CN208158436U - A kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment - Google Patents
A kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment Download PDFInfo
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- CN208158436U CN208158436U CN201820569708.2U CN201820569708U CN208158436U CN 208158436 U CN208158436 U CN 208158436U CN 201820569708 U CN201820569708 U CN 201820569708U CN 208158436 U CN208158436 U CN 208158436U
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Abstract
The utility model discloses a kind of synchronous rectification inverse-excitation type DC-DC power conversion equipments, and the utility model includes circuit of reversed excitation and auxiliary switch；Circuit of reversed excitation includes an input port, an output circuit and a transformer；The input port receives DC input voitage, gives transformer-supplied, primary side power switch tube and the transformer primary side power windings in series；The energy that the transformer discharges during primary side power switch tube shutdown is generated a direct current in the output port, is supplied to load by the secondary side power winding coupled of output circuit and the transformer；The auxiliary switch is in parallel with the auxiliary winding of transformer.The utility model can realize the synchronous rectification inverse-excitation type DC-to-dc converter for without common risk, being compatible with discontinuous conduct mode, electric current critical discontinuous mode and continuous current mode using the secondary side synchronous rectification control technology of the prior art, and it is simple that the driving signal of auxiliary switch generates logic circuit.
Description
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 power switch tube, transformer loss, the loss of absorbing circuit and the loss of secondary side rectifier.Its
In, the loss of output end rectifier is one of dominant loss of inverse excitation type converter, in low-voltage, the output situation of high current
Under, the specific gravity that the loss of rectifying 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 QSRBody diode be connected afterflow, synchronous rectifier QSRDrain 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 QSRConducting.Synchronous rectifier QSRConducting 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 QSRControl signal Vg_SR when opening accidentally turn off, separately joined
Minimum turn-off time circuit 105 and with door 106 a minimum turn-off time is arranged, avoid synchronous rectifier QSRIt weighs after shut-off
It is new 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 Td2SRControl
It is low level, synchronous rectifier Q that signal Vg_SR is overturn from high levelSRShutdown, 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 QSRTurn-off time can control before secondary current zero crossing, therefore synchronous rectifier Q will not occurSRWith 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 QSRElectric 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 Td2SRJust turn off.It can be seen that in this section of section t3 to t5,
Primary side power switch tube Q1 and synchronous rectifier QSRIt 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 power switch tube is transferred to transformer secondary, then through being used to control secondary side synchronous rectification after certain logical process
Pipe.But due to transmission be high-frequency pulse signal, optocoupler will be using expensive high speed photo coupling, and magnetic cell price is more
Height, thus the method for this isolation transmission synchronous rectifier control signal in industry using relatively fewer.
Summary of the invention
In order to solve problem above, the utility model provides a kind of synchronous rectification inverse-excitation type DC-DC power conversion
Device.
A kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment, including：Circuit of reversed excitation and auxiliary switch；Flyback
Circuit includes an input circuit, an output circuit and a transformer；The input circuit includes primary side power switch
Pipe, the input circuit receive DC input voitage, give transformer-supplied, the primary side power switch tube and the transformer
Primary side power windings in series；The secondary side power winding coupled of output circuit and the transformer, by the transformer in the original
The energy that side power switch tube discharges during turning off generates a direct current in the output port of the output circuit, is supplied to negative
It carries；The auxiliary switch is in parallel with the auxiliary winding of transformer.
Preferably, the DC input voitage of the input circuit is the direct current that the DC power supplies such as battery directly export
Pressure or the DC voltage of other conversion circuits output, the DC input voitage are that the alternating voltage of power grid is whole by diode
The constant DC voltage or sinusoidal half-wave voltage of current circuit output.
Preferably, transformer primary side power winding one termination DC input voitage anode, transformer primary side power around
The other end of group is connect with the drain electrode of primary side power switch tube, and the source electrode of primary side power switch tube connects DC input voitage cathode；
The output circuit includes secondary synchronous rectifier and output capacitance Co, one end of the transformer secondary power winding with it is synchronous
The drain electrode connection at the end VD, secondary synchronous rectifier of rectifier control circuit, the grid of secondary synchronous rectifier and synchronous rectification control
The end VG of circuit processed connects, and the other end of transformer secondary power winding is connect with one end of one end of capacitor Co, load, capacitor
The other end of Co and the other end, the source electrode of secondary synchronous rectifier and the end GND of synchronous commutating control circuit of load connect；
The auxiliary switch is in parallel with the auxiliary winding of transformer.
Preferably, the source electrode of a termination primary side power switch tube of transformer primary side power winding, primary side power switch
The drain electrode of pipe connects DC input voitage anode, another termination DC input voitage cathode of transformer primary side power winding；It is described
Output circuit includes secondary synchronous rectifier and output capacitance Co, and one end of transformer secondary power winding and synchronous rectification control
The drain electrode connection at the end VD of circuit, secondary synchronous rectifier, the grid of secondary synchronous rectifier and synchronous commutating control circuit
The connection of the end VG, the other end of transformer secondary power winding are connect with one end of one end of capacitor Co, load, and capacitor Co's is another
It holds and is connect with the other end, the source electrode of secondary synchronous rectifier and the end GND of synchronous commutating control circuit of load；The auxiliary
It switchs in parallel with the auxiliary winding of transformer.
Preferably, the auxiliary switch is the semiconductor devices with two-way blocking-up ability.
Preferably, the auxiliary switch is diode and what metal oxide semiconductor field effect tube was constituted compound opens
It closes, the direction of diode is contrary with metal oxide semiconductor field effect tube body diode.
Preferably, the auxiliary switch is answering for the metal oxide semiconductor field effect tube composition of two differential concatenations
Combination switch.
Preferably, the time of the auxiliary switch conducting is fixed or by synchronous rectification inverse-excitation type DC-DC electricity
The control circuit of supply changeover device is adjusted according to the working condition of circuit.
Preferably, the excitation current of the transformer works in on-off state, continuous state or critical discontinuous state.
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, inevitably exists
Common problem.The utility model proposes synchronous rectification inverse-excitation type DC-DC power conversion equipment pass through in primary side power
Switching tube utilizes before opening and a period of time is connected with the auxiliary switch of transformer auxiliary winding parallel connection, by all windings of transformer
Voltage clamp is corresponded in zero level so that secondary synchronous rectifier both end voltage is equal to output voltage, to open in primary side power
It closes before pipe is opened and turns off secondary synchronous rectifier, eliminate primary side power switch tube and the common possibility of secondary synchronous rectifier
Property.And work as the work of synchronous rectification inverse-excitation type DC-to-dc converter under discontinuous conduct mode or electric current critical discontinuous mode, by
It can have been opened in primary side power switch tube in the control mode of the negative pressure of conventional detection secondary synchronous rectifier both end voltage
Secondary synchronous rectifier is turned off before logical in advance, therefore the device of the utility model is still applicable in.
Circuit structure used by the utility model, there is clear advantage compared with the existing technology；It only need to be auxiliary in transformer
The low pressure auxiliary switch of winding both ends parallel connection small-power, low cost is helped, i.e., is controlled using the secondary side synchronous rectification of the prior art
Technology realizes the synchronous rectification without common risk, compatible discontinuous conduct mode, electric current critical discontinuous mode and continuous current mode
Inverse-excitation type DC-to-dc converter, it is simple that the driving signal of auxiliary switch generates logic circuit.Further, auxiliary switch and its
The control circuit of drive signal generation circuit and conventional flyback converter is desirably integrated among same chip, is further dropped
Low installation cost.
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 synchronous rectification inverse-excitation type DC-to-dc converter the first specific embodiment schematic diagram of the utility model；
Fig. 5 shows the first specific embodiment work of the synchronous rectification inverse-excitation type DC-to-dc converter of the utility model
Specific waveform under continuous current mode；
Fig. 6 shows the first specific embodiment work of the synchronous rectification inverse-excitation type DC-to-dc converter of the utility model
Specific waveform under discontinuous conduct mode；
Fig. 7 shows the second specific embodiment signal of the synchronous rectification inverse-excitation type DC-to-dc converter of the utility model
Figure；
Fig. 8 shows the specific implementation of the auxiliary switch of the synchronous rectification inverse-excitation type DC-to-dc converter of the utility model
Example.
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.
Fig. 4 is the circuit of the first 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 and auxiliary switch Qa.
Wherein, the circuit of reversed excitation 200 includes：
Input circuit, including primary side power switch tube Q1 receive DC input voitage Vin and power to transformer T；It is described defeated
Enter circuit two input terminals be separately connected transformer T primary side power winding Wp Same Name of Ends and primary side power tube Q1 source
Pole, the anode of the termination DC input voitage Vin of the same name of the primary side power winding Wp of transformer T, the source electrode of primary side power tube Q1
The negative terminal of DC input voitage Vin is connect, the drain electrode of primary side power switch tube Q1 connects the different name of transformer T primary side power winding Wp
End, the grid of primary side power switch tube Q1 receive control signal Vg1；
Transformer T contains at least one primary side power winding Wp, a pair side power winding Ws and an auxiliary winding
Wa；
Output circuit, including secondary synchronous rectifier QSRWith 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 QSRDrain electrode, the secondary synchronous rectifier QSRSource electrode connect the cathode and synchronous commutating control circuit of output capacitance Co
The end GND, the secondary synchronous rectifier QSRGrid receive control signal Vg_SR.
The auxiliary switch Qa is in parallel with the auxiliary winding Wa of transformer T, a termination transformer T of the auxiliary switch Qa
Auxiliary winding Wa different name end, the Same Name of Ends of the auxiliary winding Wa of another termination transformer T of the auxiliary switch Qa is described
The control terminal of auxiliary switch Qa receives control signal Vga.
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 embodiment work of the synchronous rectification inverse-excitation type DC-to-dc converter of Fig. 5 the utility model
The synchronous commutating control circuit 100 of specific waveform and the prior art shown in FIG. 1 under continuous current mode：
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 QSRBody diode be conducted through secondary current Is so that
Secondary synchronous rectifier QSRThe 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 QSRBody 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 toSRGrid.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 processedSRConducting.In secondary synchronous rectifier QSRIt is secondary as secondary current Is electric current declines during conducting
Synchronous rectifier QSRThe 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 Vga of auxiliary switch Qa is high level, and control auxiliary switch Qa is connected, transformer T's
Auxiliary winding Wa is by Qa short circuit, since each winding of transformer T intercouples, the primary side power winding Wp of transformer T and secondary side function
Rate winding Ws both end voltage is also zero or is approximately zero, secondary synchronous rectifier QSRThe voltage Vds_SR at both ends is also accordingly equal to defeated
Voltage Vo out, thus be higher than reference voltage VTH2,102 output switching activity of comparator, make trigger 103 reset, trigger 103 it is defeated
Secondary synchronous rectifier Q is sent to through driving circuit 104 outSRGrid.Considering 100 internal logic of synchronous commutating control circuit
At the t4 moment after the delay Td2 that circuit generates, it is low electricity that secondary synchronous rectifier, which controls signal Vg_SR by high level overturning,
It is flat, control secondary synchronous rectifier QSRShutdown, meanwhile, the energy transfer stored in transformer T is to auxiliary winding Wa, and through assisting
Switch Qa constitutes circulation loop；
At the t5 moment, the control signal Vga of auxiliary switch Qa is low level by high level overturning, and auxiliary switch Qa is turned off,
The short-circuit effect of each winding of transformer T releases；In the same time or pass through after a bit of delay, primary side power switch tube Q1's
Grid signal is high level, primary side power switch tube Q1 conducting, in the auxiliary winding Wa and auxiliary of transformer T by low level overturning
The energy transfer of switch Qa circulation is to transformer primary side power winding Wp, so that primary current Ip generates certain initial value；In original
During side power switch tube Q1 is connected, transformer T is given at the primary side power both ends winding Wp that DC input voitage V1 is added in transformer T
Magnetizing inductance excitation, primary current Ip begins to ramp up.
By analyzing above as it can be seen that under continuous current mode, the utility model proposes synchronous rectification inverse-excitation type direct current-it is straight
Galvanic electricity supply changeover device has turned off secondary synchronous rectifier before primary side power switch tube is opened in advance, eliminates primary side power
A possibility that switching tube and common secondary synchronous rectifier.
Further, it can see by the work wave under the continuous current mode of Fig. 5, since the short circuit of auxiliary switch Qa is made
With the voltage Vds_ at the both ends primary side power switch tube Q1 of the synchronous rectification inverse-excitation type DC-to-dc converter of the utility model
Voltage value of the Q1 when Q1 opens moment is Vin, lower than the primary side power switch in conventional inverse-excitation type DC-to-dc converter
Voltage value of the voltage Vds_Q1 at the both ends pipe Q1 when Q1 opens moment is Vin+nVo, therefore the synchronous rectification of the utility model
Turn-on consumption of the primary side power switch tube Q1 of inverse-excitation type DC-to-dc converter under continuous current mode can reduce, this
It is also another advantage place of the utility model.
With reference to the first specific embodiment work of the synchronous rectification inverse-excitation type DC-to-dc converter of Fig. 6 the utility model
The synchronous commutating control circuit 100 of specific waveform and the prior art shown in FIG. 1 under discontinuous conduct mode：
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 QSRBody diode be conducted through secondary current Is so that
Secondary synchronous rectifier QSRThe 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 QSRBody 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 toSRGrid.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 QSRConducting；
In secondary synchronous rectifier QSRConducting, as secondary current Is electric current declines, secondary synchronous rectifier QSRBoth ends
Voltage Vds_SR rises.At the t3 moment, Vds_SR reaches reference voltage VTH2, and 102 output switching activity of comparator makes trigger 103
It resets, the output of trigger 103 sends secondary synchronous rectifier Q to through driving circuit 104SRGrid.Considering synchronous rectification
T4 moment after the delay Td2 that 100 internal logic circuit of control circuit generates, secondary synchronous rectifier QSRControl signal
Vg_SR is low level by high level overturning, controls secondary synchronous rectifier QSRShutdown, secondary synchronous rectifier QSRTwo pole of body
Pipe is conducted through secondary current Is；
At the t5 moment, secondary current Is drops to zero, magnetizing inductance and the both ends primary side power switch tube Q1 of transformer T
Equivalent capacity oscillation；
At the t6 moment, the control signal Vga of auxiliary switch Qa is high level, and control auxiliary switch Qa is connected, transformer T's
Auxiliary winding Wa is by Qa short circuit, since each winding of transformer T intercouples, the primary side power winding Wp of transformer T and secondary side function
Rate winding Ws both end voltage is also zero or is approximately zero, secondary synchronous rectifier QSRThe voltage Vds_SR at both ends is also accordingly equal to defeated
Voltage Vo out.Since the control signal Vg_SR in t4 moment secondary synchronous rectifier has overturn as low level, auxiliary is opened
The movement for closing Qa does not influence the state of Vg_SR；
At the t7 moment, the control signal Vga of auxiliary switch Qa is low level, each winding of transformer T by high level overturning
Short-circuit effect release, at the t7 moment or by after a bit of delay, the grid signal of primary side power switch Q1 is by low electricity
Flat overturning is high level, and DC input voitage V1 is added in excitation electricity of the primary side power both ends winding Wp to transformer T of transformer T
Feel excitation, primary current Ip starts from scratch rising.
By analyzing above as it can be seen that under discontinuous conduct mode, auxiliary switch Qa is to secondary synchronous rectifier QSRNormal work
Make no any influence, therefore also can choose the control signal of shielding auxiliary switch Qa under discontinuous conduct mode, so that auxiliary
Switch Qa is helped not work.
Fig. 7 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 and auxiliary switch Qa.
Wherein, the circuit of reversed excitation 200 includes：
Input circuit, including primary side power switch tube Q1 receive DC input voitage Vin and power to transformer T；It is described defeated
Two input terminals for entering circuit are separately connected the different of the drain electrode of primary side power switch tube Q1 and the primary side power winding Wp of transformer T
Name end, the drain electrode of primary side power switch tube Q1 connect the anode of DC input voitage Vin, and the source electrode of primary side power switch tube Q1 connects change
The Same Name of Ends of depressor T primary side power winding, the grid of primary side power switch tube Q1 receive control signal Vg1, the primary side of transformer T
The negative terminal of the different name termination DC input voitage Vin of power winding Wp；
Transformer T includes primary side power winding Wp, secondary side power winding Ws and auxiliary winding Wa；
Output circuit, including secondary synchronous rectifier QSRWith 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 QSRDrain electrode, the secondary synchronous rectifier QSRSource electrode connect the cathode and synchronous commutating control circuit of output capacitance Co
The end GND, the secondary synchronous rectifier QSRGrid receive control signal Vg_SR.
The auxiliary switch Qa is in parallel with the auxiliary winding Wa of transformer T, a termination transformer T of the auxiliary switch Qa
Auxiliary winding Wa different name end, the Same Name of Ends of the auxiliary winding Wa of another termination transformer T of the auxiliary switch Qa is described
The control terminal of auxiliary switch Qa receives control signal Vga.
Second specific embodiment of the synchronous rectification inverse-excitation type DC-to-dc converter of the utility model shown in Fig. 7 with
The difference of synchronous rectification inverse-excitation type first specific embodiment of DC-to-dc converter of the utility model shown in Fig. 4 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, here no longer
It repeats.
Further, professional and technical personnel should be known that the synchronous rectification inverse-excitation type DC-DC of the utility model turns
Parallel operation works in electric current critical discontinuous mode, and the turn off process of secondary synchronous rectifier and its work are in discontinuous conduct mode
Similar, auxiliary switch is also without influence, therefore no longer individually description.
Several specific embodiments of auxiliary switch Qa in the utility model with reference to shown in Fig. 8.Auxiliary switch Qa can be with
For individually with the semiconductor devices of two-way blocking-up ability, such as bipolar transistor shown in Fig. 8 (a), the bipolar transistor
Collector be connected to as the end A of auxiliary switch Qa transformer T primary side winding Wa different name end, the bipolar transistor
Emitter is connected to the Same Name of Ends of the primary side winding Wp of transformer T, the base of the bipolar transistor as the end B of auxiliary switch Qa
Pole receives control signal Vga as the control terminal C of auxiliary switch Qa.
Auxiliary switch Qa may be the combination switch for multiple semiconductor devices composition that Fig. 8 (b)~(c) is shown.With reference to
Fig. 8 (b), the auxiliary switch Qa are the combination switches that the MOSFET Qa1 and Qa2 reversely concatenated by two is constituted.Wherein, Qa1
Source electrode be connected to as the end A of auxiliary switch Qa transformer T auxiliary winding Wa different name end, drain electrode and the drain electrode of Qa2
Connection, the source electrode of Qa2 are connected to the Same Name of Ends of the auxiliary winding Wa of transformer T as the end B of auxiliary switch Qa, Qa1 and Qa2's
Grid, which is connected with each other, receives control signal Vga as the control terminal C of auxiliary switch Qa；With reference to Fig. 8 (c), the auxiliary switch Qa
A specific embodiment be the combination switch being made of a diode Db and a MOSFET Qb.Wherein, the anode of Db is made
For auxiliary switch Qa the end A be connected to transformer T auxiliary winding Wa different name end, the drain electrode of the cathode of Db and Qb connects, Qb
Source electrode be connected to as the end B of auxiliary switch Qa transformer T auxiliary winding Wa Same Name of Ends, the grid of Qb opens as auxiliary
The control terminal C for closing Qa receives control signal Vga.
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 describing certain schemes of the utility model in the form of certain specific rights requirements below, inventor is young
Carefully consider many claim forms of the various schemes of the utility model.Therefore, inventor increases after being retained in submission application
The right of accessory claim, to relate other schemes of the utility model in the form of these accessory claims.
Claims (9)
1. a kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment, it is characterised in that：Including：Circuit of reversed excitation and auxiliary
Switch；Circuit of reversed excitation includes an input circuit, an output circuit and a transformer；The input circuit includes primary side
Power switch tube, the input circuit receive DC input voitage, give transformer-supplied, primary side power switch tube and the change
Depressor primary side power windings in series；The secondary side power winding coupled of output circuit and the transformer, by the transformer in institute
It states the energy discharged during the shutdown of primary side power switch tube and generates a direct current in the output port of the output circuit, provide
To load；The auxiliary switch is in parallel with the auxiliary winding of transformer.
2. a kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：
The DC input voitage of the input circuit is the DC voltage or other conversion circuits that the DC power supplies such as battery directly export
The DC voltage of output, the DC input voitage are the alternating voltage of power grid by the constant of diode rectifier circuit output
DC voltage or sinusoidal half-wave voltage.
3. a kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：
One termination DC input voitage anode of transformer primary side power winding, the other end and original of transformer primary side power winding
The drain electrode of side power switch tube connects, and the source electrode of primary side power switch tube connects DC input voitage cathode；The output circuit packet
Include secondary synchronous rectifier and output capacitance Co, one end of the transformer secondary power winding 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
It connects, the other end of transformer secondary power winding is connect with one end of one end of capacitor Co, load, the other end of capacitor Co and negative
The end GND of the other end of load, the source electrode of secondary synchronous rectifier and synchronous commutating control circuit connects；The auxiliary switch with
The auxiliary winding of transformer is in parallel.
4. a kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：
The source electrode of one termination primary side power switch tube of transformer primary side power winding, the drain electrode of primary side power switch tube connect direct current input
Positive polarity, another termination DC input voitage cathode of transformer primary side power winding；Output circuit synchronizes whole including secondary side
Flow tube and output capacitance Co, one end and the end VD of synchronous commutating control circuit, secondary side of transformer secondary power winding are synchronous whole
The drain electrode of flow tube connects, and the grid of secondary synchronous rectifier and the end VG of synchronous commutating control circuit connect, transformer secondary function
The other end of rate winding is connect with one end of one end of capacitor Co, load, the other end of capacitor Co and the other end, the secondary side of load
The end the GND connection of the source electrode and synchronous commutating control circuit of synchronous rectifier；The auxiliary of the auxiliary switch and transformer around
Group is in parallel.
5. a kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：
The auxiliary switch is the semiconductor devices with two-way blocking-up ability.
6. a kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：
The auxiliary switch is the combination switch that diode and metal oxide semiconductor field effect tube are constituted, the direction of diode and gold
Belong to the contrary of oxide semiconductor field effect tube body diode.
7. a kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：
The auxiliary switch is the combination switch that the metal oxide semiconductor field effect tube of two differential concatenations is constituted.
8. a kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：
The time of the auxiliary switch conducting is control electricity fixed or by synchronous rectification inverse-excitation type DC-DC power conversion equipment
Road is adjusted according to the working condition of circuit.
9. a kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment according to claim 1, it is characterised in that：
The excitation current of the transformer works in on-off state, continuous state or critical discontinuous state.
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| CN201820569708.2U CN208158436U (en) | 2018-04-20 | 2018-04-20 | A kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment |
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| CN201820569708.2U CN208158436U (en) | 2018-04-20 | 2018-04-20 | A kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109640463A (en) * | 2019-02-25 | 2019-04-16 | 福州大学 | A kind of hybrid flyback LED drive circuit and quasi-resonance control method |
| CN111181425A (en) * | 2020-03-17 | 2020-05-19 | 美的集团股份有限公司 | Buck-boost driving circuit, air conditioner, method and computer-readable storage medium |
| CN111313709A (en) * | 2020-03-27 | 2020-06-19 | 杭州必易微电子有限公司 | Synchronous rectification control circuit, control method thereof and flyback isolated conversion circuit |
-
2018
- 2018-04-20 CN CN201820569708.2U patent/CN208158436U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109640463A (en) * | 2019-02-25 | 2019-04-16 | 福州大学 | A kind of hybrid flyback LED drive circuit and quasi-resonance control method |
| CN111181425A (en) * | 2020-03-17 | 2020-05-19 | 美的集团股份有限公司 | Buck-boost driving circuit, air conditioner, method and computer-readable storage medium |
| CN111313709A (en) * | 2020-03-27 | 2020-06-19 | 杭州必易微电子有限公司 | Synchronous rectification control circuit, control method thereof and flyback isolated conversion circuit |
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