WO2017000668A1

WO2017000668A1 - Power supply circuit and method of auxiliary power supply

Info

Publication number: WO2017000668A1
Application number: PCT/CN2016/081443
Authority: WO
Inventors: 欧阳艳红; 曹青; 郑周锋
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-07-01
Filing date: 2016-05-09
Publication date: 2017-01-05
Also published as: CN106329968B; CN106329968A

Abstract

A power supply circuit and method of an auxiliary power supply. The power supply circuit of the auxiliary power supply comprises a snubber circuit and an auxiliary power supply switch converter. The auxiliary power supply switch converter draws electricity from a snubbing capacitor (C) in the snubber circuit connected to a winding of an inductor or a transformer (T1, T2), stabilizes a voltage via voltage transformation, and then supplies power to a control circuit. A primary switch (Qf) of the auxiliary power supply switch converter in a steady state is controlled by at least one driving timing signal (Qf_dr), and the driving timing signal is associated with control timing signals (VDS_Q2, VDS_Q4) in a main power topology. The power supply circuit and the method address the problems of a low power supply efficiency and a large circuit volume, simplify the winding design of a transformer or an inductor, and facilitate copper loss reduction in a transformer or an inductor with a limited winding volume.

Description

Power supply circuit and method for auxiliary power supply

Technical field

The present invention relates to the field of electronic technologies, and in particular, to a power supply circuit and method for an auxiliary power source.

Background technique

In the field of switching power supplies, the commonly used auxiliary power supply mode, in addition to the independent auxiliary power supply and the separate linear power supply, the most widely used is the winding power supply.

In the isolated topology, the power supply for the secondary side control circuit is generally divided into two parts: the starting power supply and the steady state power supply. At present, the more commonly used startup power supply and steady state power supply are shown in Figure 1 and Box 3 of Figure 1. Box 1 is to start the power supply. After adding additional windings to the transformer windings, and then rectifying them through the diodes Dc and Cc, and then linearly regulating the voltage regulators RL, the Zener diodes DL, the power transistors QL and the voltage regulators CL, Power is supplied to the control circuit section; block 3 is a steady-state power supply. By adding additional windings to the inductor windings, after diode Dw and capacitor Cw are regulated, a stable voltage is obtained which is proportional to the output voltage and is proportional to the output winding. Control circuit part.

The starting power supply shown in block 1 of Figure 1, the voltage on the capacitor Cc can be established within several switching cycles. The voltage on the Cc is a stable voltage with an analogy relationship with the input voltage, which can achieve the purpose of fast power supply. The drawback of the power supply is that the voltage on the Cc is in a turn-to-turn relationship with the input voltage, which varies with the input voltage, and the power supply efficiency is low at a wide input voltage. Therefore, after the boot is completed, the secondary power supply will switch to the steady state power supply shown in Box 3.

The steady-state power supply shown in block 3, the voltage on Cw is basically established following the establishment of the output voltage. In order to limit the inrush current in the main circuit, the output voltage is slowly rising, so the voltage on Cw is also slowly rising, and the power supply speed is slow; In the case of full load at the output end, the voltage on Cw will fluctuate up and down; in the case of no-load large-capacity shutdown, the voltage on Cw will increase sharply and even exceed the control due to nowhere on the inductor. The circuit part of the chip can withstand the voltage range, which may cause damage to some parts of the control circuit, which seriously affects the reliability of the power supply.

Box 2 in Figure 1 shows the commonly used RCD (including resistor, capacitor and diode) absorbing circuits. The energy on the snubber C is generally consumed by the discharge resistor R. This method reduces the power efficiency and requires the absorbing resistor. The power consumption requirement is large, and the absorption resistor is bulky. Generally, a large package resistance is required to be placed, which affects the realization of the high power density of the power supply and the miniaturization of the volume.

Summary of the invention

The embodiment of the invention provides a power supply circuit and method for an auxiliary power source, which utilizes the energy of the absorption capacitor to supply power to the control circuit, and the control circuit simultaneously discharges the absorption capacitor, which is beneficial to improving the power supply efficiency and reducing the circuit volume.

In order to achieve at least the above object, an embodiment of the present invention provides a power supply circuit for an auxiliary power supply, including: an absorbing circuit and an auxiliary power switching converter, wherein the auxiliary power switching converter takes power from an absorbing capacitor of the absorbing circuit. Suck The receiving circuit is connected to the transformer or the inductor winding; the auxiliary power switching converter is regulated by voltage conversion, and supplies power to the control circuit; the main switch of the auxiliary power switching converter is controlled by at least one driving timing signal, and The drive timing signal is associated with a control timing signal of the main power topology.

In one embodiment of the invention, the control circuit discharges the absorption capacitance of the absorption circuit.

In one embodiment of the invention, the absorbing circuit extracting energy from the main circuit includes the absorbing circuit taking energy from the transformer winding or the inductive winding.

In one embodiment of the invention, the absorption circuit comprises: a capacitor and a diode; or a capacitor, a diode, and a discharge resistor that is increased according to a circuit requirement; the diode is connected to a transformer winding or an inductor in the main circuit.

The main switch of the auxiliary power switch converter at steady state is controlled by the at least one drive timing signal comprising: a drive timing signal of the auxiliary power switch converter and at least one of a transformer end or a single end ground signal in the main power topology The timing of the signals is consistent.

In an embodiment of the present invention, the main switch in the auxiliary power switching converter is controlled by the at least one driving timing signal, and the driving timing signal of the auxiliary power switching converter is the timing of the transformer to the ground The superposition of signals.

In an embodiment of the present invention, when the power supply voltage is lower than the preset voltage value during the startup of the auxiliary power supply to the control circuit, the driving timing signal in the auxiliary power switching converter is always high.

In one embodiment of the invention, the input terminals of the auxiliary power switching converter are respectively connected from one end of a capacitor in the snubber circuit.

In an embodiment of the present invention, the auxiliary power switching converter includes: a driving signal source circuit, a main power MOS transistor, a filter inductor, a freewheeling diode, and an auxiliary power source capacitor;

The driving signal source circuit provides a driving timing signal to the auxiliary power converter main power MOS transistor; the auxiliary power converter main power MOS transistor drain is connected to the first end of the capacitor in the absorbing circuit; the auxiliary power source The main power MOS tube source stage of the converter is connected to the first end of the filter inductor; the main power MOS tube source stage is connected to the cathode of the freewheeling diode; the anode of the freewheeling diode is connected to the ground; the second end of the filter inductor The first end of the auxiliary power supply capacitor is connected; the second end of the auxiliary power supply capacitor is connected to the reference ground.

In order to solve at least the above technical problem, the embodiment of the present invention further provides a power supply method for an auxiliary power source, including:

The auxiliary power switching converter takes energy from the snubber capacitance in the snubber circuit connected to the winding of the transformer;

The auxiliary power switching converter supplies the energy to the control circuit after voltage regulation, and the driving signal timing of the auxiliary power switching converter is associated with the main topology transformer to ground timing signal.

The beneficial effects of the embodiments of the present invention are:

An embodiment of the present invention provides a power supply circuit and method for an auxiliary power supply, the power supply circuit of the auxiliary power supply includes an absorption circuit and an auxiliary power switching converter, and the absorption circuit obtains energy from the main circuit for providing the control circuit Place The auxiliary power switching converter is configured to perform conversion processing on the energy extracted from the absorbing circuit; supply the voltage after the voltage stabilization processing to the control circuit; and drive timing signals of the auxiliary power switching converter Both ends of the main power topology main transformer or single-ended to ground timing signals are associated. The embodiment of the invention simplifies the winding design of the transformer and the inductor, reduces the copper loss of the transformer and the inductor in the limited winding volume, and improves the power supply efficiency; at the same time, the auxiliary power supply of the control circuit part discharges the absorption capacitor, and the absorption capacitor can be discharged without discharging. Resisting or reducing the number of discharge resistors saves energy, which is beneficial to improve power supply efficiency and reduce power supply volume. The auxiliary power supply mode is suitable for applications with a wide input voltage range, high power supply efficiency, fast power supply, and stable power supply.

DRAWINGS

The drawings described herein are intended to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing:

Figure 1 is a schematic diagram of a common secondary side power supply and absorption mode;

2 is a schematic diagram of an auxiliary power supply mode for simultaneously discharging an absorption capacitor;

Figure 3 is a timing diagram of VDD boot-to-state Qf_dr drive;

4 is a schematic diagram of a specific implementation circuit of Qf_dr;

Figure 5 is a diagram showing the use of full-bridge rectification on the secondary side, the absorption winding mode of the inductor winding, and the drive timing diagram;

Figure 6 is a diagram showing the use of full-wave rectification on the secondary side, the absorption and extraction modes and the drive timing diagram at both ends of the transformer winding;

Figure 7 is a diagram showing the use of full-wave rectification on the secondary side, the absorption winding mode of the inductor winding, and the drive timing diagram;

Figure 8 is a diagram showing the absorption and power take-off mode and driving timing of the single-ended transformer winding;

9 is a schematic diagram of the power-on mode Qf startup and steady-state driving sequence of the single-ended transformer in FIG. 8;

Figure 10 is a schematic diagram of the auxiliary power supply voltage division power supply mode.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

It is to be understood that the terms "first", "second" and the like in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a particular order or order.

The embodiment of the present invention mainly provides a power supply circuit for an auxiliary power supply, comprising: an absorption circuit and an auxiliary power switching converter, wherein the auxiliary power switching converter takes power from an absorption capacitor of the absorption circuit, and the absorption circuit and the absorption circuit Transforming or inductive winding connection; the auxiliary power switching converter is regulated by voltage conversion to supply power to the control circuit; the main switch of the auxiliary power switching converter at steady state is controlled by at least one driving timing signal, and the driving Timing signal and main The control timing signals of the power topology are associated. The embodiments of the present invention are described below by way of specific embodiments.

Embodiment 1:

As shown in Figure 2, the main topology secondary side uses a full-bridge rectifier circuit, the absorption diodes Dc1, Dc2 are respectively connected to the two ends of the secondary transformer winding, together with the absorption capacitor C constitutes the absorption circuit of the Q2 and Q4 power tubes; the auxiliary power switch The main switch tubes Qf, Lf, Df and Cf form a BUCK converter. The BUCK converter takes power from the snubber capacitor C. After the conversion, the output voltage VDD is supplied to the control circuit. After the output voltage is completed, the driving signal when the main power topology duty ratio is stable is driven as shown in block B of FIG. 2, which is a signal superimposed by the VDS signal of Q2 and the VDS signal of Q4. The principle of utilization is that the sum of the VDS signal of Q2 and the VDS signal of Q4 is the duty ratio of the main topology. Under the circuit topology with stable output voltage, the VDD voltage is basically the same as the main topology output voltage, and is also a stable output. of.

Since the duty cycle of the main topology is slowly established at boot time, we need to quickly establish VDD and supply power to the control circuit. During the boot process, the power tube Q2 and Q4 stress are the largest, and the snubber capacitor is required. C discharge as much as possible. Based on two considerations, the relationship between the driving timing of Qf and the VDD settling time is shown in Fig. 3. When VDD is established from 0, Qf_dr is always high when VDD is less than VDD_min; Qf_dr follows the superposition of VDS_Q2 and VDS_Q4 when VDD is greater than VDD_min; Qf_dr is high as long as VDD is less than VDD_min.

One of the specific implementation circuits of Qf_dr is shown in Figure 4. Dc1, Dc2 and capacitor C are the absorption circuits of the power tube, Dz is the controllable precision voltage regulator source TL431, and VDD is divided into Rz by Rsw1 and Rsw2. The R terminal is used to set a VDD_min value. When the VDD divider is lower than the internal regulation value of TL431, the K terminal of Dz is high impedance. At this time, Qs is turned on and Qf_dr is set high. When the VDD divider is higher than the internal regulation value of TL431, the K terminal of Dz is low impedance. At this time, Qs is turned off, and Qf_dr is determined by the superposition of VDS_Q2 and VDS_Q4 signals. 4 is only one of the circuit diagrams for implementing the Qf_dr signal, and any auxiliary power converter main power tube is driven by a simple conversion or other means in the art to obtain a Qf_dr timing signal similar to that shown in FIG. The method of taking power from the absorbing capacitor and supplying power to the control circuit belongs to the protection scope of the present invention.

In Figure 2, the snubber capacitor is powered by Dc1 and Dc2 simultaneously, but the power supply mode of the auxiliary power supply is realized by any one of the diodes. The auxiliary power conversion mode shown in Figure A of Figure 2 is applied, as shown in Figure 3. The manner in which the timing diagram completes the auxiliary power supply is within the scope of the present invention.

In the main topology given in Figure 2, the secondary side uses the full-bridge synchronous rectification mode. The power transistors Q1, Q2, Q3, and Q4 are power MOSFETs, and the secondary side is diodes (Q1, Q2, Q3, and Q4). For the diode) rectification or semi-synchronous (Q1, Q3 is the diode, Q2, Q4 is the power switch) rectification, using the auxiliary power conversion mode shown in Figure A, Figure A, through the timing diagram shown in Figure 3 to complete the auxiliary power supply The manner of the present invention falls within the scope of protection of the present invention.

Or, in the main topology shown in Figure 2, the auxiliary power conversion mode shown in block A, if VDD is only half of the main power topology output voltage, by changing Qf_dr in Figure 3 at VDD steady state only by VDS_Q2 or VDS_Q4 One of the signals can be generated, that is, only one of Dq2 or Dq4 is used in the schematic diagram of FIG. 4. At this time, the steady-state voltage of VDD in FIG. 2 is basically half of the output voltage of the main topology, and this case also falls within the protection range of the present invention. within.

Embodiment 2:

As shown in FIG. 5, the secondary side is full-bridge rectification, the diode Dc1 and the capacitor C constitute an absorption circuit of Q2 and Q4, and the auxiliary power switching converter takes power from the absorption capacitor C. The driving timing of the switching signal Qf_dr of the main power tube of the auxiliary power switching converter is shown in FIG. 3 when the power is turned on, and the specific implementation process is as described in the first embodiment; in the steady state, as shown by the dotted line in FIG. The VDS_Q2 and the VDS_Q4 are superimposed. The specific implementation process is as described in the first embodiment. At this time, the VDD steady-state power supply voltage is substantially the same as the main topology output voltage.

In the main topology given in Figure 5, the secondary side uses the full-wave synchronous rectification mode. The power transistors Q1, Q2, Q3, and Q4 are power MOSFETs, and the secondary side is diodes (Q1, Q2, Q3, and Q4). For the diode) rectification or semi-synchronous (Q1, Q3 is the diode, Q2, Q4 is the power switch) rectification, using the auxiliary power conversion mode shown in Figure A, Figure A, through the timing diagram shown in Figure 3 to complete the auxiliary power supply The manner of the present invention falls within the scope of protection of the present invention.

The main topology shown in Figure 5, the auxiliary power conversion mode shown in Box A, if VDD is only half of the main power topology output voltage, by changing Qf_dr in Figure 3 at VDD steady state only by one of VDS_Q2 or VDS_Q4 Signal generation can be realized, that is, Dq2 or Dq4 in Fig. 4 only uses one of them. At this time, the VDD steady-state voltage in Fig. 5 is basically half of the main topology output voltage, and this case also falls within the protection scope of the present invention. .

Embodiment 3:

As shown in FIG. 6, the secondary side is full-wave rectification, the diodes Dc1, Dc2 and the capacitor C constitute an absorption circuit of Q2 and Q4, and the auxiliary power switching converter takes power from the absorption capacitor C. The driving timing of the switching signal Qf_dr of the main power tube of the auxiliary power switching converter is shown in FIG. 3 when the power is turned on, and the specific implementation process is as described in the first embodiment; in the steady state, as shown by the dotted line in FIG. It is shown that the VDS_Q2 and the VDS_Q4 are superimposed, and the specific implementation process is as described in the first embodiment. At this time, since the voltage on the absorbing capacitor C is twice the center tapped square wave voltage, the VDD steady-state voltage in FIG. 6 is basically twice the main topology output voltage.

In Figure 6, the snubber capacitor is powered by Dc1 and Dc2 simultaneously, but the power supply mode of the auxiliary power supply is realized by any one of the diodes. The auxiliary power conversion mode shown in Figure A of Figure 2 is applied, as shown in Figure 3. The manner in which the timing diagram completes the auxiliary power supply is within the scope of the present invention.

In the main topology given in Figure 6, the secondary side uses the full-wave synchronous rectification method. The power transistors Q2 and Q4 are power MOS tubes, and the secondary side uses diodes (Q2 and Q4 are diodes) for rectification. The auxiliary power conversion mode shown in block A of FIG. 2, the manner of completing the auxiliary power supply by the timing chart shown in FIG. 3, belongs to the protection scope of the present invention.

The main topology shown in Figure 6, the auxiliary power conversion mode shown in Box A, if VDD is only half of the main power topology output voltage, by changing Qf_dr in Figure 3, the VDD steady state is only one of VDS_Q2 or VDS_Q4. Signal generation can be realized, that is, only one of Dq2 or Dq4 is used in the schematic diagram of Fig. 4. At this time, the VDD voltage in Fig. 6 is substantially the same as the main topology output voltage, and this also falls within the protection scope of the present invention.

Embodiment 4:

As shown in Figure 7, the secondary side is full-wave rectification, and the diode Dc1 and the capacitor C form an absorption circuit of Q2 and Q4, which is auxiliary. The power switching converter takes power from the snubber capacitor C. The driving timing of the switching signal Qf_dr of the main power switch of the auxiliary power switching converter is shown in FIG. 3 when the power is turned on, and the specific implementation process is as described in the first embodiment; in the steady state, as shown by the dotted line in FIG. 7 The VDS_Q2 and the VDS_Q4 are superimposed. The specific implementation process is as described in the first embodiment. At this time, the VDD steady-state voltage in FIG. 7 is substantially the same as the main topology output voltage.

In the main topology given in Figure 7, the secondary side uses the full-wave synchronous rectification method. The power transistors Q2 and Q4 are power MOS tubes, and the secondary side uses diodes (Q2 and Q4 are diodes) for rectification. The auxiliary power conversion mode shown in block A of FIG. 2, the manner of completing the auxiliary power supply by the timing chart shown in FIG. 3, belongs to the protection scope of the present invention.

The main topology shown in Figure 7, the auxiliary power conversion mode shown in Box A, if VDD is only half of the main power topology output voltage, by changing Qf_dr in Figure 3, the VDD steady state is only one of VDS_Q2 or VDS_Q4. Signal generation can be realized, that is, Dq2 or Dq4 in Fig. 4 only uses one of them. At this time, the steady-state voltage of VDD in Fig. 7 is basically half of the output voltage of the main topology, and this case also falls within the protection scope of the present invention. .

Embodiment 5:

As shown in FIG. 8, the anode of the absorption diode Dc1 is connected to the junction of the transformer winding and the inductor winding, and is the drain of the freewheeling tube Q2. The cathode of the absorption diode Dc1 is connected to the absorption capacitor C, and the auxiliary power switching converter is taken from the absorption capacitor C. The steady-state driving timing of the Qf is as shown in the dotted line in Figure 8, and only VDS_Q2 is determined.

The VDD boot timing shown in Figure 8 is shown in Figure 9. When VDD starts from 0, Qf_dr is always high when VDD is less than VDD_min; Qf_dr follows VDS_Q2 when VDD is greater than VDD_min; Qf_dr is as long as VDD is less than VDD_min High.

The driving signal Qf_dr of Qf in Fig. 8 can still be realized by using the circuit diagram shown in Fig. 4, as long as the VDS_Q4 signal is removed.

Figure 8 shows the snubber capacitor power and VDD power supply mode. The power transistors Q1 and Q2 are power MOS transistors, and the secondary side uses diodes (Q1 and Q2 diodes) to rectify. The application shown in Figure 8 is applied. The power conversion mode and the manner in which the auxiliary power supply is completed by the timing chart shown in FIG. 9 are all within the protection scope of the present invention. The VDD steady-state voltage in Figure 8 is basically the main topology output voltage.

The main switching tube Qf of the auxiliary power switching converter in the first embodiment, the second, the third, the fourth and the fifth embodiment may be a power MOS tube or a power transistor realized by a simple conversion in the field; the freewheeling diode Df is also It can be a power MOS transistor; as long as the Qf_dr driving sequence described in the embodiment of the present invention is used to complete the power taking from the snubber capacitor and the power supply to the control circuit portion is simple, it belongs to the protection scope of the present invention.

The auxiliary power supply capacitor Cf in the above-mentioned specific embodiments one, two, three, four and five may be a capacitor or a series connection of several capacitors, as shown in FIG. 10, after the capacitor is divided in series, and then in each suitable The voltage point is powered, directly supplied to the control circuit, or after re-regulation, such as LDO, linear regulator, etc., and then supplied to each control circuit. This approach also falls within the scope of the present invention.

In the above specific embodiments 1, 2, 3, 4 and 5, in addition to the auxiliary power supply to the absorbing capacitor during circuit application In addition to the discharge, depending on the specific application, it is also possible to discharge the absorbing capacitor together with the discharge resistor, that is, a simple change to the invention falls within the scope of the present invention.

An embodiment of the present invention further provides a power supply method for an auxiliary power supply, comprising: an auxiliary power switching converter that extracts energy from an absorption capacitor in an absorption circuit connected to a winding of a transformer; the auxiliary power switching converter converts the energy The control circuit is powered by voltage conversion, and the drive signal timing of the auxiliary power switching converter is associated with the main topology transformer to ground timing signal.

Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, by hardware, but in many cases, the former is A better implementation. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, may be embodied in the form of a software product stored in a storage medium (such as ROM/RAM, disk, The optical disc includes a number of instructions for causing a terminal device (which may be a cell phone, a computer, a server, or a network device, etc.) to perform the methods described in various embodiments of the present invention.

It should be noted that each of the above modules may be implemented by software or hardware. For the latter, the foregoing may be implemented by, but not limited to, the foregoing modules are all located in the same processor; or, the modules are located in multiple In the processor.

Embodiments of the present invention also provide a storage medium. Optionally, in the embodiment, the storage medium may be configured to store program code set to perform the following steps:

S1, the auxiliary power switching converter obtains energy from the absorption capacitor in the absorption circuit connected to the winding of the transformer;

S2, the auxiliary power switching converter supplies the energy to the control circuit by voltage conversion, and the driving signal timing of the auxiliary power switching converter is associated with the main topology transformer to ground timing signal.

For example, the specific examples in this embodiment may refer to the examples described in the foregoing embodiments and the optional embodiments, and details are not described herein again.

It will be apparent to those skilled in the art that the various modules or steps of the present invention described above can be implemented by a general-purpose computing device that can be centralized on a single computing device or distributed across a network of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps thereof are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in Within the scope of protection of the present invention.

Industrial applicability

As described above, the power supply circuit and method for an auxiliary power supply provided by the embodiments of the present invention have the following beneficial effects: the embodiment of the present invention simplifies the winding design of the transformer and the inductor, and is advantageous for reducing the transformer and the inductance within the limited winding volume. Copper loss, improve power efficiency; at the same time, the auxiliary power supply of the control circuit part discharges the absorption capacitor. The absorption capacitor can save the electric energy without increasing the discharge resistance or reducing the number of discharge resistors, which is beneficial to improve the power supply efficiency and reduce the power supply volume. The power supply mode is suitable for applications with a wide input voltage range, high power supply efficiency, fast power supply, and stable power supply.

Claims

A power supply circuit for an auxiliary power source, comprising an absorbing circuit and an auxiliary power switching converter, wherein the auxiliary power switching converter takes power from an absorbing capacitor of the absorbing circuit, and the absorbing circuit is connected to a transformer or an inductor winding; The auxiliary power switching converter supplies power to the control circuit after voltage regulation; the main switch of the auxiliary power switching converter is controlled by at least one driving timing signal, and the driving timing signal and the main power topology are controlled. Timing signals are associated.
A power supply circuit for an auxiliary power supply according to claim 1, wherein said control circuit discharges an absorption capacitance of said absorption circuit.
A power supply circuit for an auxiliary power supply according to claim 1, wherein said absorbing circuit comprises: a capacitor and a diode; or a capacitor, a diode, and a discharge resistor that is added according to a circuit; said diode and a transformer winding or inductor in the main circuit connection.
A power supply circuit for an auxiliary power source according to claim 1, wherein said absorbing circuit extracting energy from said main circuit comprises: said absorbing circuit extracting energy from a transformer winding or an inductor winding.
A power supply circuit for an auxiliary power source according to claim 1, wherein said main switch of said auxiliary power switch converter at steady state is controlled by at least one drive timing signal comprising: a drive timing signal of said auxiliary power switch converter and said main The timing of at least one signal of the signal at both ends of the transformer or single-ended to ground in the power topology is consistent.
A power supply circuit for an auxiliary power supply according to claim 1, wherein said main power switch converter is in a steady state when said main switch is controlled by at least one drive timing signal comprising: said auxiliary power switch converter driving timing signal is The superposition of the timing signals of the two ends of the transformer to the ground.
The power supply circuit of the auxiliary power source according to claim 1, wherein in the auxiliary power supply starting process of the power supply to the control circuit, when the power supply voltage is lower than a preset voltage value, the auxiliary power switch converter The drive timing signal is always high.
A power supply circuit for an auxiliary power source according to claim 1, wherein an input terminal of said auxiliary power switching converter is respectively connected from one end of a capacitor in said absorbing circuit.
The power supply circuit of the auxiliary power supply according to any one of claims 1 to 8, wherein the auxiliary power switching converter comprises: a driving signal source circuit, a main power MOS transistor, a filter inductor, a freewheeling diode, and an auxiliary power source capacitor;

The driving signal source circuit provides a driving signal to the main power MOS transistor; the main power MOS transistor drain is connected to the first end of the capacitor in the absorbing circuit; and the main power MOS tube source level is connected to the filter inductor a first end; the main power MOS tube source stage is connected to the cathode of the freewheeling diode; the anode of the freewheeling diode is connected to the reference ground; the second end of the filter inductor is connected to the first end of the auxiliary power supply capacitor; The second end of the power capacitor is connected to the reference ground.
A method of supplying power to an auxiliary power source, comprising:

The auxiliary power switching converter takes energy from the snubber capacitance in the snubber circuit connected to the winding of the transformer;

The auxiliary power switching converter supplies the energy to the control circuit after voltage regulation, and the driving signal timing of the auxiliary power switching converter is associated with the main topology transformer to ground timing signal.