Switching control circuit with energy recycling function and switching control method

Abstract

The invention discloses a conversion control circuit with an energy recycling function and a conversion control method. The conversion control circuit with the energy recycling function is used for controlling an isolated power converter so as to convert an input power supply to generate an output power supply. The conversion control circuit generates an optical coupling current to an optical diode included in the optical coupler according to the control related signal, and transmits information of the control related signal between the primary side and the secondary side of the power converter in an optical coupling mode so as to realize power conversion. The conversion control circuit comprises a controllable current source circuit used for generating a controllable current according to a control related signal, and at least one part of the controllable current is used for providing an optical coupling current; and the power conversion circuit is used for converting at least one part of the optical coupling current into a power supply so as to supply power to the operation circuit, so that the energy generated by the optical coupling current is recycled.

Description

Technical Field

[0001] The present invention relates to a conversion control circuit with an energy recycling function and a conversion control method with an energy recycling function, and particularly to a conversion control circuit and a conversion control method that can recycle the energy generated by the photocoupling current used to drive a photocoupler through a first power conversion circuit and / or a second power conversion circuit. Background Art

[0002] The known isolated conversion control circuit provides a photocoupling current to transmit information between the primary side and the secondary side through a photocoupler to achieve power conversion. The photocoupling current causes a certain proportion of power consumption in the extremely light load state.

[0003] In view of this, the present invention aims at the above deficiencies of the prior art, and proposes a conversion control circuit and a conversion control method that can recycle the energy generated by the photocoupling current related to the output power supply through a first power conversion circuit and / or a second power conversion circuit, thereby improving the power conversion efficiency of the isolated power converter. Summary of the Invention

[0004] In one aspect, the present invention provides a conversion control circuit with an energy recycling function for controlling an isolated power converter that converts an input power supply to generate an output power supply. The isolated power converter has a primary side coupled to the input power supply and a secondary side coupled to the output power supply. The conversion control circuit generates a photocoupling current for a photodiode included in a photocoupler according to a control-related signal, thereby transmitting information related to the control-related signal SVR between the primary side and the secondary side in a photocoupling manner to achieve the above-mentioned power conversion. The conversion control circuit includes: a controllable current source circuit for generating a controllable current according to the control-related signal, at least a part of the controllable current being used to provide the photocoupling current; and a first power conversion circuit for converting at least a part of the photocoupling current into a supply power supply to supply power to an operation circuit, thereby recycling the energy generated by the photocoupling current.

[0005] In one embodiment, the conversion control circuit with an energy recycling function further includes: a second power conversion circuit for providing a regulated power supply, the regulated power supply and the supply power supply being connected in parallel to supply power to the operation circuit.

[0006] In one embodiment, the operation circuit consumes an operation current to operate; wherein a regulated current of the regulated power supply is related to a difference between at least a part of the photocoupling current and the operation current; or the regulated current is related to a difference between a supply current of the supply power supply and the operation current.

[0007] In one embodiment, the first power conversion circuit is a linear voltage regulator or a switching power converter.

[0008] In one embodiment, the second power conversion circuit is a linear voltage regulator or a switching power converter.

[0009] In one embodiment, the control-related signal is related to an electrical characteristic of the output power supply, and the conversion control circuit adjusts the electrical characteristic to a preset target level according to the control-related signal.

[0010] In one embodiment, the controllable current source circuit includes a transconductance amplifier for converting the difference between the electrical characteristic and the reference signal to generate the controllable current.

[0011] In one embodiment, the electrical characteristic is an output voltage or an output current of the output power supply.

[0012] In one embodiment, the controllable current source circuit is coupled in parallel with the first power converter to the photodiode; or the controllable current source circuit, the first power converter, and the photodiode are serially coupled to each other.

[0013] In one embodiment, the regulating current is bidirectional regulation.

[0014] In one embodiment, the isolated power converter is a flyback power converter, where the flyback power converter includes: a power transformer coupled between the input power supply and the output power supply; a half-bridge circuit composed of a primary-side upper-bridge switch and a primary-side lower-bridge switch for switching a resonant circuit composed of a primary-side winding of the power transformer and a resonant capacitor; and a synchronous rectifying (SR) switch serially coupled with a secondary-side winding of the power transformer between the output power supply and a secondary-side ground node; where the primary-side upper-bridge switch and the primary-side lower-bridge switch are controlled by a primary-side control circuit, where the primary-side control circuit is coupled to a phototransistor included in the optocoupler for generating a switching signal, where the switching signal is used to control the primary-side upper-bridge switch and the primary-side lower-bridge switch to switch the primary-side winding of the power transformer; where the synchronous rectifying switch is controlled by a secondary-side control circuit, where the secondary-side control circuit is used to generate the photocoupling current to drive the photodiode and is used to generate a synchronous rectifying control signal to control the conduction and turn-off of the synchronous rectifying switch to switch the secondary-side winding of the power transformer to generate the output voltage; where the conversion control circuit includes the secondary-side control circuit.

[0015] In one embodiment, the second power conversion circuit is used to convert the output voltage Vout or the voltage across an auxiliary winding included in the power transformer to generate the regulating current.

[0016] In another aspect, the present invention provides a conversion control method with an energy recycling function for controlling an isolated power converter that converts an input power supply to generate an output power supply. The isolated power converter has a primary side coupled to the input power supply and a secondary side coupled to the output power supply. The conversion control method generates an opto-coupling current for an opto-diode included in an opto-coupler according to a control-related signal, thereby transmitting information related to the control-related signal SVR between the primary side and the secondary side in an opto-coupling manner to achieve the power conversion. The conversion control method includes: generating a controllable current according to the control-related signal, where at least a part of the controllable current is used to provide the opto-coupling current; and converting at least a part of the opto-coupling current into a supply power supply to supply power to an operating circuit, thereby recycling the energy generated by the opto-coupling current.

[0017] In one embodiment, the conversion control method with an energy recycling function further includes: providing a regulated power supply, where the regulated power supply and the supply power supply are connected in parallel to supply power to the operating circuit.

[0018] In one embodiment, the conversion control method with an energy recycling function further includes: converting the difference between the electrical characteristics and the reference signal to generate the controllable current.

[0019] In one embodiment, the regulating current is bidirectional regulation.

[0020] In one embodiment, the conversion control method with an energy recycling function further includes: converting the output voltage or the voltage across an auxiliary winding to generate the regulating current.

[0021] The following will be described in detail through specific embodiments to more easily understand the purpose, technical content, features, and achieved effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1A is a circuit block diagram showing a conversion control circuit with an energy recycling function according to an embodiment of the present invention.

[0023] Figure 1B is a circuit block diagram showing a conversion control circuit with an energy recycling function according to another embodiment of the present invention.

[0024] Figure 2It is a circuit block diagram showing a conversion control circuit with an energy recycling function according to an embodiment of the present invention, where the control-related signal is related to the difference between the electrical characteristics of the output power supply and the reference signal.

[0025] Figure 3A It is a circuit block diagram showing a conversion control circuit with an energy recycling function according to an embodiment of the present invention, where the controllable current source circuit, the first power converter, and the photodiode are serially coupled to each other.

[0026] Figure 3B It is a circuit block diagram showing a conversion control circuit with an energy recycling function according to another embodiment of the present invention, where the controllable current source circuit and the first power converter are coupled in parallel to the photodiode.

[0027] Figure 4A It is a circuit block diagram showing a conversion control circuit with an energy recycling function according to an embodiment of the present invention, where the conversion control circuit further includes a second power conversion circuit coupled in parallel with the first power converter, and the controllable current source circuit, the first power converter, and the photodiode are serially coupled to each other.

[0028] Figure 4B It is a circuit block diagram showing a conversion control circuit with an energy recycling function according to another embodiment of the present invention, where the conversion control circuit further includes a second power conversion circuit coupled in parallel with the first power converter, and the controllable current source circuit and the first power converter are coupled in parallel to the photodiode.

[0029] Figure 5 It is a block diagram showing that the first power conversion circuit in the conversion control circuit with an energy recycling function is a linear voltage regulator according to an embodiment of the present invention.

[0030] Figure 6 It is a block diagram showing that the second power conversion circuit in the conversion control circuit with an energy recycling function is a linear voltage regulator according to an embodiment of the present invention.

[0031] Figures 7A - 7C It is a schematic diagram showing that the first power conversion circuit in the conversion control circuit with an energy recycling function is a switching power converter in different forms according to an embodiment of the present invention.

[0032] Figures 8A - 8C It is a schematic diagram showing that the second power conversion circuit in the conversion control circuit with an energy recycling function is a switching power converter in different forms according to an embodiment of the present invention.

[0033] Figure 9AIt is a circuit diagram showing that the controllable current source circuit in the conversion control circuit with the function of recycling energy is a transconductance amplifier according to an embodiment of the present invention.

[0034] Figure 9B It is a circuit diagram showing that the controllable current source circuit in the conversion control circuit with the function of recycling energy is a transconductance amplifier according to another embodiment of the present invention.

[0035] Figure 10 It is a circuit block diagram showing that the isolated power converter in the conversion control circuit with the function of recycling energy is a flyback power converter according to another embodiment of the present invention.

[0036] Symbol Explanation in the Figure

[0037] 100, 100b, 100b’: Conversion control circuit

[0038] 101: Controllable current source circuit

[0039] 1011: First transconductance amplifier

[0040] 1012: Second transconductance amplifier

[0041] 102a: First power conversion circuit

[0042] 102a1: Linear voltage regulation

[0043] 102b: Second power conversion circuit

[0044] 102b1: Linear voltage regulator

[0045] 103: Operation circuit

[0046] 200: Isolated power converter

[0047] 230: Power transformer

[0048] 300: Optocoupler

[0049] 301: Phototransistor

[0050] 302: Photodiode

[0051] COMP: Compensation signal

[0052] GND: Secondary side ground node

[0053] I1: Supply current

[0054] I2: Regulating current

[0055] I1’: Current

[0056] IFB: Feedback current signal

[0057] Igm: Controllable current

[0058] Igm1: First controllable current

[0059] Igm2: Second controllable current

[0060] Iin: Input current

[0061] IOPTO: Opto - coupled current

[0062] Iout: Output current

[0063] OA1, OA2, OA3: Amplifiers

[0064] RCS: Sensing resistor

[0065] S1: Primary - side switch

[0066] S2: Synchronous rectification switch

[0067] SG1: Switching signal

[0068] SG2: Synchronous rectification control signal

[0069] SVR: Control - related signal

[0070] Tt1: First transduction transistor

[0071] Tt2: Second transduction transistor

[0072] Wp: Primary - side winding

[0073] Ws: Secondary - side winding

[0074] Wa: Auxiliary winding

[0075] V1: Supply voltage

[0076] V2: Regulated voltage

[0077] Vaux: Auxiliary - winding voltage across

[0078] VCS: Sensing voltage

[0079] VFB: Feedback voltage signal

[0080] Vin: Input voltage

[0081] Vout: Output voltage

[0082] Vref, VREF_CV, VREF_CC: Reference signal Detailed implementation manners

[0083] The drawings in the present invention are all schematic, mainly intended to show the coupling relationship between each circuit and the relationship between each signal waveform. As for the circuit, signal waveform and frequency, they are not drawn according to scale.

[0084] Figure 1A FIG. is a circuit block diagram showing a conversion control circuit with an energy recycling function according to an embodiment of the present invention. Figure 1B FIG. is a circuit block diagram showing a conversion control circuit with an energy recycling function according to another embodiment of the present invention. The conversion control circuit 100 with an energy recycling function is used to control an isolated power converter 200, which is used to convert an input power supply to generate an output power supply. The input power supply includes an input voltage Vin and an input current Iin, and the output power supply includes an output voltage Vout and an output current Iout. The isolated power converter 200 has a primary side coupled to the input power supply and a secondary side coupled to the output power supply. In one embodiment, the isolated power converter 200 is configured, for example, as a half-bridge resonant flyback converter (as Figure 1A shown).

[0085] The conversion control circuit 100 generates an opto-coupler current IOPTO for a photodiode 302 included in an opto-coupler 300 according to a control-related signal SVR, thereby transmitting information related to the control-related signal SVR between the primary side and the secondary side in an opto-coupled manner to achieve the above-mentioned power conversion. In one embodiment, as Figure 1A shown, the conversion control circuit 100 can be located on the secondary side, and the information related to the control-related signal SVR is transmitted from the secondary side to the primary side. In another embodiment, as Figure 1B shown, the conversion control circuit 100 can be located on the primary side, and the information related to the control-related signal SVR is transmitted from the primary side to the secondary side.

[0086] Please continue to refer to Figure 1A and Figure 1B , the conversion control circuit 100 includes: a controllable current source circuit 101, which is used to generate a controllable current Igm according to the control-related signal SVR, and at least a part of the controllable current Igm is used to provide the opto-coupler current IOPTO; and a first power conversion circuit 102a, which converts at least a part of the current I1' of the opto-coupler current IOPTO into a supply power supply (corresponding to a supply voltage V1 and a supply current I1) to supply power to an operation circuit 103, thereby recycling the energy generated by the opto-coupler current IOPTO related to the output power supply. Specific detailed embodiments will be described in detail later. It should be noted that the following embodiments will mainly be described by taking the embodiment corresponding to Figure 1A as an example, and Figure 1BThe corresponding detailed embodiments can be analogized.

[0087] Figure 2 FIG. 2 is a circuit block diagram showing a conversion control circuit having an energy recycling function according to an embodiment of the present invention, wherein a control-related signal SVR is related to the electrical characteristics of an output power supply, such as an output voltage Vout or an output current Iout.

[0088] Figure 3A FIG. 3 is a circuit block diagram showing a conversion control circuit having an energy recycling function according to an embodiment of the present invention, and this embodiment corresponds to Figure 2 a more specific embodiment of FIG. 2. In this embodiment, the control-related signal SVR is related to the difference between the electrical characteristics of the output power supply and a reference signal Vref. In one embodiment, the conversion control circuit 100 adjusts the electrical characteristics to a preset target level according to the control-related signal SVR. Specifically, for example, the control-related signal SVR related to the difference between the electrical characteristics of the output power supply and the reference signal Vref controls the optocoupler 300 through an optocoupler current IOPTO, and further controls the primary-side switch of the isolated power converter 200, thereby adjusting the output voltage Vout or the output current Iout to a preset target level.

[0089] Continuing to refer to Figure 3A FIG. 2, in one embodiment, the controllable current source circuit 101, the first power converter 102a, and the photodiode 302 are serially coupled to each other. In other words, in one embodiment, the controllable current Igm, the optocoupler current IOPTO, and the current I1' are substantially equal.

[0090] Figure 3B FIG. 4 is a circuit block diagram showing a conversion control circuit having an energy recycling function according to another embodiment of the present invention, and this embodiment is similar to Figure 3A FIG. 2, except that in the conversion control circuit 100', the controllable current source circuit 100 and the first power converter 102a are parallely coupled to the photodiode 302. In other words, in this embodiment, the optocoupler current IOPTO is equal to the sum of the controllable current Igm and the current I1'.

[0091] Figure 4A FIG. 5 is a circuit block diagram showing a conversion control circuit having an energy recycling function according to an embodiment of the present invention, Figure 4B FIG. 6 is a circuit block diagram showing a conversion control circuit having an energy recycling function according to another embodiment of the present invention. Figure 4A and Figure 4B the embodiments of FIG. 6 are respectively similar to Figure 3A and Figure 3BEmbodiments, differing in that the conversion control circuits 100b and 100b' with the function of recycling energy respectively further include: a second power conversion circuit 102b for providing a regulated power supply, wherein the regulated power supply and the supply power supply are connected in parallel with each other to supply power to the operation circuit 103. In an embodiment, the operation circuit 103 consumes an operation current I3 for operation, such as Figure 4A and Figure 4B shown. In this embodiment, the regulated current I2 is related to a difference between the supply current I1 and the operation current I3. From one perspective, a regulated current I2 of the regulated power supply is related to a difference between at least a part of the photocoupling current IOPTO, i.e., the current I1', and the operation current I3. In an embodiment, the regulated current I2 is bidirectional regulation, that is, the regulated current I2 shown in the figure can flow out or flow into the second power conversion circuit 102b.

[0092] Continue to refer to Figure 4A and Figure 4B , in an embodiment, the second power conversion circuit 102b can convert the output voltage Vout or a voltage across an auxiliary winding Vaux (auxiliary voltage) included in the power transformer 230 to generate the regulated current I2.

[0093] Figure 5 is a block diagram showing a first power conversion circuit 102a in a conversion control circuit with the function of recycling energy according to an embodiment of the present invention. As Figure 5 shown, in an embodiment, the first power conversion circuit 102a can be configured as a linear voltage regulator 102a1 for converting the current I1' in a linear control manner to generate a supply power supply (V1, I1).

[0094] Figure 6 is a block diagram showing a second power conversion circuit 102b in a conversion control circuit with the function of recycling energy according to an embodiment of the present invention. As Figure 6 shown, in an embodiment, the second power conversion circuit 102b can be configured as a linear voltage regulator 102a1 for converting the output voltage Vout or the auxiliary voltage Vaux in a linear control manner to generate a regulated power supply (V2, I2).

[0095] In an embodiment, the first power conversion circuit 102a can also be configured as a switching power converter. Figures 7A - 7C is a schematic diagram showing a first power conversion circuit 102a in a conversion control circuit with the function of recycling energy according to an embodiment of the present invention. As Figures 7A - 7CAs shown, the first power conversion circuit 102a can be configured as a buck, boost, or buck-boost switching power converter, and converts the current I1' in a switching control manner to generate a supply power (V1, I1).

[0096] Figures 8A - 8C FIG. is a schematic diagram showing a second power conversion circuit 102b in a conversion control circuit having an energy recycling function according to an embodiment of the present invention. As Figures 8A - 8C shown, the second power conversion circuit 102b is a buck, boost, or buck-boost switching power converter, and converts the output voltage Vout or the auxiliary voltage Vaux in a switching control manner to generate a regulated power (V2, I2).

[0097] Figure 9A FIG. is a circuit diagram showing a controllable current source circuit including a transconductance amplifier in a conversion control circuit having an energy recycling function according to an embodiment of the present invention. This embodiment corresponds to Figure 4A the embodiment of, that is, the controllable current source circuit 101, the first power converter 102a, and the photodiode 302 are serially coupled to each other. In this embodiment, the controllable current source circuit 101 includes a transconductance amplifier 1011 and / or a transconductance amplifier 1012, and is used to generate the controllable current Igm according to the difference between the feedback voltage signal VFB related to the output voltage Vout and the voltage reference signal VREF_CV, and / or according to the difference between the feedback current signal IFB related to the output current Iout and the current reference signal VREF_CC. The feedback voltage signal VFB is, for example, a voltage division of the output voltage Vout, and the feedback current signal IFB is, for example, a sensing signal proportional to the output current Iout.

[0098] Continuing to refer to Figure 9A , specifically, this embodiment includes two feedback loops. One is a constant voltage control loop, which generates the controllable current Igm according to the difference between the feedback voltage signal VFB and the voltage reference signal VREF_CV, and then controls the isolated power converter to perform power conversion to adjust the output voltage Vout to a preset level. The other of the two feedback loops is a constant current control loop, which generates the controllable current Igm according to the difference between the feedback current signal IFB and the current reference signal VREF_CC, and adjusts the output current Iout to a preset level.

[0099] Figure 9B FIG. is a circuit diagram showing a controllable current source circuit including a transconductance amplifier in a conversion control circuit having an energy recycling function according to another embodiment of the present invention. Figure 9B Similar to Figure 9A , the difference is that Figure 9B corresponding to Figure 4BAn embodiment, that is, the controllable current source circuit 101 and the first power converter 102a are connected in parallel to the photodiode 302.

[0100] Figure 10 FIG. 4 is a schematic circuit diagram showing that the isolated power converter 200 in the conversion control circuit with an energy recycling function is a flyback power converter according to another embodiment of the present invention. The isolated power converter 200 is a flyback power converter, which includes: a power transformer 230 coupled between the input power supply and the output power supply; a half-bridge circuit composed of a primary-side upper-bridge switch S1 and a primary-side lower-bridge switch S2 for switching a resonant circuit composed of a primary-side winding Wp of the power transformer 230 and a resonant capacitor Cr; a synchronous rectifying (SR) switch SSR connected in series with a secondary-side winding Ws of the power transformer 230 between the output power supply and a secondary-side ground node GND. The conversion control circuit 100 includes: a primary-side control circuit 210 coupled to a photosensitive transistor 301 included in the optocoupler 300 for generating a switching signal SG1, where the switching signals SG1 and SG2 are used to control the primary-side upper-bridge switch S1 and the primary-side lower-bridge switch S2 to switch the primary-side winding Wp of the power transformer 230; and a secondary-side control circuit 220 coupled to the photodiode 302 for generating a synchronous rectifying control signal SGR to control the conduction and turn-off of the synchronous rectifying switch S2 to switch the secondary-side winding Ws of the power transformer 230 to generate the output voltage Vout. In this embodiment, the secondary-side controller is used to generate an optocoupler current IOPTO to drive the photodiode 302.

[0101] The present invention has been described above with reference to the preferred embodiments. However, the above description is only for the convenience of those skilled in the art to understand the content of the present invention, and is not used to limit the scope of the rights of the present invention. Each of the described embodiments is not limited to being applied alone, and can also be applied in combination. For example, two or more embodiments can be combined, and some components in one embodiment can also be used to replace the corresponding components in another embodiment. In addition, under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations. For example, the phrase "processing or operating or generating a certain output result according to a certain signal" as used in the present invention is not limited to the signal itself, but also includes, when necessary, performing voltage-current conversion, current-voltage conversion, and / or ratio conversion on the signal, and then processing or operating on the converted signal to generate a certain output result. From this, it can be seen that under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations, and there are many combination methods, which are not listed one by one here. Therefore, the scope of the present invention should cover the above and all other equivalent changes.

Claims

1. A conversion control circuit with the function of recycling energy is used to control an isolated power converter, which is used to convert an input power supply to generate an output power supply. The isolated power converter has a primary side coupled to the input power supply and a secondary side coupled to the output power supply. The conversion control circuit generates an opto-coupler current for a photo-diode included in an opto-coupler according to a control-related signal, thereby transmitting information related to the control-related signal between the primary side and the secondary side in an opto-coupled manner to achieve the above-mentioned power conversion. The conversion control circuit includes: A controllable current source circuit is used to generate a controllable current according to the control-related signal, and at least a part of the controllable current is used to provide the opto-coupler current; and A first power conversion circuit converts at least a part of the opto-coupler current into a supply power supply to supply power to an operation circuit, thereby recycling the energy generated by the opto-coupler current.

2. The conversion control circuit with the function of recycling energy as described in claim 1, wherein, It further includes: A second power conversion circuit is used to provide a regulated power supply, and the regulated power supply and the supply power supply are connected in parallel to supply power to the operation circuit.

3. The conversion control circuit with the function of recycling energy as described in claim 2, wherein, The operation circuit consumes an operation current to operate; Wherein a regulated current of the regulated power supply is related to a difference between at least a part of the opto-coupler current and the operation current; Or The regulated current is related to a difference between a supply current of the supply power supply and the operation current.

4. The conversion control circuit with the function of recycling energy as described in claim 1, wherein, The first power conversion circuit is a linear voltage regulator or a switching power converter.

5. The conversion control circuit with the function of recycling energy as described in claim 2, wherein, The second power conversion circuit is a linear voltage regulator or a switching power converter.

6. The conversion control circuit with the function of recycling energy as claimed in claim 1, wherein, The control-related signal is related to an electrical characteristic of the output power supply, and the conversion control circuit adjusts the electrical characteristic to a preset target level according to the control-related signal.

7. The conversion control circuit having the function of recycling energy as claimed in claim 6, wherein, The controllable current source circuit includes a transconductance amplifier, which is used to convert the difference between the electrical characteristic and the reference signal to generate the controllable current.

8. The conversion control circuit with the function of recycling energy as described in claim 7, wherein, The electrical characteristic is an output voltage or an output current of the output power supply.

9. The conversion control circuit with the function of recycling energy as described in claim 1, wherein, The controllable current source circuit is connected in parallel with the first power converter to the photo-diode; or Wherein the controllable current source circuit, the first power converter and the photo-diode are connected in series with each other.

10. The conversion control circuit with the function of recycling energy as claimed in claim 2, wherein, The regulated current is two-way regulated.

11. The conversion control circuit with the function of recycling energy as claimed in claim 1, wherein, The isolated power converter is a flyback power converter, and the flyback power converter includes: A power transformer is coupled between the input power supply and the output power supply; A half-bridge circuit composed of a primary-side upper-bridge switch and a primary-side lower-bridge switch is used to switch a resonant circuit composed of a primary-side winding of the power transformer and a resonant capacitor; and A synchronous rectification switch is connected in series with a secondary-side winding of the power transformer between the output power supply and a secondary-side ground node; The primary side upper bridge switch and the primary side lower bridge switch are controlled by a primary side control circuit, and the primary side control circuit is coupled to a photosensitive transistor included in the optocoupler to generate a switching signal for controlling the primary side upper bridge switch and the primary side lower bridge switch to switch the primary side winding of the power transformer; The synchronous rectification switch is controlled by a secondary side control circuit, and the secondary side control circuit is used to generate the photocoupling current to drive the photodiode and generate a synchronous rectification control signal to control the conduction and turn-off of the synchronous rectification switch, thereby switching the secondary side winding of the power transformer to generate the output voltage; The conversion control circuit includes the secondary side control circuit.

12. The conversion control circuit with the function of recycling energy as described in claim 11, wherein, The second power conversion circuit is used to convert the output voltage or the voltage across an auxiliary winding included in the power transformer to generate the regulation current.

13. A conversion control method with an energy recycling function for controlling an isolated power converter that converts an input power supply to generate an output power supply. The isolated power converter has a primary side coupled to the input power supply and a secondary side coupled to the output power supply. The conversion control method generates a photocoupling current for a photodiode included in an optocoupler according to a control-related signal, thereby transmitting information related to the control-related signal between the primary side and the secondary side in a photocoupling manner to achieve the power conversion. The conversion control method includes: Generating a controllable current according to the control-related signal, and at least a part of the controllable current is used to provide the photocoupling current; and Converting at least a part of the photocoupling current into a supply power supply to supply power to an operating circuit, thereby recycling the energy generated by the photocoupling current.

14. The conversion control method with the function of recycling energy as claimed in claim 13, wherein, It further includes: Providing a regulated power supply, and the regulated power supply and the supply power supply are connected in parallel to supply power to the operating circuit.

15. The conversion control method with the function of recycling energy as described in claim 14, wherein, The operating circuit consumes an operating current to operate; Wherein a regulation current of the regulated power supply is related to a difference between at least a part of the photocoupling current and the operating current; Or The regulation current is related to a difference between a supply current of the supply power supply and the operating current.

16. The conversion control method with the function of recycling energy as described in claim 13, wherein, The control-related signal is related to an electrical characteristic of the output power supply, and the electrical characteristic is adjusted to a preset target level according to the control-related signal.

17. The conversion control method with the function of recycling energy as claimed in claim 13, wherein, It further includes: Converting the difference between the electrical characteristic and the reference signal to generate the controllable current.

18. The conversion control method with the function of recycling energy as claimed in claim 17, wherein, The electrical characteristic is an output voltage or an output current of the output power supply.

19. The conversion control method with the function of recycling energy as claimed in claim 15, wherein, The regulation current is bidirectionally regulated.

20. The conversion control method with the function of recycling energy as described in claim 19, wherein, It further includes: Converting the output voltage or the voltage across an auxiliary winding to generate the regulation current.

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