CN116365827A - Power supply circuit and power supply method of flyback converter and flyback converter - Google Patents

Power supply circuit and power supply method of flyback converter and flyback converter Download PDF

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Publication number
CN116365827A
CN116365827A CN202211641633.1A CN202211641633A CN116365827A CN 116365827 A CN116365827 A CN 116365827A CN 202211641633 A CN202211641633 A CN 202211641633A CN 116365827 A CN116365827 A CN 116365827A
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CN
China
Prior art keywords
power supply
control chip
auxiliary winding
supply voltage
switch
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Pending
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CN202211641633.1A
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Chinese (zh)
Inventor
张军明
蒋香华
许祥勇
黄必亮
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Joulwatt Technology Co Ltd
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Joulwatt Technology Co Ltd
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Priority to CN202211641633.1A priority Critical patent/CN116365827A/en
Publication of CN116365827A publication Critical patent/CN116365827A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0006—Arrangements for supplying an adequate voltage to the control circuit of converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H02J7/345—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering using capacitors as storage or buffering devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J2207/50—Charging of capacitors, supercapacitors, ultra-capacitors or double layer capacitors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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

Abstract

The invention provides a power supply circuit and a power supply method of a flyback converter and the flyback converter, wherein the power supply circuit comprises: the first capacitor is connected with the power supply end of the primary side control chip and is used for providing power supply voltage for the primary side control chip; the first switch and the first diode are arranged on a charging path of the auxiliary winding in the transformer to the first capacitor in series, and the first switch is used for connecting or disconnecting the charging path according to a control signal; the detection module is used for detecting the power supply voltage, comparing the power supply voltage with a preset value and generating the control signal according to a comparison result. The stable power supply to the primary side control chip can be realized by a simple circuit structure and a simple control method, and the power consumption is lower.

Description

Power supply circuit and power supply method of flyback converter and flyback converter
Technical Field
The invention relates to the technical field of switching power supplies, in particular to a power supply circuit and a power supply method of a flyback converter and the flyback converter.
Background
The flyback converter start-up phase is typically carried out from the bus voltage V by means of a start-up resistor or JFET (junction field effect transistor) bus The power is taken out, and the bus voltage is the input voltage of the flyback converter; after starting, the auxiliary winding in the transformer is used for normally supplying power to the primary side control chip.
With the advent of PD adapters, the range of output voltages is wider. Because the auxiliary winding and the auxiliary winding in the transformer are used in the same-name mode, the voltage range of the auxiliary winding rectified by the rectifying circuit can change along with the change of output voltage, and the power supply voltage range of a common primary control chip is narrower, so that the mode of directly supplying power by the auxiliary winding is not beneficial to the stable power supply of the primary control chip. To solve this problem, there have been proposed:
1. as shown in fig. 1a, the LDO (low dropout regulator, low dropout linear regulator) 12 is used to convert the wider voltage Vin of the auxiliary winding Na rectified by the rectifying circuit 11 into a stable supply voltage Vcc. However, the power consumption of this power supply method is large, especially when the voltage difference between the input voltage Vin and the output voltage Vcc of the LDO circuit 12 is large. In addition, the LDO circuit 12 has only a linear step-down function, and is not beneficial to the application of a wide-range output voltage due to the lack of a step-up function when the rectified voltage Vin of the auxiliary winding Na is low.
2. As shown in fig. 1b, the auxiliary winding Na is rectified by the rectifying circuit 11 to convert the wider voltage Vin into a stable supply voltage Vcc using the DC-DC converter 13 (including, for example, a boost circuit, buck/boost circuit, buck-boost circuit, etc.). The DC-DC converter 13 can well support a wide range of output applications. Although the use of a DC-DC converter, particularly a boost converter with a boost function, can solve the problems of the former scheme, an inductor, a switching tube and a diode are required for the periphery, and the circuit structure and the control process are complicated.
Accordingly, there is a need to provide an improved solution to overcome the above technical problems in the prior art.
Disclosure of Invention
In order to solve the technical problems, the invention provides a power supply circuit and a power supply method of a flyback converter, and the flyback converter can realize stable power supply to a primary side control chip with a simple circuit structure and a control method and has lower power consumption.
According to a first aspect of the present invention, there is provided a power supply circuit for a flyback converter, the flyback converter comprising: the transformer, main switch tube and primary control chip, power supply circuit is used for the primary control chip provides supply voltage, and this power supply circuit includes:
the first capacitor is connected with the power supply end of the primary side control chip and is used for providing power supply voltage for the primary side control chip;
the first switch and the first diode are arranged on a charging path of the auxiliary winding in the transformer to the first capacitor in series, and the first switch is used for connecting or disconnecting the charging path according to a control signal;
the detection module is used for detecting the power supply voltage, comparing the power supply voltage with a preset value and generating the control signal according to a comparison result.
Optionally, the detection module is configured to control the first switch to be turned on to connect the charging path when the supply voltage is lower than the preset value, or to control the first switch to be turned off to disconnect the charging path when the supply voltage is higher than the preset value.
Optionally, the first switch is arranged between the auxiliary winding and a power supply end of the primary side control chip; or the first switch is arranged between the auxiliary winding and the reference ground.
Optionally, the first switch is any one of a field effect transistor and a bipolar transistor.
Optionally, when the first switch has a parasitic diode, the parasitic diode is reversely disposed on a charging path of the auxiliary winding to the first capacitor.
According to a second aspect of the present invention there is provided a flyback converter comprising:
the transformer comprises a primary winding, a secondary winding and an auxiliary winding;
the main switch tube is connected in series between the primary winding and the voltage input end or the reference ground;
the primary side control chip is used for providing control signals for the main switching tube;
the power supply circuit is used for providing power supply voltage for the primary side control chip.
According to a third aspect of the present invention, there is provided a method of supplying power to a flyback converter, the flyback converter comprising: the power supply method comprises the following steps of:
detecting the power supply voltage of the primary side control chip;
comparing the power supply voltage with a preset value;
and connecting or disconnecting a unidirectional conductive power supply path of the auxiliary winding in the transformer to the primary side control chip according to the comparison result.
Optionally, the connecting or disconnecting the unidirectional conductive power supply path of the auxiliary winding in the transformer to the primary side control chip according to the comparison result includes: and connecting or disconnecting the charging path of the auxiliary winding to the first capacitor according to the comparison result so as to equivalently connect or disconnect the unidirectional conductive power supply path of the auxiliary winding to the primary control chip.
Optionally, the power supply path is connected when the power supply voltage is lower than the preset value; or disconnecting the power supply path when the power supply voltage is higher than the preset value.
The beneficial effects of the invention at least comprise:
according to the embodiment of the invention, the on-off of the charging path of the auxiliary winding to the first capacitor is controlled by detecting and comparing the power supply voltage with the preset value, and the power supply voltage of the primary control chip can be stabilized near the preset value only by presetting the proper output voltage of the auxiliary winding; in the whole process, the charging process of the capacitor is not continuously performed, and an additional inductor is not required to be arranged in the charging process, so that the circuit structure and the control method are simpler, and the circuit power consumption is lower.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.
Drawings
Fig. 1a shows a schematic diagram of a power supply circuit of a flyback converter according to the prior art;
FIG. 1b shows a schematic diagram of a power supply circuit of another prior art flyback converter;
fig. 2 is a schematic diagram showing a structure of a power supply circuit of a flyback converter according to a first embodiment of the present invention;
fig. 3 is a schematic diagram showing a structure of a power supply circuit of a flyback converter according to a second embodiment of the present invention;
fig. 4 shows a schematic flow chart of a power supply method of a flyback converter according to an embodiment of the present invention.
Detailed Description
In order that the invention may be readily understood, a more complete description of the invention will be rendered by reference to the appended drawings. Preferred embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
In the present invention, the technical solution of the present invention will be exemplified by only a common single-tube flyback converter. It should be appreciated that the disclosed solution is also applicable to other types of flyback converters such as active clamp flyback converters, asymmetric half-bridge flyback converters AHB, etc.
As shown in fig. 2 and 3, a flyback converter provided by an embodiment of the present invention includes: the transformer T, the main switching tube Q1, the primary control chip 20 and the power supply circuit 30 comprise a primary winding Np, a secondary winding Ns and an auxiliary winding Na.
Wherein one end of the primary winding Np and the input voltage V of the flyback converter bus The input end is connected with the drain electrode of the main switch tube Q1, the source electrode of the main switch tube Q1 is connected withThe reference ground is connected. The gate of the main switching tube Q1 is connected to the primary side control chip 20. The main switch tube Q1 is connected with the input voltage V by periodical connection and disconnection bus Is transferred from the primary side portion to the secondary side portion of the flyback converter. In some possible embodiments, the main switching transistor Q1 is an NMOS field effect transistor or GAN device. Wherein the input voltage V bus The primary bus voltage of the flyback converter can be obtained by rectifying and filtering an alternating current signal output by an external alternating current source AC through a rectifier bridge 21 and a capacitor Ci.
The secondary side portion of the transducer includes: a rectifying tube (e.g. diode or field effect transistor) D1 and an output capacitance Co. Taking diode D1 as an example, its anode is connected to the secondary winding Ns and its cathode is connected to the output of the flyback converter. The positive pole of output capacitor Co is connected with the output of flyback converter, and the negative pole of output capacitor Co is connected with reference ground. Further, the output end of the flyback converter is connected with a load, and the load receives the electric energy (such as voltage and current) converted by the flyback converter. In some examples, the power converted by the flyback converter is also passed through a filter before reaching the load. In some examples, the filter is a subcomponent of the flyback converter, an external component of the flyback converter, and/or a subcomponent of the load. In any case, the load may perform a function using filtered or unfiltered electrical energy from the flyback converter. Alternatively, the load may include, but is not limited to, a computing device and related components or any other type of electrical device and/or circuitry that receives voltage or current from the flyback converter.
The primary control chip 20 is configured to provide a control signal Vgs1 for the main switching tube Q1 according to the compensation signal Vcomp representing the output voltage Vo to control on and off of the main switching tube Q1, and the specific structure can be understood with reference to the prior art.
The power supply circuit 30 is used for providing a required power supply voltage Vcc for the primary side control chip 20. The power supply circuit 30 further includes: a capacitor C1, a diode D2, a switch K1 and a detection module 31.
The capacitor C1 is connected between the power supply terminal of the primary side control chip 20 and the reference ground, and is configured to provide the power supply voltage Vcc for the primary side control chip 20 according to the voltage between the two terminals.
The switch K1 and the diode D2 are disposed in series on the charging path of the auxiliary winding Na to the capacitor C1, and the switch K1 is used for switching on or off the charging path of the auxiliary winding Na to the capacitor C1 according to a control signal (denoted as Vk 1).
It can be understood that the charging path of the auxiliary winding Na to the capacitor C1 corresponds to the power supply path of the auxiliary winding Na to the primary control chip 20, and thus, in the embodiment of the invention, the charging path of the auxiliary winding Na to the capacitor C1 is also equivalently corresponding to the power supply path of the auxiliary winding Na to the primary control chip 20.
Alternatively, in some embodiments of the present invention, as shown in fig. 2, the switch K1 may be disposed between the auxiliary winding Na and the power supply terminal of the primary control chip 20. Alternatively, in other embodiments of the present invention, as shown in fig. 3, the switch K1 may be disposed between the auxiliary winding Na and the reference ground.
Illustratively, the switch K1 is any one of a field effect transistor and a bipolar transistor. In some embodiments, when the switch K1 is selected to have a parasitic diode (e.g., the switch K1 is an NMOS transistor or a PMOS transistor), the parasitic diode of the switch K1 should be disposed on the charging path of the auxiliary winding Na to the capacitor C1 in a reverse direction, i.e., the anode of the parasitic diode of the switch K1 should face the primary control chip 20, i.e., the anode of the parasitic diode of the switch K1 should be directly or indirectly connected to the power supply terminal of the primary control chip 20. For example, when the switch K1 is disposed between the auxiliary winding Na and the power supply terminal of the primary control chip 20, as shown in fig. 2, the cathode of the parasitic diode of the switch K1 is connected to the auxiliary winding Na, and the anode is connected to the power supply terminal of the primary control chip 20; when the switch K1 is disposed between the auxiliary winding Na and the reference ground, as shown in fig. 3, the cathode of the parasitic diode of the switch K1 is connected to the reference ground, and the anode is connected to the power supply terminal of the primary control chip 20 through the auxiliary winding Na. Therefore, when the capacitor C1 does not need to be charged and the switch K1 is in the off state, the charging path of the auxiliary winding Na to the capacitor C1 can be prevented from being communicated through the parasitic diode of the switch K1 to continuously charge the capacitor C1, and the accuracy and the reliability of on-off control of the charging path are improved.
For example, since the voltage across the auxiliary winding Na has a negative voltage of half a switching period, in order to avoid discharging the capacitor C1 when the voltage across the auxiliary winding Na is negative, the diode D2 is connected in series to the charging path of the auxiliary winding Na to the capacitor C1, and the cathode of the diode D2 is connected to the power supply terminal of the primary control chip 20. The diode D2 can avoid the reverse power supply of the auxiliary winding Na by the power supply terminal voltage of the primary control chip 20, which is beneficial to improving the accuracy and stability of the power supply voltage Vcc provided to the primary control chip 20.
The detection module 31 is configured to detect the power supply voltage Vcc and compare the power supply voltage Vcc with a preset value (denoted as Vref) to generate a control signal Vk1 according to the comparison result.
In this embodiment, the detection module 31 is specifically configured to output a control signal Vk1 having a first level state to control the switch K1 to be turned on when the power supply voltage Vcc is lower than the preset value Vref, so as to communicate with the charging path of the capacitor C1 by the auxiliary winding Na, and utilize the auxiliary winding voltage V AUX The primary control chip 20 is powered and the capacitor C1 is charged to raise the power supply voltage Vcc; or when the power supply voltage Vcc is higher than the preset value Vref, the control signal Vk1 with the second level state is output to control the switch K1 to be turned off, so that a charging path of the auxiliary winding Na to the capacitor C1 is disconnected, and the primary control chip 20 is powered by only the voltage on the capacitor C1 to reduce power consumption. The first level state is one of a high level state and a low level state, and the second level state is the other of the high level state and the low level state.
It can be understood that the detection module 31 and the switch K1 form a feedback loop of the power supply voltage Vcc, and the power supply voltage can be basically stabilized near the preset value Vref by the feedback adjustment of the power supply voltage Vcc by the switch K1 and the detection module 31 in the embodiment of the invention, that is, the stable power supply to the primary control chip 20 is realized by a simple power supply circuit 30 structure and a simple control method, thereby effectively reducing the hardware cost and being beneficial to realizing the miniaturization of the system. In the whole power supply process of the primary side control chip 20, the charging process of the auxiliary winding Na to the capacitor C1 is not continuously performed, so that the system power consumption can be reduced.
In addition, the power supply circuit 30 disclosed in the embodiment of the present invention does not provide an additional inductor for the auxiliary winding voltage V AUX Boosting is performed, and instead an appropriate auxiliary winding voltage V that can meet the power supply demand to the primary control chip 20 is directly obtained by, for example, adjusting the turns ratio of the auxiliary winding Na to the secondary winding Ns AUX Therefore, the hardware cost and the design area of the system can be further reduced, and the circuit structure is simpler.
Further, the invention also provides a power supply method of the flyback converter, which can be used in the flyback converter described in the foregoing fig. 2 and 3. As shown in fig. 4, the power supply method includes performing the steps of:
in step S1, the supply voltage of the primary side control chip is detected.
In this embodiment, the detection module 31 may be used to sample and detect the power supply voltage Vcc of the primary control chip 20.
In step S2, the supply voltage is compared with a preset value.
Alternatively, in some embodiments of the present invention, the preset value Vref corresponds to a voltage value within a range of power supply voltages required by the primary control chip 20, and at this time, a circuit with a voltage comparing function may be used to compare the magnitude relationship between the power supply voltage Vcc and the preset value Vref, so as to stabilize the power supply voltage Vcc around the preset value Vref. In other embodiments of the present invention, the preset value Vref may also correspond to two voltage values representing the range of the power supply voltage required by the primary control chip 20, and a circuit with a hysteresis comparison function may be used to compare the power supply voltage Vcc with the voltage range, so as to stabilize the power supply voltage Vcc within the voltage range.
In step S3, the unidirectional conductive power supply path of the auxiliary winding in the transformer to the primary control chip is connected or disconnected according to the comparison result.
In this embodiment, the unidirectional conductive power supply path for connecting or disconnecting the auxiliary winding in the transformer to the primary control chip according to the comparison result includes: the charging path of the auxiliary winding Na to the first capacitor, i.e., the capacitor C1, is turned on or off according to the comparison result to equivalently turn on or off the unidirectional conductive power supply path of the auxiliary winding Na to the primary control chip 20. It is understood that a diode, in which the cathode is connected to the power supply terminal of the primary control chip, may be disposed on the power supply path of the auxiliary winding and the primary control chip to achieve unidirectional performance of the power supply path.
Step S3 further comprises: when the power supply voltage Vcc is lower than a preset value Vref, a power supply path of the auxiliary winding Na to the primary side control chip 20 is communicated; or the auxiliary winding Na turns off the power supply path to the primary control chip 20 when the power supply voltage Vcc is higher than the preset value Vref.
It should be noted that, the specific implementation of each step in the power supply method of the flyback converter described above may refer to the foregoing embodiment of the flyback converter, which is not described herein again.
In summary, the embodiment of the invention controls the on-off of the charging path of the auxiliary winding to the first capacitor through the detection and comparison of the power supply voltage and the preset value, and further, the power supply voltage of the primary control chip can be stabilized near the preset value only by presetting the proper output voltage of the auxiliary winding; in the whole process, the charging process of the capacitor is not continuously performed, and an additional inductor is not required to be arranged in the charging process, so that the circuit structure and the control method are simpler, and the circuit power consumption is lower.
Finally, it should be noted that: it is apparent that the above examples are only illustrative of the present invention and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.

Claims (9)

1. A power supply circuit for a flyback converter, the flyback converter comprising: the transformer, main switch tube and primary control chip, power supply circuit is used for the primary control chip provides supply voltage, wherein, power supply circuit includes:
the first capacitor is connected with the power supply end of the primary side control chip and is used for providing power supply voltage for the primary side control chip;
the first switch and the first diode are arranged on a charging path of the auxiliary winding in the transformer to the first capacitor in series, and the first switch is used for connecting or disconnecting the charging path according to a control signal;
the detection module is used for detecting the power supply voltage, comparing the power supply voltage with a preset value and generating the control signal according to a comparison result.
2. The power supply circuit of claim 1, wherein the detection module is configured to control the first switch to be turned on to connect the charging path when the supply voltage is below the preset value or to be turned off to disconnect the charging path when the supply voltage is above the preset value.
3. The power supply circuit of claim 1, wherein the first switch is disposed between the auxiliary winding and a power supply terminal of the primary control chip; or alternatively
The first switch is disposed between the auxiliary winding and a reference ground.
4. A power supply circuit according to claim 3, wherein the first switch is any one of a field effect transistor and a bipolar transistor.
5. The power supply circuit of claim 4, wherein when the first switch has a parasitic diode, the parasitic diode is disposed in a reverse direction on a charging path of the auxiliary winding to the first capacitor.
6. A flyback converter, comprising:
the transformer comprises a primary winding, a secondary winding and an auxiliary winding;
the main switch tube is connected in series between the primary winding and the voltage input end or the reference ground;
the primary side control chip is used for providing control signals for the main switching tube;
the supply circuit of any one of claims 1-5 for providing a supply voltage for the primary side control chip.
7. A method of powering a flyback converter, the flyback converter comprising: the transformer, the main switching tube and the primary side control chip which comprise auxiliary windings are included, wherein the power supply method comprises the following steps:
detecting the power supply voltage of the primary side control chip;
comparing the power supply voltage with a preset value;
and connecting or disconnecting a unidirectional conductive power supply path of the auxiliary winding in the transformer to the primary side control chip according to the comparison result.
8. The power supply method according to claim 7, wherein turning on or off a unidirectional conductive power supply path of an auxiliary winding in the transformer to the primary control chip according to a comparison result comprises: and connecting or disconnecting the charging path of the auxiliary winding to the first capacitor according to the comparison result so as to equivalently connect or disconnect the unidirectional conductive power supply path of the auxiliary winding to the primary control chip.
9. The power supply method according to claim 7 or 8, wherein the power supply path is connected when the power supply voltage is lower than the preset value; or alternatively
And when the power supply voltage is higher than the preset value, the power supply path is disconnected.
CN202211641633.1A 2022-12-20 2022-12-20 Power supply circuit and power supply method of flyback converter and flyback converter Pending CN116365827A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211641633.1A CN116365827A (en) 2022-12-20 2022-12-20 Power supply circuit and power supply method of flyback converter and flyback converter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211641633.1A CN116365827A (en) 2022-12-20 2022-12-20 Power supply circuit and power supply method of flyback converter and flyback converter

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Publication Number Publication Date
CN116365827A true CN116365827A (en) 2023-06-30

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