art shown in FIG. 1 Control circuit 100：

At the t1 moment, primary side power switch tube Q1 shutdown is stored in energy transfer in transformer T to output loop, original Side electric current Ip decline, secondary current Is rise, secondary synchronous rectifier Q_SRBody diode be conducted through secondary current Is so that Secondary synchronous rectifier Q_SRThe voltage Vds_QSR at both ends is equal to the pressure drop of negative body diode.Synchronous rectification according to figure 1 The working principle of control circuit 100 is it is found that due to secondary synchronous rectifier Q_SRBody diode pressure drop lower than synchronous rectification control The internal reference voltage VTH1 of circuit 100,101 output switching activity of comparator make 103 set of trigger, the output warp of trigger 103 Driving circuit 104 sends secondary synchronous rectifier Q to_SRGrid.Considering 100 internal logic circuit of synchronous commutating control circuit At the t2 moment after the delay Td1 of generation, it is high level, control that secondary synchronous rectifier, which controls signal Vg_SR by low level overturning, Secondary synchronous rectifier Q processed_SRConducting.In secondary synchronous rectifier Q_SRIt is secondary as secondary current Is electric current declines during conducting Synchronous rectifier Q_SRThe voltage Vds_SR at both ends rises, but since circuit work is in electric current continuous state, Vds_SR is not up to To reference voltage VTH2；At the t3 moment, the control signal Vg1 of primary side power switch tube Q1 becomes high level, controls primary side power Switch Q1 conducting, primary side power switch tube Q1 both end voltage Vds_Q1 decline rapidly, secondary synchronous rectifier Q_SRThe voltage at both ends Vds_SR also accordingly rises rapidly higher than reference voltage VTH2, and the output of comparator 102 inside synchronous commutating control circuit 100 is turned over Turn, reset trigger 103, the output of trigger 103 sends secondary synchronous rectifier Q to through driving circuit 104_SRGrid, During this period, due to the presence of transformer leakage inductance, primary current Ip starts with the rising of certain slope, and secondary current Is is with certain oblique Rate decline.At the t4 moment, the control signal Vg1 of primary side power switch tube Q1 becomes low level again, controls primary side power switch Q1 shutdown, primary side power switch tube Q1 both end voltage Vds_Q1 rise rapidly, secondary synchronous rectifier Q_SRThe voltage Vds_ at both ends SR accordingly declines rapidly, and primary side energy transfer rises to secondary side, secondary current Is；Considering in synchronous commutating control circuit 100 T5 moment after the delay Td2 that portion's logic circuit generates, secondary synchronous rectifier control signal Vg_SR by high level overturning and are Low level controls secondary synchronous rectifier Q_SRShutdown, secondary current Is is from secondary synchronous rectifier Q_SRBody diode flow through, Vds_SR is lower than internal reference voltage VTH1, but since the shielding that synchronous rectification controls 100 minimum turn-off time circuits 105 is made With synchronous rectifier Q_SRStill it is held off.At the t6 moment, the control signal Vg1 of primary side power switch tube Q1 becomes high again Level, primary side power switch tube Q1 is open-minded, and circuit of reversed excitation enters normally mode.

By analyzing above as it can be seen that under continuous current mode, conventional synchronization rectifies inverse-excitation type DC-DC power converting means Set middle transformer primary side power switch tube Q1 and synchronous rectifier Q_SRThe common time be equal to synchronous commutating control circuit 100 inside The delay Td2 that logic circuit generates, and in the present invention, if the of the control signal Vg1 of primary side power switch tube Q1 The width Tg11 of one narrow pulse signal is less than the delay Td2 that 100 internal logic circuit of synchronous commutating control circuit generates, then originally In the synchronous rectification inverse-excitation type DC-DC power conversion equipment of utility model transformer primary side power switch tube Q1 with it is synchronous whole Flow tube Q_SRThe common time be equal to Tg11.Therefore can be reduced by designing relatively narrow Tg11 former secondary-side switch pipe it is common when Between, to reduce common electric current, circuit loss is reduced, prevents circuit components from damaging.

Further, due to the conducting resistance of power switch tube such as MOSFET and the received control signal voltage amplitude of its grid Correlation, in certain gate voltage range, the amplitude for reducing grid control signal can make the electric conduction of power switch tube Resistance increases.Therefore, it is improved by first narrow pulse signal of the control signal Vg1 to primary side power switch tube Q1, it can Obtain the first specific embodiment work of the synchronous rectification inverse-excitation type DC-DC power conversion equipment of the utility model shown in Figure 10 Make the specific waveform of second of control mode under continuous current mode, wherein dual pulse cycle signal Vg1 shown in Fig. 10 is same Sample can be obtained by synchronous rectification inverse-excitation type DC-DC power control circuit 300.

With reference to Figure 10, be connected in t3 moment primary side power switch tube Q1, since Vg1 amplitude is lower, primary side power switch tube The conducting resistance of Q1 is larger, therefore the voltage Vds_Q1 descending slope at the both ends primary side power switch tube Q1 is smaller, and secondary side synchronizes whole Flow Q_SRThe voltage Vds_SR rate of rise at both ends is also smaller, the rate of rise of primary current Ip and the descending slope of secondary current Is Also relatively small；When Vds_SR rises above reference voltage VTH2, the comparator 102 inside synchronous commutating control circuit 100 Output switching activity, resets trigger 103, and the output of trigger 103 sends secondary synchronous rectifier Q to through driving circuit 104_SR's Grid；At the t4 moment, Vg1 becomes low level, primary side power switch tube Q1 shutdown, the both ends primary side power switch tube Q1 from high level Voltage Vds_Q1 rises, secondary synchronous rectifier Q_SRThe voltage Vds_SR at both ends accordingly declines；Considering synchronous rectification control electricity T5 moment after the delay Td2 that 100 internal logic circuit of road generates, secondary synchronous rectifier control signal Vg_SR by high electricity Flat overturning is low level, controls secondary synchronous rectifier Q_SRShutdown.At the t6 moment, the control signal of primary side power switch tube Q1 Vg1 becomes high level again, and primary side power switch tube Q1 is open-minded, and circuit of reversed excitation enters normally mode.

First specific implementation of the synchronous rectification inverse-excitation type DC-DC power conversion equipment of the utility model shown in Figure 10 Compared to for the first control mode more shown in Fig. 9, the two exists second of control mode under continuous current mode for example work To secondary synchronous rectifier Q_SRControl basic principle it is identical, unlike primary side power switch tube under second of control mode The voltage Vds_Q1 at the both ends Q1 in primary side power switch tube Q1 conducting section (t3-t4) for the first time falls amplitude smaller, former pair side Alive amplitude is also smaller altogether, therefore the switching loss of primary side power switch tube Q1 and on-state loss are reduced relatively.

Figure 11 is the circuit of the second specific embodiment of the synchronous rectification inverse-excitation type DC-to-dc converter of the utility model Schematic diagram, the synchronous rectification inverse-excitation type DC-to-dc converter include circuit of reversed excitation 200 with the utility model proposes it is synchronous Rectify inverse-excitation type DC-DC power control circuit 300.Further, the synchronous rectification inverse-excitation type DC-DC power conversion Device further includes synchronous commutating control circuit 100.

Wherein, the circuit of reversed excitation 200 includes：

Transformer T includes primary side power winding Wp and pair side power winding Ws；

Input circuit, including primary side power switch tube Q1 receive DC input voitage；Two inputs of the input circuit End is respectively the different name end of the drain electrode of primary side power switch tube Q1 and the primary side power winding Wp of transformer T, primary side power switch The drain electrode of pipe Q1 connects the anode of DC input voitage Vin, the different name termination direct current input electricity of the primary side power winding Wp of transformer T The negative terminal of Vin is pressed, the source electrode of primary side power switch tube Q1 is with connecing Same Name of Ends and the primary side of the transformer primary side power winding, former The grid of side power switch tube Q1 receives control signal Vg1；Preferably, the source electrode of primary side power tube Q1 and transformer primary side power Sampling resistor can be also sealed between the Same Name of Ends of winding is supplied to synchronous rectification to sample primary side switch electric current as feedback signal Inverse-excitation type DC-DC power control circuit 300.

Output circuit, including secondary synchronous rectifier Q_SRWith output capacitance Co, the secondary side power winding Ws of the transformer T Different name termination output capacitance Co anode, the secondary synchronous rectification in the termination pair of the same name of power winding Ws of the transformer T Pipe Q_SRDrain electrode, the secondary synchronous rectifier Q_SRSource electrode meet the cathode of output capacitance Co, the secondary synchronous rectifier Q_SR Grid receive control signal Vg_SR.

100 1 input terminals of the synchronous commutating control circuit connect secondary synchronous rectifier Q_SRDrain electrode, another is defeated Enter end connection secondary synchronous rectifier Q_SRSource electrode, output end connect secondary synchronous rectifier Q_SRGrid, it is described synchronize it is whole The output end of flow control circuit 100 exports secondary synchronous rectifier Q_SRGrid control signal Vg_SR.

The synchronous rectification inverse-excitation type DC-DC power control circuit 300 receives the feedback signal of circuit of reversed excitation, output Control signal Vg1.

Second specific embodiment of the synchronous rectification inverse-excitation type DC-to-dc converter of the utility model shown in Figure 11 with The difference of synchronous rectification inverse-excitation type first specific embodiment of DC-to-dc converter of the utility model shown in Fig. 8 is only that The control mode of the structure different from of circuit of reversed excitation, the course of work and secondary synchronous rectifier is essentially identical, no longer superfluous here It states.

The synchronous rectification inverse-excitation type DC-DC power conversion equipment of the utility model works in discontinuous conduct mode or electricity When flowing critical discontinuous mode, the secondary synchronous rectification when synchronous commutating control circuit 100 will be secondary before first high level of Vg1 Pipe Q_SRShutdown, therefore, the synchronous rectification inverse-excitation type DC-DC power conversion equipment of the utility model in discontinuous conduct mode or Electric current critical discontinuous mode still can work normally, and not do detailed analysis here.Further, due to discontinuous conduct mode or electricity Synchronous rectification inverse-excitation type DC-DC power conversion equipment is not present that former secondary-side switch pipe is common to ask under stream critical discontinuous mode Topic, it is also conceivable for a person skilled in the art that in the synchronous rectification inverse-excitation type DC-DC power conversion equipment of the utility model Select in this mode by the utility model proposes synchronous rectification inverse-excitation type DC-DC power control circuit 300 in it is double Pulse generating circuit 302 bypasses that synchronous rectification inverse-excitation type DC-DC power control circuit 300 is made to become conventional same The mono pulse control circuit of step rectification inverse-excitation type DC-DC power conversion equipment, device still work normally.

The above-mentioned detailed description of the utility model embodiment be not exhaustion or for the utility model to be limited in It is above-mentioned specific formal.While the above-mentioned specific embodiment and example for illustrating the utility model with schematic purpose, this Field technical staff will appreciate that carries out various equivalent modifications in the scope of the utility model.

The utility model enlightenment provided here is not necessarily applied in above system, is also applied to other In system.The element of above-mentioned various embodiments and effect can be combined to provide more embodiments.

It can be modified according to above-mentioned detailed description to the utility model, description above describe the utility model No matter specific embodiment and while describe anticipated optimal set mode, hereinbefore occur how being described in detail, can also It is implemented in numerous ways the utility model.The details of foregoing circuit structure and its control mode is executed in details at it and can be carried out Considerable variation, however it is still contained in the utility model disclosed herein.

It should be noted that the used special art in the certain features or scheme for illustrating the utility model as described above Language should not be taken to indicate to redefine the term herein to limit the certain specific of the utility model relevant to the term Feature, feature or scheme.In short, should not will be construed to that this is practical new in term used in appended claims Type is limited to specific embodiment disclosed in specification, unless above-mentioned detailed description part explicitly defines these terms.Cause This, the actual range of the utility model not only includes the disclosed embodiments, further include under claims implement or Execute all equivalent schemes of the utility model.

While certain schemes of the utility model are described in the form of certain specific rights requirements below, utility model People has thought over many claim forms of the various schemes of the utility model.Therefore, utility model people, which is retained in, submits Shen Please increase the right of accessory claim afterwards, to relate other sides of the utility model in the form of these accessory claims Case.

Claims (6)

1. synchronous rectification inverse-excitation type DC-DC power conversion equipment, it is characterised in that：It is anti-including circuit of reversed excitation, synchronous rectification Swash formula DC-DC power control circuit and synchronous commutating control circuit；

Wherein synchronous rectification inverse-excitation type DC-DC power control circuit, including output regulating circuitry, dipulse occur circuit and Drive module；Wherein, circuit of reversed excitation feedback signal generates duty ratio adjustable pulse week to output regulating circuitry based on the received Phase signal, dipulse occur the circuit pulse periodic signal that output regulating circuitry exports based on the received and generate in a switch The dual pulse cycle signal of narrow wide two pulses in period；The dipulse week of circuit output is occurred for dipulse by drive module Phase signal carries out processing and driving capability enhancing to drive circuit of reversed excitation primary side switch pipe；

The circuit of reversed excitation includes an input circuit, an output circuit and at least one transformer；The input circuit Including primary side power switch tube, DC input voitage is received, gives transformer-supplied, primary side power switch tube and transformer primary side function Rate windings in series；Output circuit includes secondary synchronous rectifier and output capacitance, the secondary side power winding coupling with the transformer It closes, output port of the energy that the transformer is discharged during primary side power switch tube shutdown in the output circuit A direct current is generated, load is supplied to；

The synchronous rectification inverse-excitation type DC-DC power control circuit generates double arteries and veins according to the feedback signal for receiving circuit of reversed excitation Periodic signal is rushed to realize the control to circuit of reversed excitation primary side power switch tube；

It is synchronous that the synchronous commutating control circuit generates secondary side by the pressure drop between detection secondary synchronous rectifier hourglass source electrode The control signal of rectifying tube.

2. synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：It is described Synchronous rectification inverse-excitation type DC-DC power control circuit can select internal dipulse electricity occurs according to circuit operating pattern Road bypasses the synchronous rectification inverse-excitation type DC-DC power control circuit is made to become conventional inverse-excitation type direct current-straight Galvanic electricity source mono pulse control circuit.

3. synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：It is described The DC input voitage of input circuit is the direct current of the DC voltage that DC power supply directly exports or the output of other conversion circuits Pressure or the DC input voitage are that the alternating voltage of power grid passes through the constant DC voltage of diode rectifier circuit output Or sinusoidal half-wave voltage.

4. synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：It is described Circuit of reversed excitation and synchronous commutating control circuit be specially：

Transformer primary side one terminates DC input voitage anode, the other end of transformer primary side and the drain electrode of primary side power switch tube Connection, the source electrode of primary side power switch tube connect DC input voitage cathode, one end of transformer secondary and synchronous rectification control electricity The drain electrode connection at the end VD, secondary synchronous rectifier on road, the grid of secondary synchronous rectifier and the VG of synchronous commutating control circuit End connection, the other end of transformer secondary are connect with one end of one end of capacitor Co, load, the other end and the load of capacitor Co The end GND of the other end, the source electrode of secondary synchronous rectifier and synchronous commutating control circuit connects.

5. synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：It is described Circuit of reversed excitation and synchronous commutating control circuit be specially：

The drain electrode of primary side power switch tube connects DC input voitage anode, and transformer primary side one terminates the source of primary side power switch tube Pole, another termination DC input voitage cathode of transformer primary side, one end of transformer secondary and synchronous commutating control circuit The drain electrode connection at the end VD, secondary synchronous rectifier, the grid of secondary synchronous rectifier and the end VG of synchronous commutating control circuit connect Connect, the other end of transformer secondary is connect with one end of one end of capacitor Co, load, the other end of capacitor Co and load it is another The end the GND connection at end, the source electrode of secondary synchronous rectifier and synchronous commutating control circuit.

6. synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：It is described The excitation current of transformer works in on-off state, continuous state or critical discontinuous state.