CN205249052U - Synchronous Rectifier controlling means and switching power supply - Google Patents
Synchronous Rectifier controlling means and switching power supply Download PDFInfo
- Publication number
- CN205249052U CN205249052U CN201520920111.4U CN201520920111U CN205249052U CN 205249052 U CN205249052 U CN 205249052U CN 201520920111 U CN201520920111 U CN 201520920111U CN 205249052 U CN205249052 U CN 205249052U
- Authority
- CN
- China
- Prior art keywords
- circuit
- resistance
- control circuit
- power supply
- underloading
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Abstract
The utility model provides a synchronous Rectifier controlling means, includes underloading control circuit, underloading control circuit includes signal transmission circuit and drive control circuit, the signal transmission circuit for with former limit PWM control chip's feedback foot COM's feedback signal, transmit vice limit to from former limit through the opto -coupler, offer drive and control circuit, drive and control circuit for the former limit PWM control chip's that the receipt is come by opto -coupler transmission feedback foot COM's feedback signal, when the load is light, control chip's feedback foot COM level is low, and then drive and control circuit closes this winding self -driven synchronous rectification circuit, so that the synchronous Rectifier MOS plumber does at the diode rectification state of personally experiencing sth. Part of the body, in order to realize empty load or the little purpose of underloading consumption, when the load was heavy, control chip's feedback foot COM level was high, then this winding self -driven of drive and control circuit noninterference synchronous rectification circuit's work to realize fully loadedly or heavily loaded efficient mesh.
Description
Technical field
The utility model relates to a kind of Switching Power Supply, particularly the synchronous commutation control device of Switching Power Supply and the Switching Power Supply based on this synchronous commutation control device.
Background technology
Along with the fast development of semiconductor devices and super large-scale integration, to large electric current, low-voltage, the demand of low cost isolating switch power also significantly increases thereupon. Forward voltage drop only has the Schottky diode rectification of 0.3V-0.7V, and large conduction loss becomes the bottleneck of Switching Power Supply miniaturization. In order to improve the efficiency of low-voltage, high-current switch power supply, output rectification has all adopted synchronous rectification, in prior art, is all generally to have adopted three kinds of type of drive, Transformer Winding voltage self-driven type, isolation drive type and current drive-type
Circuit is as shown in Figure 1 Transformer Winding self-driven type, Transformer Winding self-driven type is because driving voltage is the auxiliary winding from transformer, and circuit is simple, space is little, and cost is low, so in the modular power source application of high power density, winding self-driven type is widely used. But winding self-driven type circuit due in output loading be idling carry or underloaded situation under, as shown in Figure 2, output current can zero passage, is namely to there will be reversing the current in each switch periods for its waveform. Will cause like this open circuit loss of Switching Power Supply to strengthen or light-load efficiency reduction.
Its open circuit loss become large principle into: in the application of flyback or flyback class power topology, in zero load or underloading situation, the transformer B value amplitude of oscillation changes to first and third quadrant by first quartile, and Δ B becomes and causes greatly the core loss of transformation to become greatly. Owing to there being synchronous rectifier to occur reversing the current, so increased the turn-off power loss of synchronous rectification.
In like manner in the power topology application of normal shock or normal shock class, opening up transformation due to the power of normal shock class was exactly to be operated in first and third quadrant originally, but its output energy storage inductor B value should be to be only operated in first quartile, in there is negative current in synchronous rectification switch, allow too the B value work of outputting inductance to first and third quadrant, increase equally the core loss of energy storage inductor and the turn-off power loss of synchronous rectifier.
Therefore the large and light-load efficiency of open circuit loss is low is the shortcoming of winding self-device synchronous rectification maximum;
And the circuit of synchronous rectification shown in employing Fig. 3 is isolation drive type circuit of synchronous rectification, its principle is for adopting isolation drive transformer, from the former limit transmission of control signals of converter to secondary, be used for the synchronous rectification rectification of driving transducer secondary, this drive circuit can overcome the large shortcoming of open circuit loss of Transformer Winding self-powered type, but the new problem of bringing is because needs increase isolation drive transformer and interlock circuit, isolating transformer is because volume ratio is larger, cost is higher, is difficult to application in the modular power source of high power density.
And the synchronous rectification driving circuit shown in employing Fig. 4 is current drive-type synchronous rectification, its principle is mainly in the secondary loop of Switching Power Supply, connect sampling resistor or current transformer, gather the secondary current signal of Switching Power Supply, after overvoltage and power amplification, be used for driving synchronous rectifier, if occur the situation of current over-zero in the time of zero load or underloading, because the voltage direction of drive waveforms will change, be formed with forward current after oversampling circuit arranges time, there is drive waveforms, when current waveform to zero, driving voltage waveform also drops to zero, synchronous rectification drives and will be turned off. create conditions so just to output current zero passage, so the circuit of synchronous rectification of current drive-type there will not be Switching Power Supply secondary current zero passage, namely there will not be the self-driven no-load power consumption of synchronous rectification winding to become the problem of large and light-load efficiency step-down. current drive-type synchronous rectification has very many circuit form and patent according to the method for the method of the method for current sample, amplification, control. although it is large that current mode synchronous rectification has overcome open circuit loss, the problem that light-load efficiency is low, but be not suitable for equally the modular power source of high power density, because the transformer that current drive-type synchronous rectification adopts and resistance are to be all connected on the main loop of power circuit of Switching Power Supply secondary, the output current of high power density power supply is all generally very large, can cause very large loss at full load, reduce the full load efficiency of high power modular power source. if the power supply of 3.3V output 100W is when the fully loaded work, output current is to 30A, if adopt resistance can bring the loss about nearly 5W to 5m Ω, decrease in efficiency exceedes 4%. so adopt this drive scheme to reduce full load efficiency when light-load efficiency promotes, lose more than gain. and the volume the causing change that adopts resistance or current transformer is greatly also that high power density power supply institute is unacceptable.
The merits and demerits of three kinds of synchronous rectification driving circuits in sum as shown in Table 1.
Table one
The ideal synchronisation rectification of high power density modular power source is: zero load or underloading power consumption is little, volume/cost is little, full load efficiency is high.
In isolation type switch power, in order to realize the stable of switch power source output voltage, control mode is mainly PWM and controls, be again pulse-width adjustment control mode, its principle is, the ratio that accounts for PRT by the by-pass cock pulse high-voltage time is carried out regulation output voltage, and this ratio is defined as dutycycle in Switching Power Supply. Its concrete mode is, in the time that output voltage raises, negative-feedback circuit will detect and transmit the feedback pin of this signal to pwm chip, the level of feedback pin changes, pwm chip can be according to the pulse drive signal of the level output duty ratio corresponding of this variation, allow the output voltage of Switching Power Supply reduce, to realize the object of regulated output voltage. If the output voltage of Switching Power Supply is while declining, otherwise above-mentioned logical process is.
In the time that the load of Switching Power Supply changes, output voltage can change, and the feedback pin level of pwm chip also can change.
Utility model content
An object of the present utility model is, provides a kind of and can realize zero load or underloading power consumption is little, volume/cost is little, full load efficiency is high synchronous commutation control device.
Another object of the present utility model is, provides a kind of and can realize zero load or underloading power consumption is little, volume/cost is little, full load efficiency is high Switching Power Supply.
In order to realize foregoing invention object, the utility model provides a kind of synchronous commutation control device, for the devices of Switching Power Supply is carried out to synchronous rectification control, comprise winding self-device synchronous rectification circuit, described synchronous commutation control device also comprises underloading control circuit, described underloading control circuit comprises signal circuit and Drive and Control Circuit, described signal circuit, its input is connected to the feedback pin COM of pwm chip, output is connected to Drive and Control Circuit input, in order to by the feedback signal of the feedback pin COM of former limit pwm chip, be transferred to secondary by optocoupler from former limit, offer Drive and Control Circuit, described Drive and Control Circuit, its output is connected to the input of winding self-device synchronous rectification circuit, in order to receive the feedback signal of being transmitted the feedback pin COM of the former limit pwm chip coming by optocoupler, and according to the height of feedback signal level, to winding self-device synchronous rectification circuit output control signal, taking in feedback signal during as low level, when the output loading that characterizes Switching Power Supply is underloading or zero load, close this winding self-device synchronous rectification circuit, make devices be operated in body diode rectification state, in the time that feedback signal is high level, when the output loading that characterizes Switching Power Supply is heavily loaded, do not interfere the work of this winding self-device synchronous rectification circuit, in order to realize the high object of Switching Power Supply heavy duty efficiency.
Preferably, described signal circuit, comprise resistance R 31, resistance R 32, resistance R 33, error amplifier U31, optocoupler U32, its concrete annexation is that one end of resistance R 31 is connected to pwm chip feedback pin COM, is the input of signal circuit; One end of other end contact resistance R32 of resistance R 31 and the control pin of error amplifier U31, the other end of resistance R 32 is connected to the former limit of Switching Power Supply with reference to ground; One end of resistance R 33 is connected to the former limit feeder ear VCC of Switching Power Supply, the other end of resistance R 33 is connected to the former limit anode of optocoupler U32, the former limit negative electrode of optocoupler U32 is connected to the negative electrode of error amplifier U31, and the anodic bonding of error amplifier U31 arrives the former limit of Switching Power Supply with reference to ground.
Preferably, described error amplifier U32 is TL431.
Preferably, described Drive and Control Circuit, comprises resistance R 41, resistance R 42, resistance R 43, triode Q41 and diode D41, and its concrete annexation is that one end of this resistance R 41 is connected to the output of Switching Power Supply secondary and rectifies VO; One end of the other end contact resistance R42 of resistance R 41, the other end of resistance R 42 is connected to one end of R43 and is connected to the base stage of triode Q41; The other end of resistance R 43 is connected to Switching Power Supply secondary with reference to ground and is connected to the emitter stage of triode Q41, and the negative electrode of diode D41 is connected to the colelctor electrode of triode Q41, and the anode of diode D41 is drawn the output as underloading control circuit.
Preferably, described winding self-device synchronous rectification circuit, comprises and drives winding N21, capacitor C 21 and resistance R 21, the Same Name of Ends of this driving winding N21 is connected to one end of capacitor C 21, drives the different name end of winding N21 to be connected to the drain electrode of devices; The other end of capacitor C 21 is connected to the grid of devices; One end of resistance R 21 is connected to the grid of synchronous rectifier, and the other end is connected to the source electrode of devices.
The utility model also provides a kind of Switching Power Supply, comprise circuit for power conversion with devices and above-mentioned synchronous commutation control device, the underloading control circuit of described synchronous commutation control device is connected in parallel between the grid and source electrode of devices, the grid that is devices is connected with the colelctor electrode of triode Q41 through the diode D41 of underloading control circuit, the source electrode of devices is connected with the emitter stage of the triode Q41 of underloading control circuit, taking in the feedback signal of signal circuit during as low level, close this winding self-device synchronous rectification circuit by underloading control circuit, make devices be operated in body diode rectification state, in the time that the feedback signal of signal circuit is high level, underloading control circuit is not interfered the work of this winding self-device synchronous rectification circuit.
Synchronous rectification control method of the present utility model has the following advantages.
1, circuit is simple, volume is little.
2, no-load power consumption is little.
3, full load efficiency is high.
Brief description of the drawings
Fig. 1 is the schematic diagram of the winding self-device synchronous rectification circuit of prior art;
Fig. 2 is driving voltage and the current waveform figure of the current mode circuit of synchronous rectification of prior art;
Fig. 3 is the schematic diagram of the isolation drive type circuit of synchronous rectification of prior art;
Fig. 4 is the schematic diagram of the current mode circuit of synchronous rectification of prior art;
Fig. 5 is the schematic diagram of the utility model synchronous rectification Drive and Control Circuit;
Fig. 6 is the circuit theory diagrams of the synchronous commutation control device of the utility model case study on implementation one;
Fig. 7 is that the synchronous commutation control device of the utility model case study on implementation one is applied in the circuit theory diagrams in the Switching Power Supply of flyback topology;
Fig. 8 is that the synchronous commutation control device of the utility model case study on implementation one is applied in the circuit theory diagrams in push-pull topology Switching Power Supply.
Detailed description of the invention
The improvement of having done with respect to prior art in order to understand better the utility model, before two kinds of detailed description of the invention of the present utility model are elaborated, first to the utility model, design is illustrated by reference to the accompanying drawings.
As shown in Figure 5, a kind of synchronous rectification control method, for the devices of Switching Power Supply is carried out to synchronous rectification control, the method is on the control basis of winding self-device synchronous rectification circuit, increase underloading control step, described underloading control step, at the feedback pin COM of the former limit of Switching Power Supply control chip, produce a level changing with output loading, signal circuit is to this variation level processing, be transferred to the Drive and Control Circuit of Switching Power Supply secondary, Drive and Control Circuit is to winding self-device synchronous rectification circuit output control signal, in the time that load is light, the feedback pin COM level of control chip is low, Drive and Control Circuit is closed this winding self-device synchronous rectification circuit, so that devices is operated in body diode rectification state, to realize zero load or the little object of underloading power consumption, in the time that load is heavy, the feedback pin COM level of control chip is high, and Drive and Control Circuit is not interfered the work of this winding self-device synchronous rectification circuit, to realize fully loaded or the high object of heavily loaded efficiency.
Simultaneously, at the pwm chip feedback foot level on the former limit of Switching Power Supply, while changing with the size of Switching Power Supply output load current, a control logic of utilizing this variable signal to produce, and control logic is transferred to secondary from the former limit of Switching Power Supply, for controlling the duty of synchronous rectification.
Thinking accordingly, the utility model provides a kind of synchronous commutation control device, for circuit for power conversion 1, comprise winding self-device synchronous rectification circuit 2 and underloading control circuit, this underloading control circuit comprises signal circuit 3 and Drive and Control Circuit 4, and the input of described signal circuit 3 is connected to the feedback pin COM of pwm chip, and output is connected to the input of Drive and Control Circuit 4, the level of the COM pin changing with output loading in order to conversion, transmission, offers Drive and Control Circuit 4; The output of described Drive and Control Circuit 4 is connected to the input of winding self-device synchronous rectification circuit 2, and according to the level height situation of pwm chip feedback pin COM, export control signal to winding self-device synchronous rectification circuit 2, taking at power source loads during as zero load, pwm chip feedback pin COM level is low, close this winding self-device synchronous rectification circuit 2, so that devices is operated in body diode rectification state, to realize zero load or the little object of underloading power consumption. In the time that load is heavy, the feedback pin COM level of control chip is high, and Drive and Control Circuit is not interfered the work of this winding self-device synchronous rectification circuit, to realize fully loaded or the high object of heavily loaded efficiency.
Under normal circumstances, the output of Switching Power Supply in zero load or underloading described in the voltage of feedback pin COM of pwm chip low, in heavily loaded or fully loaded situation, the feedback pin COM voltage of described pwm chip is high.
The synchronous rectifier of described winding self-device synchronous rectification circuit 2 can be the metal-oxide-semiconductor of one or more parallel connections.
The logic state that described Drive and Control Circuit 4 is exported according to signal circuit 3, form a control signal, when the output of Switching Power Supply is in zero load or underloading, the feedback pin COM level of pwm chip is low, signal circuit 3 is exported a high logic level to Drive and Control Circuit 4, Drive and Control Circuit 4 is exported a control signal, the driving of winding self-device synchronous rectification circuit 2 is closed, devices is operated in body diode rectification state, the rectification circuit that is equal to described circuit for power conversion 1 adopts diode rectification, the secondary current of power inverter can zero passage, so zero load or underloading loss are little. when auxiliary power circuit 3 level are when high, control signal will not interfered winding self-device synchronous rectification circuit, and metal-oxide-semiconductor normally rectification work, keeps fully loaded or the high feature of heavily loaded efficiency.
The sample variation level of feedback pin COM of pwm chip of described signal circuit 3, its concrete method is, by the method sampling COM pin voltage of two series resistance dividing potential drops, the same reference voltage of this voltage compares, and during lower than reference voltage, signal circuit 3 is exported a high logic level. Voltage after COM dividing potential drop higher than reference voltage after time signal circuit 3 export a low logic.
Described signal circuit 3 is transferred to secondary by logic level from former limit, and transmission path adopts optocoupler to realize.
The comparator IC of described signal circuit 3 is TL431.
Above-mentioned circuit for power conversion 1 can be various isolated topology, as flyback, normal shock, recommend, the topology of half-bridge, full-bridge etc. and conversion thereof.
The method that Drive and Control Circuit 4 is closed winding self-device synchronous rectification circuit 2 is, adopt a gate-controlled switch to be connected in parallel between the grid and source electrode of devices, when the voltage of auxiliary power circuit 3 switch conduction when being low level, level between devices grid and source electrode is pulled down to low level state always, synchronous rectification MOS is without driving, always in off state.
Above-mentioned switch can be the controlled crystal switches such as triode, metal-oxide-semiconductor, optocoupler, controllable silicon.
The tandem drive electric capacity of winding self-device synchronous rectification circuit 2, is that a capacitor's capacity is difficult for excessive electric capacity, is mainly the On current in order to limit above-mentioned switch, prevents that switch member is by overcurrent damage.
Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail.
Embodiment mono-
Fig. 6 shows the synchronous rectification Drive and Control Circuit of the utility model embodiment mono-, and a kind of synchronous commutating control circuit comprises winding self-device synchronous rectification circuit 2, signal circuit 3 and Drive and Control Circuit 4.
Wherein, Drive and Control Circuit 4 receives the control logic level of signal circuit 3.
At the feedback pin COM of the former limit of Switching Power Supply control chip, produce one with output loading variation level, signal circuit to this variation level processing, be transferred to the Drive and Control Circuit of Switching Power Supply secondary, Drive and Control Circuit is to winding self-device synchronous rectification circuit output control signal, in the time that load is light, the feedback pin COM level of control chip is low, Drive and Control Circuit is closed this winding self-device synchronous rectification circuit, so that devices is operated in body diode rectification state; To realize zero load or the little object of underloading power consumption, in the time that load is heavy, the feedback pin COM level of control chip is high, and Drive and Control Circuit is not interfered the work of this winding self-device synchronous rectification circuit, to realize fully loaded or the high object of heavily loaded efficiency.
After winding self-device synchronous rectification circuit 2 is closed by the control signal of Drive and Control Circuit 4, devices is operated in body diode rectification state, Switching Power Supply secondary is operated in diode rectification state in underload or when unloaded, electric current can zero passage, so zero load or underloading loss are little.
Preferably, circuit for power conversion 1, is flyback topological structure. It comprises the first switching tube Q11, the first transformer T1, winding self-device synchronous rectification circuit 2, the first output filter capacitor C11, the first input filter capacitor C12. The annexation of flyback topological structure and operation principle are prior art, all very many in books and existing document, are not described in detail at this.
Preferably, winding self-device synchronous rectification circuit 2, is a part for circuit for power conversion 1, comprises the first driving winding N21, and first drives capacitor C 21, the first pull down resistor R21, the first devices Q21. Drive the Same Name of Ends of winding N21 to be connected to one end of the first driving capacitor C 21, drive the different name end of winding N21 to be connected to the drain electrode of the first devices Q21. First drives the other end of capacitor C 21 to be connected to the grid of the first devices Q21. One end of the first pull down resistor R21 is connected to the grid of the first synchronous rectifier Q21, and the other end is connected to the source electrode of the first devices Q21. The first devices Q21 drain electrode is connected to the different name end of the first power winding N11 of circuit for power conversion 1.
Preferably, signal circuit 3, comprises the first sampling resistor R31, the second sampling resistor R32, the first current-limiting resistance R33, the first error amplifier U31, the first optocoupler U32. One end of resistance R 31 is connected to pwm chip feedback pin COM, is the input of signal circuit. The other end of the first sampling resistor R31 is connected to the other end of the second sampling resistor R32 and the control pin of the first error amplifier U31. The other end of the second sampling resistor R32 is connected to the former limit of Switching Power Supply with reference to ground. One end of the first current-limiting resistance R33 is connected to the former limit feeder ear VCC of Switching Power Supply, the other end of the first current-limiting resistance R33 is connected to the former limit anode of the first optocoupler U32, the former limit negative electrode of the first optocoupler U32 is connected to the negative electrode of the first error amplifier U31, and the anodic bonding of the first error amplifier U31 arrives the former limit of Switching Power Supply with reference to ground.
Preferably, the first error amplifier U31 is TL431.
Preferably, described Drive and Control Circuit 4, comprises resistance R 41, resistance R 42, resistance R 43, triode Q41 and diode D41. One end of this resistance R 41 is connected to the output of switch Switching Power Supply secondary and rectifies VO; One end of the other end contact resistance R41 of resistance R 41, the other end of resistance R 42 is connected to one end of R43 and is connected to the base stage of triode Q41; The other end of resistance R 43 is connected to Switching Power Supply secondary with reference to ground and is connected to the emitter stage of triode Q41, the negative electrode of diode D41 is connected to the colelctor electrode of triode Q41, the anodic bonding of diode is drawn the output as underloading control circuit to the anode of diode D41, in order to be connected to the input control point G1 of described winding self-device synchronous rectification circuit.
Preferably, described winding self-device synchronous rectification circuit 2, comprises and drives winding N21, capacitor C 21 and resistance R 21, the Same Name of Ends of this driving winding N21 is connected to one end of capacitor C 21, drives the different name end of winding N21 to be connected to the drain electrode of devices; The other end of capacitor C 21 is connected to the grid of devices; One end of resistance R 21 is connected to the grid of synchronous rectifier, and the other end is connected to the source electrode of devices.
Preferably, Drive and Control Circuit 4, comprises the first sampling resistor R41, the second sampling resistor R42, the 3rd sampling resistor R43, the first switch triode Q41 and the first diode D41.
Preferably, one end of the first sampling resistor R41 is connected to the output VO of switch, and the other end of the first sampling resistor R41 is connected to one end of the second sampling resistor R42, and is connected to the colelctor electrode of the first optocoupler U32 secondary. One end of one termination the 3rd sampling resistor of the second sampling resistor, and be connected to the base stage of the first triode Q41. Another termination Switching Power Supply secondary of the 3rd sampling resistor is with reference to ground. The emitter stage of the first triode Q41 is also connected to the reference ground of Switching Power Supply secondary. The colelctor electrode of the first triode Q41 is connected to the negative electrode of the first diode D41. The anode of the first diode D41 is drawn the output as underloading control circuit, in order to be connected to the input control point G1 of described winding self-device synchronous rectification circuit 2.
As shown in Figure 7, for the synchronous commutation control device of the utility model case study on implementation one is applied in the circuit theory diagrams in flyback topology Switching Power Supply, a kind of Switching Power Supply, comprise circuit for power conversion 1 and synchronous commutation control device with devices, wherein, synchronous commutation control device comprises underloading control circuit, underloading control circuit comprises signal circuit 3 and Drive and Control Circuit 4, the underloading control circuit of synchronous commutation control device is connected in parallel between the grid and source electrode of devices, the grid that is devices is connected with the colelctor electrode of triode Q41 through the diode D41 of underloading control circuit, the source electrode of devices is connected with the emitter stage of the triode Q41 of underloading control circuit, taking in the feedback signal of signal circuit during as low level, close this winding self-device synchronous rectification circuit by underloading control circuit, make devices be operated in body diode rectification state, in the time that the feedback signal of signal circuit is high level, underloading control circuit is not interfered the work of this winding self-device synchronous rectification circuit.
As shown in Figure 8, for the synchronous commutation control device of the utility model case study on implementation one is applied in the circuit theory diagrams in push-pull topology Switching Power Supply, be with the difference of the synchronous commutation control device of the single channel output shown in Fig. 7, applicable circuit topology is different, and the quantity of the devices that output is controlled is also different. Synchronous commutation control device shown in Fig. 7 is applied to flyback topology, and its output is used for controlling single devices. Synchronous commutation control device shown in Fig. 8 is applied to push-pull topology, its output is used for controlling two devices, it is synchronous commutation control device is controlled respectively devices Q21, Q22 gate terminal via diode D41, D42, the concrete annexation of this part is that the colelctor electrode of triode Q41 is connected with the negative electrode of diode D41, D42 respectively, and the anode of diode D41, D42 connects respectively the grid of devices Q21, Q22. Synchronous commutation control device is for controlling the operation principle of two devices, basic identical with the operation principle of the synchronous commutation control device of the single devices of above-mentioned control, do not repeat them here. On this basis, the utility model those skilled in the art can also, according to circuit design needs, change, combine above-mentioned embodiment.
Claims (6)
1. a synchronous commutation control device, for the devices of Switching Power Supply is carried out to synchronous rectification control,Comprise winding self-device synchronous rectification circuit, it is characterized in that: described synchronous commutation control device also comprises underloading control circuit,Described underloading control circuit comprises signal circuit and Drive and Control Circuit,
Described signal circuit, its input is connected to the feedback pin COM of pwm chip, and output is connected to and drives controlCircuit input end processed, in order to by the feedback signal of the feedback pin COM of former limit pwm chip, passes from former limit by optocouplerBe passed to secondary, offer Drive and Control Circuit,
Described Drive and Control Circuit, its output is connected to the input of winding self-device synchronous rectification circuit, in order to receive by optocouplerThe feedback signal of the feedback pin COM of the former limit pwm chip that transmission comes, and according to the height of feedback signal level, toWinding self-device synchronous rectification circuit output control signal, during as low level, to characterize the defeated of Switching Power Supply in feedback signalGo out load and be underloading or when unloaded, close this winding self-device synchronous rectification circuit, make devices be operated in bodyDiode rectification state; In the time that feedback signal is high level, when the output loading that characterizes Switching Power Supply is heavily loaded, dryRelate to the work of this winding self-device synchronous rectification circuit, in order to realize the high object of Switching Power Supply heavy duty efficiency.
2. synchronous commutation control device according to claim 1, is characterized in that: described signal circuit, bagDraw together resistance R 31, resistance R 32, resistance R 33, error amplifier U31, optocoupler U32, its concrete annexation is, resistanceOne end of R31 is connected to pwm chip feedback pin COM, is the input of signal circuit; Resistance R 31 anotherOne end of one end contact resistance R32 and the control pin of error amplifier U31, the other end of resistance R 32 is connected to Switching Power SupplyFormer limit with reference to ground; One end of resistance R 33 is connected to the former limit feeder ear VCC of Switching Power Supply, and the other end of resistance R 33 connectsThe former limit anode of receiving optocoupler U32, the former limit negative electrode of optocoupler U32 is connected to the negative electrode of error amplifier U31, and error is amplifiedThe anodic bonding of device U31 arrives the former limit of Switching Power Supply with reference to ground.
3. synchronous commutation control device according to claim 2, is characterized in that: described error amplifier U32 isTL431。
4. synchronous commutation control device according to claim 1, is characterized in that: described Drive and Control Circuit, bagDraw together resistance R 41, resistance R 42, resistance R 43, triode Q41 and diode D41, its concrete annexation is, this resistanceOne end of R41 is connected to the output of Switching Power Supply secondary and rectifies VO; One end of the other end contact resistance R42 of resistance R 41, electricityThe other end of resistance R42 is connected to one end of R43 and is connected to the base stage of triode Q41; The other end of resistance R 43 is connected toSwitching Power Supply secondary is with reference to ground and be connected to the emitter stage of triode Q41, and the negative electrode of diode D41 is connected to triode Q41Colelctor electrode, the anode of diode D41 is drawn the output as underloading control circuit.
5. according to the synchronous commutation control device described in any one in claim 1 to 4, it is characterized in that: described windingSelf-device synchronous rectification circuit, comprises and drives winding N21, capacitor C 21 and resistance R 21, this driving winding N21's is of the same nameEnd is connected to one end of capacitor C 21, drives the different name end of winding N21 to be connected to the drain electrode of devices; Electric capacityThe other end of C21 is connected to the grid of devices; One end of resistance R 21 is connected to the grid of synchronous rectifier,The other end is connected to the source electrode of devices.
6. a Switching Power Supply, comprises in circuit for power conversion with devices and claim 1 to 5 arbitrarySynchronous commutation control device described in, is characterized in that: the underloading control circuit of described synchronous commutation control device is connected in parallel onBetween the grid and source electrode of devices, the grid of devices is through the diode of underloading control circuitD41 is connected with the colelctor electrode of triode Q41, the triode Q41 of the source electrode of devices and underloading control circuitEmitter stage connect, during as low level, to close this winding by underloading control circuit in the feedback signal of signal circuitSelf-device synchronous rectification circuit, makes devices be operated in body diode rectification state; Anti-at signal circuitWhen feedback signal is high level, underloading control circuit is not interfered the work of this winding self-device synchronous rectification circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520920111.4U CN205249052U (en) | 2015-11-18 | 2015-11-18 | Synchronous Rectifier controlling means and switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520920111.4U CN205249052U (en) | 2015-11-18 | 2015-11-18 | Synchronous Rectifier controlling means and switching power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205249052U true CN205249052U (en) | 2016-05-18 |
Family
ID=55948121
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520920111.4U Active CN205249052U (en) | 2015-11-18 | 2015-11-18 | Synchronous Rectifier controlling means and switching power supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205249052U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105281578A (en) * | 2015-11-18 | 2016-01-27 | 广州金升阳科技有限公司 | Synchronous rectifying control method and control device and switching power supply |
| CN108667306A (en) * | 2018-05-17 | 2018-10-16 | 中国科学院电工研究所 | A kind of circuit of synchronous rectification and method |
| CN108809122A (en) * | 2018-06-04 | 2018-11-13 | 广东美的制冷设备有限公司 | Rectification control method, air conditioner and computer readable storage medium |
| CN111404402A (en) * | 2020-03-02 | 2020-07-10 | 深圳固邦科技有限公司 | Self-adaptive output no-load control circuit and voltage conversion circuit |
| CN111865090A (en) * | 2020-07-16 | 2020-10-30 | 北京卫星制造厂有限公司 | Secondary synchronous rectification control circuit and method based on primary current sampling |
-
2015
- 2015-11-18 CN CN201520920111.4U patent/CN205249052U/en active Active
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105281578A (en) * | 2015-11-18 | 2016-01-27 | 广州金升阳科技有限公司 | Synchronous rectifying control method and control device and switching power supply |
| CN105281578B (en) * | 2015-11-18 | 2018-06-29 | 广州金升阳科技有限公司 | Synchronous commutation control device and Switching Power Supply |
| CN108667306A (en) * | 2018-05-17 | 2018-10-16 | 中国科学院电工研究所 | A kind of circuit of synchronous rectification and method |
| CN108809122A (en) * | 2018-06-04 | 2018-11-13 | 广东美的制冷设备有限公司 | Rectification control method, air conditioner and computer readable storage medium |
| CN111404402A (en) * | 2020-03-02 | 2020-07-10 | 深圳固邦科技有限公司 | Self-adaptive output no-load control circuit and voltage conversion circuit |
| CN111404402B (en) * | 2020-03-02 | 2023-03-14 | 深圳固邦科技有限公司 | Self-adaptive output no-load control circuit and voltage conversion circuit |
| CN111865090A (en) * | 2020-07-16 | 2020-10-30 | 北京卫星制造厂有限公司 | Secondary synchronous rectification control circuit and method based on primary current sampling |
| CN111865090B (en) * | 2020-07-16 | 2022-01-04 | 北京卫星制造厂有限公司 | Secondary synchronous rectification control circuit and method based on primary current sampling |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105006974B (en) | synchronous rectification control method, control device and switching power supply | |
| US9923476B2 (en) | Switching power supply and method for controlling switching power supply | |
| CN205249052U (en) | Synchronous Rectifier controlling means and switching power supply | |
| CN105281578A (en) | Synchronous rectifying control method and control device and switching power supply | |
| US9252677B2 (en) | Quasi resonant push-pull converter and control method thereof | |
| CN104022640A (en) | DC-DC converter of single inductor output driver based on resonance and method | |
| TWI672898B (en) | Bidirectional DC-DC converter | |
| CN110719035B (en) | Topological structure of single-stage DAB-LLC hybrid bidirectional DC-DC converter | |
| CN100438286C (en) | Dual-tube dual-forward-excitation boosting type single-stage power factor correction circuit | |
| CN106655775B (en) | Two-port input ZVT high-gain Boost converter with soft switch | |
| CN209982336U (en) | Three-level Boost converter and photovoltaic system | |
| CN109494989B (en) | Low-power voltage compensation combined DC/DC converter circuit and working method thereof | |
| CN107404228A (en) | A kind of novel wide scope input power translation circuit | |
| CN108448902A (en) | A kind of synchronous rectification inverse-excitation type DC-DC power conversion equipment and control method | |
| CN104218800A (en) | High-reduction-voltage non-isolating-type direct current (DC)/DC converter | |
| CN103647448B (en) | Integrated step-down-flyback type high power factor constant current circuit and device | |
| CN109450260A (en) | A kind of capacitance series formula crisscross parallel circuit of reversed excitation | |
| CN203617902U (en) | Integrated buck-flyback type high power factor constant current circuit and device | |
| CN108599346B (en) | Three-level electric automobile charging circuit | |
| CN104135154A (en) | Isolated four-element resonance circuit and control method | |
| CN103023315A (en) | Boost circuit | |
| CN204068701U (en) | A kind of non-isolation type high step-down ratio DC/DC converter | |
| CN207664872U (en) | A kind of novel wide scope input power translation circuit | |
| CN107222109B (en) | A kind of two-way isolated DC-DC converter containing active snubber | |
| CN102647100B (en) | Integrated Buck-flyback high power factor converter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |