CN116707275B - Auxiliary circuit, power supply system and electronic equipment - Google Patents

Auxiliary circuit, power supply system and electronic equipment Download PDF

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Publication number
CN116707275B
CN116707275B CN202310987115.3A CN202310987115A CN116707275B CN 116707275 B CN116707275 B CN 116707275B CN 202310987115 A CN202310987115 A CN 202310987115A CN 116707275 B CN116707275 B CN 116707275B
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Prior art keywords
power switch
winding
power
state
auxiliary winding
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CN116707275A (en
Inventor
请求不公布姓名
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Ensai Semiconductor Chengdu Co ltd
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Ensai Semiconductor Chengdu Co ltd
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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H02M1/0054—Transistor switching losses
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention discloses an auxiliary circuit, a power supply system and electronic equipment, wherein the auxiliary circuit is applied to the power supply system with a transformer and an input capacitor, the transformer is at least provided with an auxiliary winding and a main-stage winding, and the auxiliary circuit comprises: and an auxiliary winding, a normally-on switch and a second power switch. The auxiliary circuit provided by the invention has a simple structure, can supply power to the outside, and also reduces the switching loss of the power switch.

Description

Auxiliary circuit, power supply system and electronic equipment
Technical Field
The invention relates to the technical field of power conversion, in particular to an auxiliary circuit, a power supply system and electronic equipment.
Background
Each power supply system has its own power supply circuit, especially for the power supply system of the AC-DC power converter, since the bus voltage has a wide variation range, and generally includes the whole voltage range of 85Vac-265Vac, no matter the high voltage of the bus is applied to power the driving chip of the power supply system through the resistor, JFET or high voltage MOSFET, the power supply efficiency of the whole power supply system is reduced, the temperature of the power supply system is increased, the volume is increased, and the cost is increased, so that improvement is necessary.
Disclosure of Invention
In a first aspect of the present invention,
the embodiment of the invention provides an auxiliary circuit, which is applied to a power supply system with a transformer and an input capacitor, wherein the transformer is at least provided with an auxiliary winding and a main-stage winding, and the auxiliary circuit comprises:
the auxiliary winding is provided with two ends, wherein the first end of the auxiliary winding is coupled with the first end of the input capacitor, or is coupled with the first end of the input capacitor after passing through the capacitor, and the second end of the input capacitor is grounded;
a normally-on switch having a first end, a second end and a control end, wherein the first end is coupled to the second end of the auxiliary winding, the second end is configured to provide a supply voltage for supplying power;
the second power switch is provided with a first end, a second end and a control end, wherein the first end is coupled with the second end of the normally-on switch; the second power switch is configured to control current flowing through the auxiliary winding.
Preferably, the auxiliary circuit turns on a part or all of a pulse time before the primary winding of the transformer starts to charge, so that current flowing through the secondary power switch flows through the auxiliary winding.
Preferably, the auxiliary winding and the main winding have the same-name end position, and when the first power switch is switched from the off state to one pulse time or a part or all of pulse time before the first power switch is switched from the on state, the second power switch is switched on, current flows into the auxiliary winding, through the coupling relation between the main winding and the auxiliary winding of the transformer, the voltage across the two ends of the first power switch is reduced from a first potential when the first power switch is turned off to a second lower potential, and then the first power switch is switched from the off state to the on state, so that the switching loss of the first power switch is lower; or (b)
The auxiliary winding and the main winding have opposite homonymous end positions, the second power switch is conducted in a first period of one pulse time before the first power switch is switched from an off state to an on state, current flows into the auxiliary winding, and through the coupling relation between the main winding and the auxiliary winding of the transformer, the voltage across the two ends of the first power switch rises from the potential when the first power switch is turned off to a first potential; in a second period of one pulse time before the first power switch is switched from the off state to the on state, the second power switch is turned off, and after the voltage across the two ends of the first power switch is reduced from the first potential to a second potential which is lower through the coupling relation between the main winding and the auxiliary winding of the transformer, the first power switch is switched from the off state to the on state, so that the switching loss of the first power switch is lower.
Preferably, the normally-on switch is one of a junction field effect transistor, a depletion type metal oxide semiconductor field effect transistor, or a depletion type gallium nitride transistor GaN.
In a second aspect of the present invention,
the embodiment of the invention provides a power supply system, which at least comprises the auxiliary circuit in any one of the first aspect, a control module and a driving module, wherein the auxiliary circuit supplies power to the driving module through a second end of a normally-on switch; the first control signal output by the control module is coupled with the control end of the first power switch through the driving module to control the on and off of the first power switch; the second control signal output by the control module is coupled with the control end of the second power switch and controls the on and off of the second power switch.
Preferably, the control module controls the second power switch in the auxiliary circuit to conduct for a part or all of a pulse time before the first power switch is switched from the off state to the on state, so that the current flowing through the second power switch flows through the auxiliary winding.
Preferably, the auxiliary winding and the main winding of the transformer of the power supply system have the same-name end position, the second power switch is conducted for a part or all of pulse time before the first power switch is switched from the off state to the on state, current flows into the auxiliary winding, and after the voltage across the two ends of the first power switch is reduced from a first potential when the first power switch is turned off to a lower second potential through the coupling relation between the main winding and the auxiliary winding of the transformer, the first power switch is switched from the off state to the on state, so that the switching loss of the first power switch is lower; or (b)
The auxiliary winding and the main winding of the transformer of the power supply system have opposite homonymous end positions, the second power switch is conducted in a first period of one pulse time before the first power switch is switched from an off state to an on state, current flows into the auxiliary winding, and the voltage across the two ends of the first power switch rises from the potential when the first power switch is turned off to a first potential through the coupling relation between the main winding and the auxiliary winding of the transformer; in a second period of one pulse time before the first power switch is switched from the off state to the on state, the second power switch is turned off, and after the voltage across the two ends of the first power switch is reduced from the first potential to a second potential which is lower through the coupling relation between the main winding and the auxiliary winding of the transformer, the first power switch is switched from the off state to the on state, so that the switching loss of the first power switch is lower.
Preferably, the power supply system further comprises an output capacitor and a power stage coupled in parallel to the load; the power stage includes at least a primary winding of a transformer, a freewheel module, and a first power switch.
Preferably, the connection relation between the power stage and the input capacitor and the connection relation between the power stage and the output capacitor can be combined to form one of a buck power supply system, a boost power supply system, a flyback power supply system and a buck-boost power supply system.
In a third aspect, an embodiment of the present invention provides an electronic device, including the power supply system of any one of the second aspects.
The technology of the invention has the following advantages:
the auxiliary circuit based on the embodiment of the invention has a simple structure, can supply power to the outside, does not need an external power supply capacitor, and reduces the switching loss of the power switch.
Drawings
FIG. 1 is a simplified block diagram of an auxiliary circuit of one embodiment of the present invention;
FIG. 2a is a block diagram of a power supply system with auxiliary circuitry according to one embodiment of the invention;
FIG. 2b is a block diagram of a power supply system with auxiliary circuitry in accordance with another embodiment of the present invention;
FIG. 2c is a block diagram of a power supply system with auxiliary circuitry in accordance with yet another embodiment of the present invention;
FIG. 2d is a block diagram of a power supply system with auxiliary circuitry in accordance with yet another embodiment of the present invention;
FIG. 2e is a block diagram of a power supply system with auxiliary circuitry according to another embodiment of the present invention;
FIG. 3a is a schematic diagram of a partial node waveform of an embodiment of the present invention;
fig. 3b is a schematic diagram of a partial node waveform of another embodiment of the present invention.
Various features and elements are not drawn to scale in accordance with conventional practice in the drawings in order to best illustrate the specific features and elements associated with the invention. In addition, like elements/components are referred to by the same or similar reference numerals among the different drawings.
Description of the reference numerals
11: first power supply system
100: first power stage
110: auxiliary circuit
12: second power supply system
120: second power stage
121: freewheel module
13: third power supply system
130: third power stage
14: fourth power supply system
140: fourth power stage
141: absorption circuit
15: fifth power supply system
150: fifth power stage
16: sixth power supply system
160: sixth power stage
Symbol description
MP: first power switch
MA: second power switch
MJ: normally-on switch
GP: first control signal
GA: second control signal
Vds: cross-over pressure
T1: transformer
Lp: main-stage winding
Ls: secondary winding
La: auxiliary winding
Ip: main stage winding current
Ia: auxiliary winding current
Is: secondary winding current
Nps: turns ratio
Dlp: absorption diode
Clp: absorption capacitor
CIN: input capacitance
CO: output capacitor
VIN: input voltage
VCC: supply voltage
VO: load voltage
t1 to t3: time point
T12: during a first period
T23: second period
T13: pulse time.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In a first aspect, an embodiment of the present invention provides an auxiliary circuit.
As shown in fig. 1, an auxiliary circuit 110 is applied to a power supply system 11 having a transformer T1 and an input capacitor CIN, the transformer T1 having at least an auxiliary winding La and a main stage winding Lp, the auxiliary circuit 110 comprising: the auxiliary winding La is provided with two ends, wherein the first end is coupled with the first end of the input capacitor CIN, or is coupled with the first end of the input capacitor CIN after passing through the capacitor, and the second end of the input capacitor CIN is grounded; a normally-on switch MJ having a first terminal coupled to the second terminal of the auxiliary winding La, a second terminal configured to provide a supply voltage VCC for supplying power, and a control terminal; the second power switch MA is provided with a first end, a second end and a control end, wherein the first end is coupled with the second end of the normally-on switch MJ, and the second end is coupled with the ground; the second power switch MA is configured to control the current flowing through the auxiliary winding La.
In one embodiment, as shown in fig. 1, the auxiliary circuit 110 causes the current flowing through the second power switch MA to flow through the auxiliary winding La for some or all of a pulse time before the primary winding Lp of the transformer T1 begins to charge.
The homonymous ends of the two windings of the transformer are defined as follows: when current flows into (or out of) two windings simultaneously from one end of each winding respectively, if magnetic fluxes generated by the two windings are aided, the two ends are called as homonymous ends of the transformer winding, and black dots "·" or asterisks are used for marking. The positions of the homonymous terminals can be defined by themselves, the inflow terminals can be called homonymous terminals, and the outflow terminals can be called homonymous terminals.
In one embodiment, as shown in fig. 1, the auxiliary winding La and the main winding Lp have the same-name end position, and after a part or all of a pulse time before the first power switch MP is switched from the off state to the on state, the second power switch MA is turned on, a current flows into the auxiliary winding La, and through a coupling relationship between the main winding Lp and the auxiliary winding La of the transformer T1, a voltage Vds across the first power switch MP is reduced from a first potential when the first power switch MP is turned off to a second potential which is lower, and then the first power switch MP is switched from the off state to the on state, so that a switching loss of the first power switch MP is lower.
In one embodiment, as shown in fig. 1, the auxiliary winding La and the main winding Lp have opposite identical-name end positions, during a first period of one pulse time before the first power switch MP is switched from the off state to the on state, the second power switch MA is turned on, a current flows into the auxiliary winding La, and a voltage across Vds of the first power switch MP rises from a potential when the first power switch MP is turned off to a first potential through a coupling relationship between the main winding Lp and the auxiliary winding La of the transformer T1; during a second period of one pulse time before the first power switch MP is switched from the off state to the on state, the second power switch MA is turned off, and after the voltage across Vds across the first power switch MP is reduced from the first potential to the second potential lower than the first potential, the first power switch MP is switched from the off state to the on state, so that the switching loss of the first power switch MP is lower.
In one embodiment, as shown in fig. 1, the normally-on switch MJ is a Junction Field Effect Transistor (JFET).
In one embodiment, as shown in fig. 1, the normally-on switch MJ is a depletion-mode metal oxide semiconductor field effect transistor (depletion-mode MOSFET).
In one embodiment, as shown in FIG. 1, normally-on switch MJ is a depletion gallium nitride transistor GaN (D-GaN).
In a second aspect, an embodiment of the present invention provides a power supply system.
The power supply system at least comprises the auxiliary circuit 110 according to any one of the first aspect, the power supply system further comprises a control module and a driving module, and the auxiliary circuit 110 supplies power to the driving module by supplying a power supply voltage VCC to the second terminal of the normally-on switch MJ; the first control signal GP output by the control module is coupled with the control end of the first power switch MP after passing through the driving module, and controls the on and off of the first power switch MP; the second control signal GA output by the control module is coupled to the control end of the second power switch MA and controls the on and off of the second power switch MA.
In one embodiment, as shown in fig. 1, the first power supply system 11 further includes an output capacitor CO, an input capacitor CIN, and a first power stage 100 coupled in parallel with the load; the first power stage 100 comprises at least a main stage winding Lp of a transformer T1, a freewheel module 121 and a first power switch MP.
In one embodiment, as shown in fig. 1, the auxiliary winding La of the transformer T1 of the first power system 11 has the same end position as the main winding Lp, the control module controls, through the driving module, a part or all of a pulse time before the first power switch MP is switched from the off state to the on state (or before the main winding Lp of the transformer T1 begins to charge), the control module controls the second power switch MA in the auxiliary circuit 110 to lead to charge the auxiliary winding La, and reduces, through a coupling relationship between the main winding Lp and the auxiliary winding La of the transformer T1, a voltage across Vds across the first power switch MP serially coupled to the main winding Lp from an initial first potential to a lower second potential, and then the control module controls the first power switch MP to be switched from the off state to the on state (or the main winding Lp of the transformer T1 begins to charge again), so that the switching loss of the first power switch MP is lower.
In one embodiment, a first end of the main stage winding Lp is coupled to a first end of the first power switch MP, and a second end of the first power switch MP is grounded; in one embodiment, the first terminal of the main stage winding Lp is coupled to the second terminal of the first power switch MP, and the first terminal of the first power switch MP is coupled to the input voltage VIN of the first terminal of the input capacitor CIN.
In one embodiment, as shown in fig. 1, the auxiliary winding La and the main winding Lp of the transformer T1 of the first power supply system 11 have opposite identical-name end positions, and during a first period of one pulse time before the first power switch MP is switched from the off state to the on state, the second power switch MA is turned on, a current flows into the auxiliary winding La, and a voltage across the first power switch MP rises from a potential when the first power switch MP is turned off to a first potential through a coupling relationship between the main winding Lp and the auxiliary winding La of the transformer T1; during a second period of one pulse time before the first power switch MP is switched from the off state to the on state, the second power switch MA is turned off, and after the voltage across Vds across the first power switch MP is reduced from the first potential to the second potential lower than the first potential, the first power switch MP is switched from the off state to the on state, so that the switching loss of the first power switch MP is lower.
In one embodiment, the first power system 11 further includes a rectifier bridge, an input terminal of the rectifier bridge is coupled to the ac power, and an input capacitor CIN is coupled to an output terminal of the rectifier bridge, for bypassing the high frequency signal; in one embodiment, the input terminal of the first power system 11 is directly coupled to the dc input voltage VIN, and the input capacitor CIN is used for bypassing the high frequency signal of the input voltage VIN.
In one embodiment, the freewheel module 121 is composed of diodes, and the power stages including the diodes constitute an asynchronous rectification structure.
In one embodiment, the freewheel module 121 is composed of a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), and the power stage including the MOSFET constitutes a synchronous rectification structure.
In one embodiment, as shown in fig. 2a, the second power supply system 12 includes an input capacitance CIN, an output capacitance CO coupled in parallel to a load, an auxiliary circuit 110, a control module, a drive module, and a second power stage 120, the second power stage 120 including a main stage winding Lp, a freewheel module 121, and a first power switch MP; a first terminal of the output capacitor CO is coupled to a first terminal of the input capacitor CIN and a second terminal of the freewheel module 121; the second terminal of the input capacitor CIN is coupled with the ground; the homonymous end of the auxiliary winding La is coupled with the homonymous end of the main stage winding Lp and the second end of the output capacitor CO; the same-name end of the auxiliary winding La is also the first end of the auxiliary winding La, the non-same-name end of the auxiliary winding La is also the second end of the auxiliary winding La, after the first end of the auxiliary winding La passes through the output capacitor CO, the first end of the auxiliary winding La is coupled with the input voltage VIN of the first end of the input capacitor CIN, the second end of the auxiliary winding La is coupled with the first end of the normally-on switch MJ, the second end of the normally-on switch MJ provides a supply voltage VCC for supplying power, the control end of the normally-on switch MJ is coupled with the ground or is coupled to a voltage node, in one embodiment, the normally-on switch MJ is a Junction Field Effect Transistor (JFET), when the control end of the JFET is grounded, the highest voltage of the second end of the JFET is the pinch-off voltage of the JFET, the normally-on switch MJ is used for supplying power for a driving module, the first end of the second power switch MA is coupled with the second end of the normally-on switch MJ, the second end of the second power switch MA is grounded, the control end of the second power switch MA is coupled with the control module, and the output control signal of the second power switch MA can flow through the auxiliary winding La and the auxiliary winding La can be controlled; the non-homonymous end of the main stage winding Lp is coupled with the first end of the first power switch MP and the first end of the freewheel module 121; the control end of the first power switch MP is coupled with a first control signal GP output by the control module through the driving module, the second end of the first power switch MP is grounded, or is grounded after passing through a current detection resistor, and the first control signal GP and the second control signal GA output by the control module control the on and off of the first power switch MP and the second power switch MA.
The second power supply system 12 belongs to a step-down power supply system, when the first power switch MP is turned on, the input voltage VIN charges the main winding Lp through the load and the output capacitor CO, at this time, the voltage drop on the main winding Lp is approximately VIN-VO (neglecting the conduction voltage drop of the first power switch MP), and by the coupling relationship of the transformer T1, the voltage drop on the auxiliary winding La is also kept at VIN-VO or approximately equal to VIN-VO under the condition that the turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during charging of the main stage winding Lp, the voltage at the first terminal of the normally-on switch MJ is (VIN-VO) - (VIN-VO) =0; during the turn-off period of the first power switch MP, the load voltage VO on the output capacitor CO discharges the main winding Lp, and at this time, the voltage drop on the main winding Lp is approximately-VO, and by the coupling relationship of the transformer T1, the voltage drop on the auxiliary winding La is also maintained at-VO or approximately-VO under the condition that the turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during discharge of the main stage winding Lp, the voltage at the first terminal of the normally-on switch MJ is (VIN-VO) - (-VO) =vin.
In combination with the schematic waveform diagram shown in figure 3a and the block diagram of the second power supply system 12 shown in figure 2a,
The auxiliary winding La and the main winding Lp have the same-name ends at the same position, the first control signal GP output by the control module changes from low level to high level to control a part (such as a first period T12) or all (the whole pulse time T13) of a pulse time T13 before the first power switch MP changes from off state to on state, the second power switch MA is turned on, current flows into the auxiliary winding La, through the coupling relation between the main winding Lp and the auxiliary winding La of the transformer T1, the auxiliary winding current Ia is coupled into the main winding Lp, so that energy in the parasitic capacitance Coss at both ends of the first power switch MP is transferred into the main winding Lp, the voltage Vds at both ends of the first power switch MP is reduced from a first potential when the first power switch MP is turned off to a second potential which is lower, in one embodiment, the first potential is the input voltage VIN, the second potential is zero potential or a potential close to zero, the first control signal GP output by the control module changes from low level to on state, and the loss is reduced from the first power switch MP to off state.
In the waveform diagram shown in fig. 3a, the time point T1 corresponds to a time point when the second power switch MA is turned on in preference to the first power switch MP, and in one embodiment, the time point T1 is generated in response to the demagnetization end signal of the transformer T1; in one embodiment, the t1 time point is generated in response to a trough of the voltage across the first power switch MP Vds (either the first trough or the nth trough); in one embodiment, the t1 time point is generated in response to a pulse width modulated signal (PWM signal) of the second power supply system 12.
In the waveform schematic shown in fig. 3a, the time point T3 corresponds to the on time point of the first power switch MP, the period between the time point T1 and the time point T3 is the pulse time T13 for the second power switch MA to be turned on, the length of the pulse time T13 and the magnitude of the auxiliary winding current Ia flowing through the auxiliary winding La determine the amplitude of the voltage across Vds of the first power switch MP from the initial first potential VIN to the lower second potential, and in one embodiment, the pulse time T13 and the auxiliary winding current Ia are optimized such that the second potential approaches zero potential, and then the first power switch MP is turned on again to realize the switching of the first power switch MP in the zero voltage state;
in the waveform diagram shown in fig. 3a, the time point T3 is also the off time point of the second power switch MA and is also the on time point of the first power switch MP, in one embodiment, the off time point of the second power switch MA is a time point T2 between the time point T1 and the time point T3, and the second power switch MA is not turned on during the whole pulse time T13, but is turned on only during the first period T12 of the pulse time T13 and is turned off during the second period T23.
In one embodiment, the first terminal of the auxiliary winding La of the second power supply system 12 shown in fig. 2a may also be coupled to the first terminal of the input capacitance CIN, and a specific analysis may refer to the foregoing analysis, and the description will not be repeated.
In one embodiment, as shown in fig. 2b, the third power supply system 13 also belongs to a step-down power supply system, and the difference between the third power supply system 13 and the second power supply system 12 is that the same-name ends of the transformers T1 are located differently, the transformers T1 in the second power supply system 12 have the same-name ends of the same location, and the transformers T1 in the third power supply system 13 have opposite-name ends of the same location.
The connection relation of the third power supply system 13 is shown in fig. 2b, and the description will not be repeated. In the third power supply system 13, when the first power switch MP is turned on, the input voltage VIN charges the main winding Lp through the load and the output capacitor CO, and at this time, the voltage drop on the main winding Lp is approximately VIN-VO (neglecting the conduction voltage drop of the first power switch MP), and by the coupling relationship of the transformer T1, the voltage drop on the auxiliary winding La is kept to be- (VIN-VO) or approximately equal to- (VIN-VO) when the number of turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during charging of the main stage winding Lp, the voltage at the first terminal of the normally-on switch MJ is (VIN-VO) + (VIN-VO) =2 (VIN-VO); when the first power switch MP is turned off, the load voltage VO on the output capacitor CO discharges the main winding Lp, at this time, the voltage drop on the main winding Lp is approximately-VO, and by means of the coupling relationship of the transformer T1, the voltage drop on the auxiliary winding La is kept at VO or approximately equal to VO under the condition that the turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during discharge of the primary winding Lp, the voltage at the first port P1 of the auxiliary control module 1101 is (VIN-VO) -vo=vin-2 VO.
In combination with the schematic waveform diagram shown in figure 3b and the block diagram of the third power supply system 13 shown in figure 2b,
the auxiliary winding La and the main winding Lp of the transformer T1 have opposite-position same-name ends, before the control module controls the output first control signal GP to change from low level to high level to control the first power switch MP to change from off state to on state, the control module outputs the second control signal GA to generate a high level in the first period T12 of the pulse time T13, the second power switch MA in the auxiliary circuit is enabled to conduct for the first period T12 to charge the auxiliary winding La, current flows through the auxiliary winding La, through the coupling relation of the transformer T1, the auxiliary winding current Ia flowing through the auxiliary winding La is coupled to the main winding Lp, the cross voltage Vds at two ends of the first power switch MP is enabled to rise to the first potential VIN (neglecting the conduction voltage drop on the freewheel module 121), in the schematic diagram shown in fig. 3b, the second control signal GA is high level in the first period T12 of the pulse time T13, the second power switch MA is enabled to conduct, the corresponding main winding current Ia with the same direction and the auxiliary winding La is generated on the auxiliary winding La, and the main winding current Ip with the same direction is coupled to the first potential VIN, and the first potential VIN is generated across the main winding is coupled to the first potential winding and the first potential winding is coupled to the first potential winding is connected in series; in the second period T23 of the pulse time T13, the second control signal GA is at a low level, the second power switch MA is turned off, and the voltage across Vds at both ends of the first power switch MP is rapidly reduced from the initial first potential VIN to a lower second potential (for example, a zero potential or a potential close to zero) in the second period T23 through the coupling relationship between the main winding Lp and the auxiliary winding La of the transformer T1, so that the first control signal GP output by the control module becomes at a high level, and the first power switch MP is controlled to be switched from the off state to the on state.
In the waveform diagram shown in fig. 3b, the time point T1 corresponds to a time point when the second power switch MA is turned on prior to the first power switch MP, and in one embodiment, the time point T1 is generated in response to the demagnetization end signal of the transformer T1; in one embodiment, the t1 time point is generated in response to a trough of the voltage across the first power switch MP Vds (either the first trough or the nth trough); in one embodiment, the t1 time point is generated in response to a pulse width modulated signal (PWM signal) of the third power supply system 13.
In the waveform schematic shown in fig. 3b, the time point T3 corresponds to the on time point of the first power switch MP, the first period T12 between the time point T1 and the time point T2 is the pulse time of the second power switch MA, the length of the first period T12, the length of the second period T23, and the magnitude of the auxiliary winding current Ia flowing through the auxiliary winding La determine the amplitude of the voltage across Vds of the first power switch MP from the initial first potential VIN to the lower second potential, and in one embodiment, the three parameters are optimized to make the second potential approach to the zero potential, and then the first power switch MP is turned on again to realize that the first power switch MP is switched in the zero voltage state.
In an embodiment, the first terminal of the auxiliary winding La of the third power supply system 13 shown in fig. 2b may also be coupled to the first terminal of the input capacitance CIN, and a specific analysis may refer to the foregoing analysis, and the description will not be repeated.
In one embodiment, as shown in fig. 2c, the fourth power supply system 14 includes an input capacitor CIN, a load coupled in parallel with an output capacitor CO, an auxiliary circuit 110, a control module, a drive module, a fourth power stage 140 and an absorption circuit 141, the fourth power stage 140 including a primary winding Lp and a secondary winding Ls of a transformer T1, a freewheel module 121 and a first power switch MP; the snubber circuit 141 includes a snubber diode Dlp and a snubber capacitor Clp; the first end of the input capacitor CIN is coupled with the same-name end of the main-stage winding Lp and the second end of the absorption capacitor Clp, the second end of the input capacitor CIN is coupled with the ground, the first end of the absorption capacitor Clp is coupled with the same-name end of the auxiliary winding La and the cathode of the absorption diode Dlp, the same-name end of the auxiliary winding La is also the first end of the auxiliary winding La, the non-same-name end of the auxiliary winding La is the second end of the auxiliary winding La, the first end of the auxiliary winding La is coupled with the input voltage VIN of the first end of the input capacitor CIN after passing through the absorption capacitor Clp, and the second end of the auxiliary winding La is coupled with the first end of the normally-on switch MJ; the second end of the normally-on switch MJ provides a supply voltage VCC for supplying power, the control end of the normally-on switch MJ is coupled to ground or to a voltage node, in one embodiment, the normally-on switch MJ is a Junction Field Effect Transistor (JFET), when the control end of the JFET is grounded, the highest voltage of the second end of the JFET is the pinch-off voltage of the JFET, which is equivalent to that the normally-on switch MJ uses the pinch-off voltage of the JFET to supply power to the driving module, the first end of the second power switch MA is coupled to the second end of the normally-on switch MJ, the second end of the second power switch MA is grounded, the control end of the second power switch MA is coupled to the second control signal GA output by the control module, and by controlling the on and off of the second power switch MA, the current flowing through the auxiliary winding La can be controlled; the non-homonymous end of the main stage winding Lp is coupled with the first end of the first power switch MP and the anode of the absorption diode Dlp, and the control end of the first power switch MP is coupled with a first control signal GP output by the control module after passing through the driving module; the second end of the first power switch MP is grounded or grounded after passing through a current detection resistor, and a first control signal GP and a second control signal GA output by the control module control the on and off of the first power switch MP and the second power switch MA; the first end of the output capacitor CO is coupled with the second end of the follow current module 121, the first end of the follow current module 121 is coupled with the non-homonymous end of the secondary winding Ls, and the homonymous end of the secondary winding Ls is coupled with the second end of the output capacitor CO; or the first end of the output capacitor CO is coupled to the non-homonymous end of the secondary winding Ls, the second end of the output capacitor CO is coupled to the first end of the freewheel module 121, and the second end of the freewheel module 121 is coupled to the homonymous end of the secondary winding Ls.
The fourth power supply system 14 belongs to a flyback power supply system, when the first power switch MP is turned on, the input voltage VIN charges the main winding Lp, at this time, the voltage drop across the main winding Lp is approximately VIN (neglecting the on-voltage drop of the first power switch MP), and by the coupling relationship of the transformer T1, the voltage drop across the auxiliary winding La is also kept at VIN or approximately VIN when the number of turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during charging of the primary winding Lp, the voltage at the first end of the normally-on switch MJ is (vin+ Nps ×vo) -vin= Nps ×vo, (Nps is the turns ratio of the primary winding Lp to the secondary winding Ls); when the first power switch MP Is turned off, the load voltage VO on the output capacitor CO discharges the secondary winding Ls, resulting in a secondary winding current Is charging the output capacitor CO, which Is equivalent to a voltage drop on the primary winding Lp of approximately-Nps x VO (neglecting the on-voltage drop of the snubber diode Dlp), and during the secondary winding Ls discharge, the voltage at the first end of the normally-on switch MJ Is (vin+ Nps x VO) - (-Nps x VO) =vin+2mps x VO.
The operation principle of the auxiliary circuit 110 in the fourth power supply system 14 and the operation principle of implementing the first power switch MP to operate in the zero-voltage switching state are identical to each other compared to the second power supply system 12, and the description will not be repeated.
In one embodiment, the homonymous terminal of the auxiliary winding La in the fourth power supply system 14 may also be coupled to a first terminal of the input capacitance CIN.
In one embodiment, the auxiliary winding La and the main winding Lp in the fourth power supply system 14 have opposite identical ends, and a specific analysis may refer to the analysis of fig. 2b in the specification, and the description will not be repeated.
In one embodiment, as shown in fig. 2d, the fifth power supply system 15 includes an input capacitor CIN, a load coupled in parallel with an output capacitor CO, an auxiliary circuit 110, a control module, a drive module, and a fifth power stage 150, the fifth power stage 150 including a main stage winding Lp, a freewheel module 121, and a first power switch MP; the second end of the output capacitor CO is coupled with the first end of the input capacitor CIN, the homonymous end of the main-stage winding Lp and the homonymous end of the secondary winding La; the same-name end of the auxiliary winding La is also the first end of the auxiliary winding La, the non-same-name end of the auxiliary winding La is also the second end of the auxiliary winding La, the first end of the auxiliary winding La is coupled with the input voltage VIN of the first end of the input capacitor CIN, and the second end of the auxiliary winding La is coupled with the first end of the normally-on switch MJ; the second end of the normally-on switch MJ provides a supply voltage VCC for supplying power, the control end of the normally-on switch MJ is coupled to ground or to a voltage node, in one embodiment, the normally-on switch MJ is a Junction Field Effect Transistor (JFET), when the control end of the JFET is grounded, the highest voltage of the second end of the JFET is the pinch-off voltage of the JFET, which is equivalent to that the normally-on switch MJ uses the pinch-off voltage of the JFET to supply power to the driving module, the first end of the second power switch MA is coupled to the second end of the normally-on switch MJ, the second end of the second power switch MA is grounded, the control end of the second power switch MA is coupled to the second control signal GA output by the control module, and by controlling the conduction and the cut-off of the second power switch, the current flowing through the auxiliary winding La can be controlled; the non-homonymous end of the main-stage winding Lp is coupled with the first end of the first power switch MP and the first end of the follow current module 121, the second end of the follow current module 121 is coupled with the first end of the output capacitor CO, and the control end of the first power switch MP is coupled with a first control signal GP output by the control module after passing through the driving module; the second end of the first power switch MP is grounded or grounded after passing through a current detection resistor, and the first control signal GP and the second control signal GA output by the control module control the on and off of the first power switch MP and the second power switch MA.
The fifth power supply system 15 belongs to a step-up/down power supply system, and when the first power switch MP is turned on, the input voltage VIN charges the main winding Lp, and at this time, the voltage drop across the main winding Lp is approximately VIN (neglecting the on voltage drop of the first power switch MP), and by means of the coupling relationship of the transformer T1, the voltage drop across the auxiliary winding La is also kept at VIN or approximately VIN when the number of turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during charging of the main stage winding Lp, the voltage at the first end of the normally-on switch MJ is VIN-vin=0; when the first power switch MP is turned off, the load voltage VO on the output capacitor CO discharges the main winding Lp, at this time, the voltage drop on the main winding Lp is approximately-VO, and under the condition that the turns of the main winding Lp and the auxiliary winding La are the same or approximately the same, the voltage drop on the auxiliary winding La is also kept to be-VO or approximately equal to-VO through the coupling relation of the transformer T1; during discharge of the main stage winding Lp, the voltage at the first terminal of the normally-on switch MJ is VIN- (-VO) =vin+vo.
The operation principle of the auxiliary circuit 110 in the fifth power supply system 15 and the operation principle of implementing the first power switch MP operating in the zero voltage switching state are identical to those of the second power supply system 12, and the description will not be repeated.
In one embodiment, the homonymous terminal of the auxiliary winding La in the fifth power supply system 15 may also be coupled to the first terminal of the output capacitance CO.
In one embodiment, the auxiliary winding La and the main winding Lp in the fifth power supply system 15 have opposite identical ends, and a specific analysis refers to the analysis of fig. 2b in the specification, and the description will not be repeated.
In one embodiment, as shown in fig. 2e, the sixth power system 16 includes an input capacitor CIN, a load coupled in parallel with an output capacitor CO, an auxiliary circuit 110, a control module, a drive module, and a sixth power stage 160, the sixth power stage 160 including a main stage winding Lp, a freewheel module 121, and a first power switch MP; the first end of the input capacitor CIN is coupled with the homonymous end of the main stage winding Lp and the homonymous end of the secondary winding La; the same-name end of the auxiliary winding La is also the first end of the auxiliary winding La, the non-same-name end of the auxiliary winding La is also the second end of the auxiliary winding La, the first end of the auxiliary winding La is coupled with the input voltage VIN of the first end of the input capacitor CIN, and the second end of the auxiliary winding La is coupled with the first end of the normally-on switch MJ; the second end of the normally-on switch MJ provides a supply voltage VCC for supplying power, the control end of the normally-on switch MJ is coupled to ground or to a voltage node, in one embodiment, the normally-on switch MJ is a Junction Field Effect Transistor (JFET), when the control end of the JFET is grounded, the highest voltage of the second end of the JFET is the pinch-off voltage of the JFET, which is equivalent to that the normally-on switch MJ uses the pinch-off voltage of the JFET to supply power to the driving module, the first end of the second power switch MA is coupled to the second end of the normally-on switch MJ, the second end of the second power switch MA is grounded, the control end of the second power switch MA is coupled to the second control signal GA output by the control module, and by controlling the on and off of the second power switch MA, the current flowing through the auxiliary winding La can be controlled; the non-homonymous end of the main stage winding Lp is coupled with the first end of the first power switch MP and the first end of the follow current module 121, the second end of the follow current module 121 is coupled with the first end of the output capacitor CO, the second end of the output capacitor CO is grounded, and the control end of the first power switch MP is coupled with a first control signal GP output by the control module after passing through the driving module; the second end of the first power switch MP is grounded or grounded after passing through a current detection resistor, and the first control signal GP and the second control signal GA output by the control module control the on and off of the first power switch MP and the second power switch MA.
The sixth power supply system 16 belongs to a boost power supply system, and when the first power switch MP is turned on, the input voltage VIN charges the main winding Lp, at this time, the voltage drop across the main winding Lp is approximately VIN (neglecting the on-voltage drop of the first power switch MP), and by the coupling relationship of the transformer T1, the voltage drop across the auxiliary winding La is also kept at VIN or approximately VIN when the number of turns of the main winding Lp and the auxiliary winding La are the same or approximately the same; during charging of the main stage winding Lp, the voltage at the first end of the normally-on switch MJ is VIN-vin=0; when the first power switch MP is turned off, the difference between the load voltage VO on the output capacitor CO and the input voltage VIN discharges the main winding Lp, at this time, the voltage drop on the main winding Lp is approximately VO-VIN, and the voltage drop on the auxiliary winding La is also kept at VO-VIN or approximately VO-VIN under the condition that the number of turns of the main winding Lp and the number of turns of the auxiliary winding La are the same or approximately the same through the coupling relationship of the transformer T1; during discharge of the main stage winding Lp, the voltage at the first terminal of the normally-on switch MJ is vin+ (VO-VIN) =vo.
The operation principle of the auxiliary circuit 110 in the sixth power supply system 16 and the operation principle of the first power switch MP operating in the zero voltage switching state are identical to each other compared to the second power supply system 12, and the description will not be repeated.
In one embodiment, the homonymous terminal of the auxiliary winding La in the sixth power supply system 16 may also be coupled to the first terminal of the output capacitance CO.
In one embodiment, the auxiliary winding La and the main winding Lp in the sixth power supply system 16 have opposite identical ends, and a specific analysis may refer to the analysis of fig. 2b in the specification, which is not repeated.
In the above embodiments, in order to conveniently, more clearly and simply describe the working principle of the present invention, the description only exemplifies the case that the number of turns of the main winding Lp and the auxiliary winding La of the transformer T1 is the same, and in the actual implementation process, the number of turns of the main winding Lp and the auxiliary winding La of the transformer T1 may be kept different, but the working principle of the present invention is not affected.
As can be seen from the above embodiments, the connection relation between the first power stage 100 of the first power supply system 11 and the input capacitor CIN and the output capacitor CO can be combined to form one of a Buck power supply system (Buck), a Boost power supply system (Boost), a Flyback power supply system (Flyback) and a Buck Boost power supply system (Buck Boost).
In a third aspect, an embodiment of the present invention provides an electronic device, including the power supply system according to any one of the second aspects.
From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:
the auxiliary circuit provided by the application has a simple structure, can supply power to the outside, does not need an external power supply capacitor, reduces the switching loss of the power switch, and improves the efficiency of a power supply system.
It should be noted that, in the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described as different from other embodiments, and identical and similar parts between the embodiments are all enough to be referred to each other.
It should also be noted that, in this document, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the apparatus or elements to be referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application. Moreover, relational terms such as "first" and "second" may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions, or order, and without necessarily being construed as indicating or implying any relative importance. "and/or" means either or both of which may be selected. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or terminal device comprising the element.
The foregoing has outlined rather broadly the more detailed description of the invention in order that the detailed description of the invention that follows may be better understood, and in order that the present contribution to the art may be better appreciated. While various modifications of the embodiments and applications of the invention will occur to those skilled in the art, it is not necessary and not intended to be exhaustive of all embodiments, and obvious modifications or variations of the invention are within the scope of the invention.

Claims (10)

1. An auxiliary circuit for use in a power supply system having a transformer and an input capacitor, the transformer having at least an auxiliary winding and a primary winding, the auxiliary circuit comprising:
the auxiliary winding is provided with two ends, wherein the first end of the auxiliary winding is coupled with the first end of the input capacitor, or is coupled with the first end of the input capacitor after passing through the capacitor, and the second end of the input capacitor is grounded;
the normally-on switch is provided with a first end, a second end and a control end, wherein the first end is coupled with the second end of the auxiliary winding, and the second end is configured to provide a power supply voltage for external power supply and does not need an external power supply capacitor;
The second power switch is provided with a first end, a second end and a control end, wherein the first end is coupled with the second end of the normally-on switch; the second power switch is configured to control current flowing through the auxiliary winding.
2. The auxiliary circuit of claim 1 wherein the second power switch is turned on for a portion or all of a pulse time before the primary winding of the transformer begins to charge, causing current to flow through the second power switch through the auxiliary winding.
3. The auxiliary circuit according to claim 2, wherein the auxiliary winding and the main winding have the same-name end positions, the second power switch is turned on for a part or all of a pulse time before the first power switch is switched from the off state to the on state, current flows into the auxiliary winding, and after the voltage across the first power switch is reduced from a first potential when the first power switch is turned off to a second potential lower than the first potential through a coupling relationship between the main winding and the auxiliary winding of the transformer, the first power switch is switched from the off state to the on state, so that the switching loss of the first power switch is lower; or (b)
The auxiliary winding and the main winding have opposite homonymous end positions, the second power switch is conducted in a first period of one pulse time before the first power switch is switched from an off state to an on state, current flows into the auxiliary winding, and through the coupling relation between the main winding and the auxiliary winding of the transformer, the voltage across the two ends of the first power switch rises from the potential when the first power switch is turned off to a first potential; in a second period of one pulse time before the first power switch is switched from the off state to the on state, the second power switch is turned off, and after the voltage across the two ends of the first power switch is reduced from the first potential to a second potential which is lower through the coupling relation between the main winding and the auxiliary winding of the transformer, the first power switch is switched from the off state to the on state, so that the switching loss of the first power switch is lower.
4. The auxiliary circuit of claim 1, wherein the normally-on switch is one of a junction field effect transistor, or a depletion mode metal oxide semiconductor field effect transistor, or a depletion mode gallium nitride transistor GaN.
5. A power supply system comprising at least an auxiliary circuit according to any one of claims 1 to 4, characterized in that the power supply system further comprises a control module and a drive module, the auxiliary circuit supplying power to the drive module via a second terminal of a normally-on switch; the first control signal output by the control module is coupled with the control end of the first power switch through the driving module to control the on and off of the first power switch; the second control signal output by the control module is coupled with the control end of the second power switch and controls the on and off of the second power switch.
6. The power system of claim 5, wherein the control module controls the second power switch in the auxiliary circuit to conduct for a portion or all of a pulse time before the first power switch is switched from the off state to the on state, such that current flowing through the second power switch flows through the auxiliary winding.
7. The power supply system according to claim 6, wherein the auxiliary winding and the main winding of the transformer of the power supply system have the same-name end position, and the second power switch is turned on for a part or all of a pulse time before the first power switch is switched from the off state to the on state, current flows into the auxiliary winding, and the voltage across the first power switch is reduced from a first potential when the first power switch is turned off to a lower second potential through a coupling relation between the main winding and the auxiliary winding of the transformer, and then the first power switch is switched from the off state to the on state, so that the switching loss of the first power switch is lower; or (b)
The auxiliary winding and the main winding of the transformer of the power supply system have opposite homonymous end positions, the second power switch is conducted in a first period of one pulse time before the first power switch is switched from an off state to an on state, current flows into the auxiliary winding, and the voltage across the two ends of the first power switch rises from the potential when the first power switch is turned off to a first potential through the coupling relation between the main winding and the auxiliary winding of the transformer; in a second period of one pulse time before the first power switch is switched from the off state to the on state, the second power switch is turned off, and after the voltage across the two ends of the first power switch is reduced from the first potential to a second potential which is lower through the coupling relation between the main winding and the auxiliary winding of the transformer, the first power switch is switched from the off state to the on state, so that the switching loss of the first power switch is lower.
8. The power system of claim 5, further comprising an output capacitor and a power stage coupled in parallel with the load; the power stage includes at least a primary winding of a transformer, a freewheel module, and a first power switch.
9. The power system of claim 8, wherein the power stage is coupled to the input capacitor and the output capacitor in a combination to form one of a buck power system, a boost power system, a flyback power system, and a buck-boost power system.
10. An electronic device comprising the power supply system of any one of claims 5 to 9.
CN202310987115.3A 2023-08-08 2023-08-08 Auxiliary circuit, power supply system and electronic equipment Active CN116707275B (en)

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JP2005073394A (en) * 2003-08-25 2005-03-17 Sanken Electric Co Ltd Switching power supply unit
CN101355308A (en) * 2008-08-29 2009-01-28 浙江大学 Magnetic-integrated zero-voltage zero-current soft switch full bridge circuit
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