CN117200586B

CN117200586B - Auxiliary power supply, power supply system and power supply equipment

Info

Publication number: CN117200586B
Application number: CN202311462102.0A
Authority: CN
Inventors: 请求不公布姓名
Original assignee: Ensai Semiconductor Chengdu Co ltd
Current assignee: Ensai Semiconductor Chengdu Co ltd
Priority date: 2023-11-06
Filing date: 2023-11-06
Publication date: 2024-02-06
Anticipated expiration: 2043-11-06
Also published as: CN117200586A

Abstract

The invention discloses an auxiliary power supply, a power supply system and power supply equipment, wherein the auxiliary power supply is applied to the power supply system with a transformer and a first power switch, the transformer is provided with at least an auxiliary winding and a main-stage winding, the main-stage winding is coupled with the first power switch in series, and the auxiliary power supply comprises: the magnetic induction module, the power supply capacitor and the auxiliary module. Compared with the prior art, the invention improves the efficiency of the power supply system.

Description

Auxiliary power supply, power supply system and power supply equipment

Technical Field

The invention relates to the technical field of power conversion, in particular to an auxiliary power supply, a power supply system and power supply equipment.

Background

Each power supply system has its own power supply, 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, the present invention provides an auxiliary power supply for use in a power supply system having a transformer and a first power switch, the transformer having at least an auxiliary winding and a main stage winding, the main stage winding being coupled in series with the first power switch, the auxiliary power supply comprising:

a magnetic induction module having two ends, wherein a first end is coupled to a common node of a primary winding of the transformer and the first power switch, the magnetic induction module including at least an auxiliary winding of the transformer;

a power supply capacitor for providing power supply voltage for external power supply;

the auxiliary module is coupled with the second end of the magnetic induction module, is coupled with the power supply capacitor, at least comprises a second power switch, and can control the auxiliary winding to charge the power supply capacitor or not to flow current by controlling the state of the second power switch.

Preferably, the magnetic induction module further comprises a diode having an anode and a cathode, wherein the anode is coupled to the first end of the magnetic induction module, the cathode is coupled to the first end of the auxiliary winding, and the second end of the auxiliary winding is coupled to the second end of the magnetic induction module; or (b)

The magnetically susceptible module further includes a diode having an anode coupled to the second end of the auxiliary winding and a cathode coupled to the second end of the magnetically susceptible module, the first end of the auxiliary winding being coupled to the first end of the magnetically susceptible module.

Preferably, the auxiliary module is provided with at least three ports, the first port is coupled with the second end of the magnetic induction module, the second port is coupled with a second control signal, the second control signal controls the state of the second power switch, and the third port provides electric voltage to supply power to the outside; or (b)

The auxiliary module is provided with at least four ports, wherein the first port is coupled with the second end of the magnetic induction module, the second port is coupled with a second control signal, the second control signal controls the state of the second power switch, the third port provides electric voltage to supply power to the outside, and the fourth port outputs a demagnetizing signal indicating the end of demagnetization of the transformer.

Preferably, the auxiliary module comprises a second power switch, a first end of the second power switch is coupled with a first port of the auxiliary module, a control end of the second power switch is coupled with a second port of the auxiliary module, a second end of the second power switch is coupled with a power supply capacitor and a third port of the auxiliary module, and the third port outputs power supply voltage to supply power to the outside; or (b)

The auxiliary module comprises a second power switch and a detection module, wherein a first end of the second power switch is coupled with a first port of the auxiliary module, a control end of the second power switch is coupled with a second port of the auxiliary module, and the detection module outputs a demagnetizing signal indicating the end of demagnetization of the transformer to a fourth port of the auxiliary module by detecting the voltage of the first end or the control end of the second power switch; the second end of the second power switch is coupled with the power supply capacitor and a third port of the auxiliary module, and the third port outputs power supply voltage to supply power to the outside; or (b)

The auxiliary module comprises a second power switch, a normally-on switch and a detection module, wherein a first end of the normally-on switch is coupled with a first port of the auxiliary module, a second end of the normally-on switch is coupled with a first end of the second power switch, and the detection module outputs a demagnetizing signal indicating the end of demagnetization of the transformer to a fourth port of the auxiliary module by detecting the voltage of the first end or the control end of the normally-on switch; the control end of the second power switch is coupled with the second port of the auxiliary module, the second end of the second power switch is coupled with the power supply capacitor and the third port of the auxiliary module, and the third port outputs power supply voltage to supply power to the outside.

Preferably, the second power switch of the auxiliary power supply is turned on for a part or all of a pulse time before the main winding of the transformer starts to charge, so that the current flowing through the second power switch flows through the auxiliary winding to charge the power supply capacitor.

Preferably, the auxiliary winding and the main winding have the same-name ends at the same position, the second power switch is conducted at 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 through the auxiliary winding to charge the power supply capacitor, 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 is reduced from a first potential when the first power switch is turned off to a lower second 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 are provided with homonymous ends at opposite positions, the second power switch is conducted in a first period of one pulse time before the first power switch is switched from a cut-off state to a conduction state, current flows through the auxiliary winding to charge a power supply capacitor, and through a 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 a potential when the first power switch is cut-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.

In a second aspect, the present invention provides a power supply system, at least including the auxiliary power supply according to any one of the first aspects, the power supply system further including an input capacitor, an output capacitor, a control module, and a power stage; the power stage at least comprises a main stage winding of the transformer, a first power switch and a follow current module, wherein a first control signal output by the control module is coupled with a control end of the first power switch 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 through the auxiliary module to control the on and off of the second power switch; the connection relation between the power level and the input capacitor and the output capacitor can be combined to form any one of a buck power supply system, a boost power supply system, a flyback power supply system and a boost power supply system.

Preferably, the control module controls the second power switch in the auxiliary power supply 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 to charge the power supply capacitor.

Preferably, the auxiliary winding and the main winding of the transformer of the power supply system have the same-name ends at the same position, and when the first power switch is switched from the off state to one pulse time or all pulse time before the first power switch is switched to the on state, the second power switch is switched on, current flows through the auxiliary winding to charge the power supply capacitor, 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 is reduced from a first potential when the first power switch is turned off to a second potential which is lower, and then the first power switch is switched to the on state from the off 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 are provided with homonymous ends at opposite 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 through the auxiliary winding to charge the power supply capacitor, 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.

In a third aspect, the present invention provides a power supply arrangement comprising the power supply system of any one of the second aspects.

The technology of the invention has the following advantages:

based on the auxiliary power supply, the auxiliary winding for reducing the switching loss of the power supply system is multiplexed, and the auxiliary winding can bear the high voltage of the bus to provide power for the driving chip of the whole power supply system; and the detection of the demagnetizing state of the transformer is realized through the auxiliary power supply, so that the cost of the power supply system is reduced.

Drawings

FIG. 1a is a simplified block diagram of a power supply system of one embodiment of the present invention;

FIG. 1b is a block diagram of a power system with an auxiliary power source in accordance with one embodiment of the present invention;

FIG. 1c is a block diagram of a power supply system with an auxiliary power supply in accordance with another embodiment of the present invention;

FIG. 1d is a block diagram of a power supply system with an auxiliary power supply according to yet another embodiment of the present invention;

FIG. 1e is a block diagram of a power supply system with an auxiliary power supply in accordance with yet another embodiment of the present invention;

FIG. 1f is a block diagram of a power supply system with an auxiliary power supply in accordance with yet another embodiment of the present invention;

FIGS. 2 a-2 c are different embodiments of the auxiliary module of the present invention;

FIG. 2d is one embodiment of a detection module of the present invention;

fig. 3 a-3 c are schematic waveforms of a portion of a node according to one 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 level, 110: auxiliary power supply, 12: second power supply system, 120: second power level, 121: freewheel module, 13: third power supply system, 14: fourth power supply system, 140: fourth power level, 15: fifth power supply system, 150: fifth power stage, 16: sixth power supply system, 160: and a sixth power level.

Symbol description

MP: first power switch, MJ: normally-on switch, MA: second power switch, GP: first control signal, GA: second control signal, coss: parasitic capacitance, CP: supply capacitor, TS: transformer, lp: primary winding, ls: secondary winding, la: auxiliary winding, ip: primary winding current, ia: auxiliary winding current, is: secondary winding current, nps: turns ratio, D1: diode, CIN: input capacitance, CO: output capacitance, VIN: input voltage, VCC: supply voltage, VO: load voltage, cdg: transcapacitive, VREF: reference voltage, SWA: detection signal, ZXC: demagnetizing signal, rsn: pull-down resistors, P1-P4: first port-fourth port, T1-T3: time point, T13: pulse time, T12: during the first period, T23: during the second period, vds: cross-pressure, LX: public node, VP1: the voltage of the first port P1.

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, the present invention provides an auxiliary power supply. As shown in fig. 1a, an auxiliary power supply 110 is applied to a first power supply system 11 having a transformer TS and a first power switch MP, the transformer TS has at least an auxiliary winding La and a main winding Lp, the main winding Lp is coupled in series with the first power switch MP, and the auxiliary power supply 110 includes: the magnetic induction module is provided with two ends, wherein the first end is coupled with a common node of the main-stage winding Lp of the transformer TS and the first power switch MP, and at least comprises an auxiliary winding La of the transformer TS; a power supply capacitor CP for supplying power to the outside with a power supply voltage VCC; the auxiliary module is coupled with the second end of the magnetic induction module, is coupled with the power supply capacitor CP, at least comprises a second power switch MA, and can control the auxiliary winding La to charge the power supply capacitor CP or not to flow current by controlling the state of the second power switch MA.

In one embodiment, the magnetically susceptible module further comprises a diode D1 having an anode coupled to the first end of the magnetically susceptible module and a cathode coupled to the first end of the auxiliary winding La

Is coupled to the second end of the magnetically susceptible module.

In one embodiment, the magnetically susceptible module further comprises a diode D1 having an anode coupled to the second end of the auxiliary winding La and a cathode coupled to the second end of the magnetically susceptible module, the first end of the auxiliary winding La being coupled to the first end of the magnetically susceptible module.

In one embodiment, the auxiliary module has at least three ports, the first port P1 is coupled to the second end of the magnetically sensitive module, the second port P2 is coupled to the second control signal GA, the second control signal GA controls the state of the second power switch MA, and the third port P3 provides the electric voltage VCC to externally supply power.

In one embodiment, the states of the second power switch MA include an on state and an off state, and when the second control signal GA is at a high level, the second power switch MA is in the on state; when the second control signal GA is at the second level, the second power switch MA is in the off state.

In one embodiment, the auxiliary module has at least four ports, the first port P1 is coupled to the second end of the magnetic induction module, the second port P2 is coupled to the second control signal GA, the second control signal GA controls the state of the second power switch MA, the third port P3 provides the electric voltage VCC to externally supply power, and the fourth port P4 outputs the demagnetizing signal ZXC indicating the end of demagnetization of the transformer TS.

In one embodiment, as shown in fig. 2a, the auxiliary module La includes a second power switch MA, a first end of the second power switch MA is coupled to a first port P1 of the auxiliary module, a control end of the second power switch MA is coupled to a second port P2 of the auxiliary module, a second end of the second power switch MA is coupled to a third port P3 of the auxiliary module, and the third port P3 is coupled to a supply capacitor CP, and simultaneously a supply voltage VCC is generated to supply power to the outside; when the second control signal GA is at a high level, the second power switch MA is turned on, the current flowing through the auxiliary winding La charges the power supply capacitor CP through the diode D1 and the second power switch MA, and generates a power supply voltage VCC on the power supply capacitor CP to supply power to the outside, for example, the power supply voltage VCC supplies power to the control module; when the second control signal GA is at a low level, the second power switch MA is turned off, and the power supply capacitor CP provides a power supply voltage to supply power to the outside.

In one embodiment, as shown in fig. 2b, the auxiliary module includes a second power switch MA, a first end of which is coupled to a first port P1 of the auxiliary module, a control end of which is coupled to a second port P2 of the auxiliary module, and a detection module, which outputs a demagnetizing signal ZXC indicating the end of demagnetization of the transformer TS to a fourth port P4 of the auxiliary module by detecting a voltage of the first end or the control end of the second power switch MA; in one embodiment, the oscillation signal of the second end of the auxiliary winding La is coupled to the first end of the second power switch MA, and the detection module detects the voltage of the first end of the second power switch MA through the voltage dividing resistor, so as to realize detection of the demagnetizing state of the transformer TS; in one embodiment, after the oscillation signal at the second end of the auxiliary winding La is coupled to the first end of the second power switch MA, the oscillation signal is coupled to the control end of the second power switch MA through a transcapacitive Cdg between the first end and the control end of the second power switch MA, the detection module detects the voltage of the control end of the second power switch MA, so as to realize detection of the demagnetized state of the transformer TS, and when the detection module detects the oscillation signal at the control end of the second power switch MA, the second control signal can be set in a weak pull-down state with higher impedance; the second end of the second power switch MA is coupled to the third port P3 of the auxiliary module, and the third port P3 is coupled to the supply capacitor CP, and simultaneously generates a supply voltage VCC to supply power to the outside; when the second control signal GA is at a high level, the second power switch MA is turned on, the current flowing through the auxiliary winding La charges the power supply capacitor CP through the diode D1 and the second power switch MA, and generates a power supply voltage VCC on the power supply capacitor CP to supply power to the outside, for example, the power supply voltage VCC supplies power to the control module; when the second control signal GA is at a low level, the second power switch MA is turned off, and the power supply capacitor CP provides a power supply voltage to supply power to the outside.

In one embodiment, as shown in fig. 2c, the auxiliary module includes a second power switch MA, a normally-on switch MJ, and a detection module, wherein a first end of the normally-on switch MJ is coupled to a first port P1 of the auxiliary module, a second end of the normally-on switch MJ is coupled to a first end of the second power switch MA, and the detection module outputs a demagnetization signal ZXC indicating that demagnetization of the transformer TS is completed to a fourth port P4 of the auxiliary module by detecting a voltage of the first end or the control end of the normally-on switch MJ; in one embodiment, an oscillation signal of a second end of the auxiliary winding La is coupled to a first end of the normally-on switch MJ, and the detection module detects the voltage of the first end of the normally-on switch MJ through a voltage dividing resistor to realize detection of a demagnetizing state of the transformer TS; in one embodiment, after the oscillation signal at the second end of the auxiliary winding La is coupled to the first end of the normally-on switch MJ, the oscillation signal is coupled to the control end of the normally-on switch MJ through a transcapacitive Cdg between the first end and the control end of the normally-on switch MJ, the detection module detects the voltage of the control end of the normally-on switch MJ, so as to realize detection of the demagnetizing state of the transformer TS, and when the detection module detects the oscillation signal at the control end of the normally-on switch MJ, the control end of the normally-on switch MJ can be set in a weak pull-down state with higher impedance; the control end of the second power switch MA is coupled to the second port of the auxiliary module, the second end of the second power switch MA is coupled to the third port P3 of the auxiliary module, the third port P3 is coupled to the supply capacitor CP, and the supply voltage VCC is generated to supply power to the outside. When the second control signal GA is at a high level, the second power switch MA is turned on, the current flowing through the auxiliary winding La charges the power supply capacitor CP through the diode D1, the normally-on switch MJ and the second power switch MA, and generates a power supply voltage VCC on the power supply capacitor CP to supply power to the outside, for example, the power supply voltage VCC supplies power to the control module; when the second control signal GA is at a low level, the second power switch MA is turned off, and the power supply capacitor CP provides a power supply voltage to supply power to the outside.

In one embodiment, as shown in fig. 2c, the normally-on switch MJ is a Junction Field Effect Transistor (JFET), and in one embodiment, when the control terminal of the JFET is pulled down to ground by the pull-down resistor, the highest voltage at the second terminal of the JFET is the pinch-off voltage of the JFET, which is equivalent to that the normally-on switch MJ charges the power supply capacitor CP with the pinch-off voltage of the JFET, and the power supply capacitor CP provides the power supply voltage VCC to the outside.

In one embodiment, as shown in fig. 2c, 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. 2c, normally-on switch MJ is a depletion gallium nitride transistor GaN (D-GaN).

In one embodiment, as shown in fig. 2d, the detection module includes a hysteresis comparator and a pull-down resistor Rsn, wherein a first input terminal of the hysteresis comparator is coupled to the reference voltage VREF, a second input terminal of the hysteresis comparator is coupled to the detection signal SWA of the control terminal of the second power switch MA or the normally-on switch MJ, and as can be seen in conjunction with the partial node waveform diagram shown in fig. 3c, when the discharging of the transformer TS is completed, the second terminal of the auxiliary winding La of the transformer TS starts to oscillate, and when the oscillation signal is coupled to the control terminal of the second power switch MA or the normally-on switch MJ, the detection signal SWA is compared with the reference voltage VREF to generate the demagnetizing signal ZXC.

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. 2d, when the auxiliary winding La and the main winding Lp have the same-name ends at the same position, during the demagnetization of the transformer TS, the detection module outputs the demagnetization signal ZXC indicating the end of the demagnetization of the transformer TS when the voltage of the detection signal SWA at the control end of the second power switch MA or the normally-on switch MJ is lower than the preset reference voltage VREF.

In one embodiment, as shown in fig. 2d, when the auxiliary winding La and the main winding Lp have the same-name ends with opposite positions, during the demagnetization of the transformer TS, the detection module outputs the demagnetization signal ZXC indicating the end of the demagnetization of the transformer TS when the voltage of the detection signal SWA of the control end of the second power switch MA or the normally-on switch MJ is higher than the preset reference voltage VREF.

In one embodiment, the working principle of the detection module of the present invention may be further understood with reference to fig. 2d and 3c, where the detection module includes a hysteresis comparator and a pull-down resistor Rsn, and a first input terminal of the hysteresis comparator is coupled to a preset reference voltage VREF, and in one embodiment, the preset reference voltage VREF is zero voltage; the second input end of the hysteresis comparator is coupled to the first end of the pull-down resistor Rsn and the detection signal SWA of the control end of the second power switch MA or the normally-on switch MJ, the second end of the pull-down resistor Rsn is coupled to the preset reference voltage VREF or zero voltage, after the demagnetization of the transformer TS is finished, the oscillation signal of the second end of the auxiliary winding La is coupled to the control end of the second power switch MA or the normally-on switch MJ through the parasitic transcapacitive between the first end and the control end of the second power switch MA or the normally-on switch MJ, so as to generate the detection signal SWA, and when the voltage of the detection signal SWA of the second input end of the hysteresis comparator is lower than the voltage VREF of the first input end (at this time, the first input end is equivalent to the in-phase end of the hysteresis comparator, the second input end is equivalent to the reverse phase end of the hysteresis comparator), the output end of the hysteresis comparator outputs the demagnetization signal ZXC representing the completion of the demagnetization of the transformer TS. In one embodiment, the demagnetization signal ZXC changes from low to high, indicating that the demagnetization of the transformer TS is finished.

In one embodiment, as shown in fig. 2d, the detection module includes a hysteresis comparator and a pull-down resistor Rsn, a first input terminal of the hysteresis comparator is coupled to a preset reference voltage VREF, in one embodiment, the preset reference voltage VREF is zero, a second input terminal of the hysteresis comparator is coupled to a first terminal of the pull-down resistor Rsn and a detection signal SWA of a control terminal of the second power switch MA or the normally-on switch MJ, a second terminal of the pull-down resistor Rsn is coupled to the preset reference voltage VREF or zero voltage, after the demagnetization of the transformer TS is completed, an oscillation signal of a second terminal of the auxiliary winding La is coupled to a control terminal of the second power switch MA or the normally-on switch MJ through a parasitic transcapacitive Cdg between the first terminal and the control terminal of the second power switch MA or the normally-on switch MJ, when the voltage of the detection signal SWA of the second input terminal of the hysteresis comparator is higher than the voltage of the first input terminal (at this time, the second input terminal corresponds to the first input terminal of the hysteresis comparator), and the output signal of the hysteresis comparator corresponds to the reverse phase of the hysteresis comparator xc after the demagnetization of the transformer TS is completed. In one embodiment, the demagnetization signal ZXC changes from low to high, indicating that the demagnetization of the transformer TS is finished.

In one embodiment, as shown in fig. 1a, before the primary winding Lp of the transformer TS starts to charge, the second power switch MA of the auxiliary power supply 110 is first turned on for a part or all of a pulse time, so that the current flowing through the second power switch MA flows through the auxiliary winding La to charge the power supply capacitor CP, the current of the auxiliary winding La is coupled to the primary winding Lp of the transformer TS through the coupling relationship of the transformer TS, so that the energy on the parasitic capacitor Coss of the first power switch MP is transferred to the primary winding Lp, so that the voltage across the first power switch MP is reduced from the first potential when the first power switch MP is turned off to the second potential when the first power switch MP is turned on again, so that the primary winding Lp starts to charge again, and the switching loss of the first power supply system 11 is reduced.

In one embodiment, the auxiliary winding La and the main winding Lp have the same-name ends at the same 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 through the auxiliary winding La to charge the power supply capacitor CP, and through a coupling relationship between the main winding Lp and the auxiliary winding La of the transformer TS, the voltage across Vds of 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, and then 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 auxiliary winding La and the main winding Lp have the same-name ends at opposite 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 through the auxiliary winding La to charge the power supply capacitor CP, and a voltage across Vds of the two ends 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 TS; 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 a second aspect, the present invention provides a power supply system, fig. 1a shows a simplified block diagram of a first power supply system 11, including an auxiliary power supply 110 according to the first aspect, and further including an input capacitor CIN, an output capacitor CO, a control module, and a first power stage 100; the first power stage 100 at least comprises a main stage winding Lp of a transformer TS, a first power switch MP and a follow current module 121, wherein a first control signal GP output by the control module is coupled to a control end of the first power switch MP to control the on and off of the first power switch MP; the second control signal GA output by the control module is coupled with the control end of the second power switch MP through the auxiliary module and controls the on and off of the second power switch MA; the connection between the first power stage 100 and the input capacitor CIN and the output capacitor CO can be combined to form any 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 one embodiment, as shown in fig. 1a, the first power supply system 11 further includes a driving chip, and the driving chip includes at least an auxiliary module and a control module.

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 voltage VAC, and an input capacitor CIN is coupled to an output terminal of the rectifier bridge to bypass the high frequency signal.

In one embodiment, the input voltage VIN of the first power system 11 is a dc voltage of a battery, and the input capacitor CIN is coupled to the input voltage VIN for bypassing high frequency noise.

In one embodiment, the freewheel module 121 is comprised of diodes, and the first power stage 100 including the diodes constitutes a non-synchronous rectification structure.

In one embodiment, the freewheel module 121 is composed of a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), and the first power stage 100 including the field effect transistor constitutes a synchronous rectification structure.

In one embodiment, as shown in fig. 1b, the second power supply system 12 belongs to a step-down power supply system, the main winding Lp and the auxiliary winding La of the transformer TS of the second power supply system 12 have identical-name terminals at the same position, the second power supply system 12 includes an input capacitor CIN, an output capacitor CO coupled in parallel to a load, an auxiliary power supply 110, a control module, and a second power stage 120, and the second power stage 120 includes the main winding Lp, the freewheel module 121, and the 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 main stage winding Lp is coupled with 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, the first end of the auxiliary winding La is coupled with the common node LX of the main-stage winding Lp of the transformer TS and the first power switch MP, and the second end of the auxiliary winding La is coupled with the first port P1 of the auxiliary module after passing through the diode D1. 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, 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 output by the control module controls the on and off of the first power switch MP.

In one embodiment, as shown in fig. 1b, 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 the voltage drop on the main winding Lp is approximately VIN-VO (neglecting the conduction voltage drop of the first power switch MP), and when the turns ratio of the main winding Lp and the auxiliary winding La is Np/na=npa through the coupling relation of the transformer TS, the voltage drop on the auxiliary winding La is also kept to be (VIN-VO)/Npa or approximately equal to (VIN-VO)/Npa; during charging of the main stage winding Lp, the voltage at the first end of the auxiliary winding La is approximately zero, so that the voltage at the second end of the auxiliary winding La is approximately- (VIN-VO)/Npa, and the diode D1 is turned off in reverse bias; during the turn-off period of the first power switch MP, the load voltage VO on the output capacitor CO discharges the main stage winding Lp, and at this time, the voltage drop on the main stage winding Lp is approximately-VO, and the voltage drop on the auxiliary winding La is also maintained to be-VO/Npa or approximately equal to-VO/Npa through the coupling relationship of the transformer TS; during discharge of the primary winding Lp, the voltage at the first end of the auxiliary winding La is approximately VIN, and the voltage at the second end of the auxiliary winding La is vin+vo/Npa, so that during discharge of the transformer TS, the auxiliary module can take power from the second end of the auxiliary winding La to supply the power supply voltage VCC to the control module. After the demagnetization of the main winding Lp is finished, the parasitic capacitance Coss of the first end of the main winding Lp and the first power switch MP generates LC resonance, the potential of the non-homonymous end of the main winding Lp starts to decrease from VIN, the potential of the non-homonymous end of the auxiliary winding La also synchronously decreases through the coupling relation of the transformer TS, and through the coupling action of the parasitic transcapacitive Cdg between the first end and the control end of the second power switch MA or the normally-on switch tube MJ, as shown in fig. 2b and 2c, the oscillation signal of the non-homonymous end of the auxiliary winding La is coupled to the control end of the second power switch MA or the normally-on switch tube MJ to generate a detection signal SWA, and during the demagnetization of the main winding Lp, the detection signal SWA of the control end of the second power switch MA or the normally-on switch tube MJ is compared with a preset reference voltage VREF by the detection module to output a demagnetization signal ZXC representing the completion of the demagnetization of the transformer TS.

In one embodiment, in combination with the waveform diagram shown in fig. 3a, before the primary winding Lp of the transformer TS starts to charge, the secondary power supply 110 of the second power supply system 12 is led to a part or all of a pulse time T13 by the secondary power switch MA, so that the current flowing through the secondary power switch MA flows through the secondary winding La to charge the power supply capacitor CP to form an auxiliary winding current Ia, the auxiliary winding current Ia is coupled to the primary winding Lp by the coupling action of the transformer TS to generate a primary winding current Ip with opposite directions, and the primary winding current Ip and the auxiliary winding current Ia reduce the voltage across Vds across the primary power switch MP connected in series with the primary winding Lp from a first potential when the primary power switch MP is turned off to a lower second potential (the auxiliary winding current Ia and the primary winding current Ip draw current from the common node LX at the same time), so that the switching loss of the primary power switch MP is lower. After the auxiliary winding current Ia becomes zero, the voltage across the first power switch MP will not decrease any more, i.e. the voltage across the first port P1 of the auxiliary module will not decrease any more when the port voltage VP1 of the first port P1 can not decrease any more.

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 demagnetizing signal ZXC of the transformer TS; in one embodiment, the T1 time point is generated in response to one trough of the voltage across Vds of the first power switch MP (or the first trough or the nth trough), and after the demagnetization of the transformer TS is finished, LC resonance occurs between the main winding Lp and the parasitic capacitance Coss of the first end of the first power switch MP, and a plurality of troughs are generated on the voltage across Vds of the first power switch MP; in one embodiment, the T1 time point is generated in response to a pulse width modulated signal (PWM signal) of the power supply system.

In the waveform diagram shown in fig. 3a, the time point T3 corresponds to the on time point of the first power switch MP, and the period between the time point T1 and the time point T3 is the pulse time T13 when the second power switch MA is turned on before the first power switch MP.

In the waveform diagram shown in fig. 3a, the time point T3 is the off time point of the second power switch MA and is also the on time point of the first power switch MP, and 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, which corresponds to that 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, which corresponds to that T23 is the dead time of the first power switch MP and the second power switch MA.

In one embodiment, as shown in fig. 1c for the third power supply system 13, the third power supply system 13 differs from the second power supply system 12 in that the primary winding Lp and the auxiliary winding La of the transformer TS of the third power supply system 13 have opposite identical ends, which also results in a difference in the operation modes of the third power supply system 13 and the second power supply system 12.

As shown in fig. 1c, 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 across the main winding Lp is approximately VIN-VO (neglecting the on-voltage drop of the first power switch MP), and by the coupling relationship of the transformer TS, when the turns ratio of the main winding Lp and the auxiliary winding La is Np/na=npa, the voltage drop across the auxiliary winding La is also kept to be- (VIN-VO)/Npa or approximately equal to- (VIN-VO)/Npa; during charging of the main stage winding Lp, the voltage at the first end of the auxiliary winding La is approximately zero, so the voltage at the second end of the auxiliary winding La is approximately (VIN-VO)/Npa; during the turn-off period of the first power switch MP, the load voltage VO on the output capacitor CO discharges the main stage winding Lp, and at this time, the voltage drop on the main stage winding Lp is approximately-VO, and the voltage drop on the auxiliary winding La is also kept at VO/Npa or approximately equal to VO/Npa through the coupling relationship of the transformer TS; during discharge of the main winding Lp, the voltage at the first end of the auxiliary winding La is approximately VIN, and the voltage at the second end of the auxiliary winding La is VIN-VO/Npa, so that during both charging and discharging of the transformer TS, the auxiliary module can take power from the second end of the auxiliary winding La to supply the supply voltage VCC to the control module. After the demagnetization of the main winding Lp is finished, the parasitic capacitance Coss of the first end of the main winding Lp and the first power switch MP generates LC resonance, the potential of the non-homonymous end of the main winding Lp starts to decrease from VIN, the potential of the non-homonymous end of the auxiliary winding La also synchronously increases through the coupling relation of the transformer TS, and through the coupling action of the parasitic transcapacitive Cdg between the first end and the control end of the second power switch MA or the normally-on switch tube MJ, as shown in fig. 2b and 2c, the oscillation signal of the non-homonymous end of the auxiliary winding La is coupled to the control end of the second power switch MA or the normally-on switch tube MJ to generate a detection signal SWA, and during the demagnetization of the main winding Lp, the detection signal SWA of the control end of the second power switch MA or the normally-on switch tube MJ is compared with a preset reference voltage VREF by the detection module to output a demagnetization signal ZXC representing the completion of the demagnetization of the transformer TS.

Combining the third power supply system shown in fig. 1c and the waveform diagram shown in fig. 3b, the auxiliary winding La of the transformer TS and the main winding Lp 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 power supply 110 is enabled to conduct for the first period T12 to charge the auxiliary winding La, current flows through the auxiliary winding La to charge the supply capacitor CP, the auxiliary winding current Ia flowing through the auxiliary winding La is coupled to the main winding Lp through the coupling relation of the transformer TS, the main winding current Ip with the same direction is generated, the cross-voltage Vds at both ends of the first power switch MP rises to the first potential (neglecting the on-voltage drop on the first power switch MP 121), in the schematic diagram shown in fig. 3b, the second control signal GA is enabled to be high level in the first period T12 of the pulse time T13, the second power switch MA is enabled to conduct for the first period T12, current flows through the auxiliary winding La is enabled to charge the power capacitor CP, the current flows through the auxiliary winding La and the auxiliary winding La with the same-direction of the same-name current flows, and the main winding current is generated by coupling current flows through the main winding with the first power switch winding has the same-name; 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, 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 TS, 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 demagnetizing signal ZXC in which the demagnetization of the transformer TS is completed; 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 diagram 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 for the second power switch MA to be turned on, 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 one embodiment, as shown in fig. 1d, the fourth power supply system 14 belongs to a step-up and step-down power supply system, and includes an input capacitor CIN, an output capacitor CO coupled in parallel to a load, an auxiliary power supply 110, a control module, and a fourth power stage 140, where the fourth power stage 140 includes a main stage winding Lp, a freewheel module 121, and a first power switch MP; the first end of the output capacitor CO is coupled with the first end of the input capacitor CIN and the first end of the main stage winding Lp; a second end of the input capacitor CIN is coupled to ground, and a second end of the output capacitor CO is coupled to a second end of the freewheel module 121; the first end of the auxiliary winding La is coupled to the main stage winding Lp of the transformer TS and the common node LX of the first power switch MP, and the second end of the auxiliary winding La is coupled to the first port P1 of the auxiliary module through a diode D1. A second end of the main stage winding Lp is coupled with a first end of the first power switch MP and a 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, 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 output by the control module controls the on and off of the first power switch MP.

The fourth power supply system 14 is different from the second power supply system 12 in that the fourth power supply system 14 belongs to a step-up and step-down power supply system, and is mainly characterized in that the output capacitance and the load position of the fourth power supply system 14 are different; the principle of the auxiliary power supply 110 of the fourth power supply system 14 supplying power to the outside at the output power supply voltage VCC, or the principle of the auxiliary power supply 110 of the fourth power supply system 14 detecting the demagnetizing state of the transformer TS is completely similar to that of the second power supply system 12 and the third power supply system 13, and specific reference may be made to the analysis of the second power supply system 12 (the auxiliary winding La and the main winding Lp of the transformer TS have the same-name ends at the same positions), and the analysis of the third power supply system 13 (the auxiliary winding La and the main winding Lp of the transformer TS have the same-name ends at opposite positions), and the description will not be repeated.

In one embodiment, as shown in fig. 1e, the fifth power supply system 15 belongs to a boost power supply system, and includes an input capacitor CIN, an output capacitor CO coupled in parallel with a load, an auxiliary power supply 110, a control module, and a fifth power stage 150, where the fifth power stage 150 includes a main stage winding Lp, a freewheel module 121, and a first power switch MP; a first end of the output capacitor CO is coupled to the second end of the freewheel module 121, a second end of the output capacitor CO is coupled to ground, and a first end of the input capacitor CIN is coupled to a first end of the main stage winding Lp; the second terminal of the input capacitor CIN is coupled with the ground; the first end of the auxiliary winding La is coupled to the main stage winding Lp of the transformer TS and the common node LX of the first power switch MP, and the second end of the auxiliary winding La is coupled to the first port P1 of the auxiliary module through a diode D1. A second end of the main stage winding Lp is coupled with a first end of the first power switch MP and a 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, the second end of the first power switch MP is grounded, or is grounded after passing through a current detection resistor, the first control signal GP output by the control module controls the on and off of the first power switch MP, and the second control signal GA output by the control module controls the on and off of the second power switch MA.

The fifth power supply system 15 differs from the second power supply system 12 in that the fifth power supply system 15 belongs to a booster power supply system; the principle of the auxiliary power supply 110 of the fifth power supply system 15 supplying power to the outside at the output power supply voltage VCC, or the principle of the auxiliary power supply 110 of the fifth power supply system 15 detecting the demagnetizing state of the transformer TS is completely similar to that of the second power supply system 12 and the third power supply system 13, and specific reference may be made to the analysis of the second power supply system 12 (the auxiliary winding La and the main winding Lp of the transformer TS have the same-name ends at the same positions), and the analysis of the third power supply system 13 (the auxiliary winding La and the main winding Lp of the transformer TS have the same-name ends at opposite positions), and the description will not be repeated.

In one embodiment, as shown in fig. 1f, the sixth power system 16 belongs to a flyback power system, and includes an input capacitor CIN, an output capacitor CO coupled in parallel with a load, an auxiliary power supply 110, a control module, and a sixth power stage 160, where the sixth power stage 160 includes a primary winding Lp, a secondary winding Ls, a freewheel module 121, and a first power switch MP; the first end of the auxiliary winding La is coupled with the common node LX of the main winding Lp of the transformer TS and the first power switch MP, the second end of the auxiliary winding La is coupled with the first port P1 of the auxiliary module through a diode, the homonymous end of the main winding Lp is coupled with the first end of the input capacitor CIN, the homonymous end of the main winding Lp is coupled with the first end of the first power switch MP, the second end of the first power switch MP is grounded, or grounded after passing through a current detection resistor, the homonymous end of the secondary winding Ls is coupled with the first end of the current detection module 121, the second end of the follow current module 121 is coupled with the first end of the output capacitor CO, and the second end of the output capacitor CO is coupled with the homonymous end of the secondary winding Ls; or the non-homonymous end of the secondary winding Ls is coupled with the first end of the output capacitor CO, the second end of the output capacitor CO is coupled with the first end of the follow current module 121, and the second end of the follow current module 121 is coupled with the homonymous end of the secondary winding Ls; the first control signal GP output by the control module controls the on and off of the first power switch MP, and the second control signal GA output by the control module controls the on and off of the second power switch MA.

The difference between the sixth power supply system 16 and the second power supply system 12 is that the sixth power supply system 16 belongs to a flyback power supply system; the principle of the auxiliary power supply 110 of the sixth power supply system 16 outputting the power supply voltage VCC to externally supply power, or the principle of the auxiliary power supply 110 of the sixth power supply system 16 detecting the demagnetizing state of the transformer TS is entirely similar to that of the second power supply system 12 and the third power supply system 13, and specific reference may be made to the analysis of the second power supply system 12 (the auxiliary winding La and the main winding Lp of the transformer TS have the same-name ends in the same positions), and the analysis of the third power supply system 13 (the auxiliary winding La and the main winding Lp of the transformer TS have the same-name ends in opposite positions), and the description will not be repeated.

As can be seen from the above embodiments, the connection relation between the first power stage 100 and the input capacitor CIN and the output capacitor CO can be combined to form any 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, the invention also provides a power supply arrangement comprising any of the power supply systems of the second aspect.

From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

The auxiliary power supply provided by the invention has the advantages that the auxiliary winding for reducing the switching loss of the power supply system is multiplexed, and the auxiliary winding can bear the high voltage of the bus to provide power for the driving chip of the whole power supply system; and the detection of the demagnetizing state of the transformer is realized through the auxiliary power supply, so that the cost of the power supply system is reduced.

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 invention 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 invention. 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

1. An auxiliary power supply for use in a power supply system having a transformer and a first power switch, the transformer having at least an auxiliary winding and a main winding, the main winding being coupled in series with the first power switch, the auxiliary power supply comprising:

the magnetic induction module further comprises a diode, and the diode is provided with an anode and a cathode, wherein the anode is coupled with the first end of the magnetic induction module, the cathode is coupled with the first end of the auxiliary winding, and the second end of the auxiliary winding is coupled with the second end of the magnetic induction module; or (b)

The magnetic induction module further comprises a diode, wherein the diode is provided with an anode and a cathode, the anode is coupled with the second end of the auxiliary winding, the cathode is coupled with the second end of the magnetic induction module, and the first end of the auxiliary winding is coupled with the first end of the magnetic induction module;

2. The auxiliary power supply of claim 1 wherein the auxiliary module has at least three ports, a first port coupled to the second end of the magnetically sensitive module, a second port coupled to a second control signal, the second control signal controlling the state of the second power switch, a third port providing an electrical voltage to externally power the power supply; or (b)

3. The auxiliary power supply of claim 2, wherein the auxiliary module comprises a second power switch, a first end of the second power switch is coupled to a first port of the auxiliary module, a control end of the second power switch is coupled to a second port of the auxiliary module, a second end of the second power switch is coupled to a supply capacitor and a third port of the auxiliary module, and the third port outputs a supply voltage to supply power to the outside; or (b)

4. The auxiliary power supply of claim 1 wherein the second power switch of the auxiliary power supply is turned on for a portion or all of a pulse time before the primary winding of the transformer begins to charge, causing current flowing through the second power switch to flow through the auxiliary winding to charge the supply capacitor.

5. The auxiliary power supply according to claim 4, wherein the auxiliary winding and the main winding have the same-name ends at the same 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, the current flows through the auxiliary winding to charge the power supply capacitor, 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)

6. A power supply system comprising at least the auxiliary power supply of any one of claims 1 to 5, wherein the power supply system further comprises an input capacitor, an output capacitor, a control module and a power stage; the power stage at least comprises a main stage winding of the transformer, a first power switch and a follow current module, wherein a first control signal output by the control module is coupled with a control end of the first power switch 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 through the auxiliary module to control the on and off of the second power switch; the connection relation between the power level and the input capacitor and the output capacitor can be combined to form any one of a buck power supply system, a boost power supply system, a flyback power supply system and a boost power supply system.

7. The power system of claim 6, wherein the control module controls the second power switch in the auxiliary power supply 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 to charge the supply capacitor.

8. The power supply system according to claim 7, wherein the auxiliary winding and the main winding of the transformer of the power supply system have the same-name ends at the same 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, and the current flows through the auxiliary winding to charge the power supply capacitor, and 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 potential lower than the first potential when the first power switch is turned off, 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)

9. A power supply arrangement comprising the power supply system of any one of claims 6 to 8.