Isolation power supply circuit, isolation power supply, control method, chip and electronic equipment

Abstract

The invention provides an isolation power supply circuit, a control method, an isolation power supply, a chip and electronic equipment. A first signal is transmitted to the secondary control circuit through the load detection circuit. And when the first signal indicates that the load is not connected to the isolation power supply circuit, the secondary control circuit pulls down the voltage of the output end of the optical coupling element, turns off the optical coupling element after a preset time length, and pulls down the output voltage of the isolation power supply circuit within the preset time length. When the voltage of the output end of the optical coupling element rises, the primary control circuit transmits a second signal to the primary power loop. Upon receiving the second signal, the primary power loop transmits a third signal to the primary control circuit. And the primary control circuit enters a low-power-consumption mode when detecting that the output voltage of the isolation power supply circuit is lowered according to the third signal. The secondary side communicates with the primary side through the optical coupling element. Therefore, the cost of the isolation power supply circuit can be reduced, and the cost of the power adapter can be reduced.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to an isolated power supply circuit, an isolated power supply, a control method, a chip and an electronic device. Background Art

[0002] Usually, electronic products are charged by connecting to the power grid through a power adapter. Most of the time, the power adapter is not connected to the electronic product, that is, not connected to the load. When the power adapter is not connected to the load, the isolated power circuit in the power adapter still needs to adjust the output voltage of the power adapter so that the connected load can be charged at any time.

[0003] Since the units related to the output voltage regulation in the isolated power supply circuit are always in a working state, the energy consumption of the power adapter is serious. Therefore, the isolated power supply circuit additionally introduces a load detection signal transmission unit. In this way, when the power adapter is in a state where the load is not connected, the indication signal used to indicate that the power adapter is not connected to the load is transmitted from the secondary side of the isolated power supply circuit to the primary side of the isolated power supply circuit through the load detection signal transmission unit. Furthermore, after receiving the indication signal, the primary control unit on the primary side of the isolated power supply circuit enters a low power consumption mode, causing the isolated power supply circuit to enter a low power consumption mode. Thus, the power consumption of the isolated power supply circuit can be reduced, and the energy consumption of the power adapter can be reduced. Among them, in the low power consumption mode, most of the circuits in the isolated power supply circuit are turned off.

[0004] However, the introduction of the load detection signal transmission unit increases the cost of the isolated power supply circuit, thereby increasing the cost of the power adapter. Summary of the invention

[0005] The present application provides an isolated power supply circuit, a control method, an isolated power supply, a chip and an electronic device, which can reduce the cost of the isolated power supply circuit, thereby reducing the cost of the power adapter.

[0006] In a first aspect, the present application provides an isolated power supply circuit, which includes: a primary power loop, a primary control circuit, a power transformer, a secondary control circuit, a load detection circuit, and an optocoupler element.

[0007] The first end of the primary power circuit is electrically connected to the first end of the power transformer, the second end of the primary power circuit is electrically connected to the first end of the primary control circuit, the second end of the primary control circuit is electrically connected to the output end of the optocoupler element, the third end of the primary control circuit is electrically connected to the third end of the primary power circuit, the first end of the secondary control circuit is electrically connected to the second end of the power transformer, the second end of the secondary control circuit is electrically connected to the first end of the load detection circuit and the input end of the optocoupler element respectively, the second end of the secondary control circuit is also used as the output end of the isolated power supply circuit, the third end of the secondary control circuit is electrically connected to the second end of the load detection circuit, and the fourth end of the secondary control circuit is electrically connected to the control end of the optocoupler element.

[0008] The load detection circuit is used to transmit a first signal to the secondary control circuit, where the first signal is used to indicate whether the isolated power supply circuit is connected to a load.

[0009] The secondary control circuit is used to lower the voltage at the output end of the optocoupler element when the first signal indicates that the isolated power supply circuit is not connected to a load, and to turn off the optocoupler element after a preset time period so that the voltage at the output end of the optocoupler element increases, and to lower the output voltage of the isolated power supply circuit within the preset time period, wherein after the optocoupler element is turned off, the secondary control circuit enters a low power consumption mode.

[0010] The primary control circuit is used to transmit a second signal to the primary power circuit when the voltage at the output end of the optocoupler element increases, and the second signal is used to instruct the primary power circuit to detect changes in the output voltage of the isolated power supply circuit.

[0011] The primary power circuit is used to detect whether the output voltage of the isolation power supply circuit is pulled down through the power transformer after receiving the second signal, obtain a third signal, and transmit the third signal to the primary control circuit.

[0012] The primary control circuit is further configured to enter the low power consumption mode when it is detected, based on the third signal, that the output voltage of the isolated power supply circuit is pulled low, so that the isolated power supply circuit enters the low power consumption mode.

[0013] Through the isolated power supply circuit provided in the first aspect, the load detection circuit can transmit a first signal to the secondary control circuit to indicate whether the isolated power supply circuit is connected to the load, so that the secondary control circuit can obtain the first signal. When the first signal indicates that the isolated power supply circuit is not connected to the load, the secondary control circuit can pull down the voltage at the output end of the optocoupler element, and after a preset time, turn off the optocoupler element, so that the voltage at the output end of the optocoupler element increases, and after the optocoupler element is turned off, the secondary control circuit can enter a low power consumption mode. At the same time, within the preset time, the secondary control circuit can pull down the output voltage of the isolated power supply circuit. In this way, when the voltage at the output end of the optocoupler element increases, the primary control circuit can transmit a second signal to the primary power circuit to indicate the change of the output voltage of the isolated power supply circuit detected by the primary power circuit, so that the primary power circuit can obtain the second signal. In this way, after receiving the second signal, the primary power circuit can detect whether the output voltage of the isolated power supply circuit is pulled down through the power transformer to obtain a third signal. In addition, the primary power circuit can transmit a third signal to the primary control circuit, so that the primary control circuit can obtain the third signal. Furthermore, the primary control circuit can enter a low power mode when it detects that the output voltage of the isolated power supply circuit is pulled down according to the third signal, so that the isolated power supply circuit enters a low power mode. Since the secondary side of the isolated power supply circuit communicates with the primary side of the isolated power supply circuit through an optical coupling element, it is possible to avoid additionally introducing a load detection signal transmission unit in the related art. Thus, the cost of the isolated power supply circuit and the cost of the power adapter can be reduced.

[0014] In a possible design, the secondary control circuit is further used to exit the low power consumption mode and lower the voltage at the output end of the optocoupler element when the first signal indicates that the isolated power supply circuit is connected to a load.

[0015] The primary control circuit is further configured to exit the low power consumption mode when it is detected that the voltage at the output end of the optocoupler element is pulled low.

[0016] In one possible design, the optical coupling element includes: an optical coupler.

[0017] The first end of the optocoupler is electrically connected to the second end of the secondary control circuit, the second end of the optocoupler is electrically connected to the second end of the primary control circuit, the third end of the optocoupler is electrically connected to the ground end of the secondary side of the isolated power supply circuit, the fourth end of the secondary control circuit is electrically connected between the third end of the optocoupler and the ground end of the secondary side of the isolated power supply circuit, and the fourth end of the optocoupler is electrically connected to the ground end of the primary side of the isolated power supply circuit.

[0018] In one possible design, the primary power circuit includes: a third signal output module, a primary switch tube, a first resistor and a first capacitor.

[0019] The first end of the first capacitor is electrically connected to the first end of the auxiliary winding in the power transformer, the fourth end of the primary control circuit is electrically connected between the first end of the first capacitor and the first end of the auxiliary winding in the power transformer, the input end of the third signal output module is electrically connected between the first end of the first capacitor and the first end of the auxiliary winding in the power transformer, the output end of the third signal output module is electrically connected to the first end of the primary control circuit, the first end of the primary switch tube is electrically connected to the primary winding in the power transformer, the control end of the primary switch tube is electrically connected to the third end of the primary control circuit, the second end of the primary switch tube is electrically connected to the first end of the first resistor, and the second end of the first resistor, the second end of the first capacitor, the second end of the auxiliary winding and the ground end of the third signal output module are all electrically connected to the ground end of the primary side of the isolation power supply circuit.

[0020] The third signal output module is used to generate the third signal by coupling the output voltage of the isolation power supply circuit through the power transformer.

[0021] In a possible design, the third signal output module includes: a second resistor and a third resistor.

[0022] The first end of the second resistor is electrically connected between the first end of the first capacitor and the first end of the auxiliary winding in the power transformer, the second end of the second resistor is electrically connected to the first end of the third resistor, the first end of the primary control circuit is electrically connected between the second end of the second resistor and the first end of the third resistor, and the second end of the third resistor is electrically connected to the ground terminal of the primary side of the isolated power supply circuit.

[0023] In one possible design, the primary control circuit is also used to control the primary switch tube to turn on when the voltage at the fourth terminal of the primary control circuit is lower than the first threshold voltage when the isolated power supply circuit enters the low power consumption mode, so that the voltage at the fourth terminal of the primary control circuit increases until the voltage at the fourth terminal of the primary control circuit increases to the second threshold voltage, and control the primary switch tube to turn off so that the output voltage of the isolated power supply circuit is within a preset voltage range.

[0024] In a possible design, the preset voltage range is related to the first threshold voltage, the second threshold voltage, and a turns ratio between the secondary winding of the power transformer and the auxiliary winding of the power transformer.

[0025] In a possible design, the time duration for the voltage at the fourth terminal of the primary control circuit to rise from the first threshold voltage to the second threshold voltage is related to the capacitance of the first capacitor.

[0026] In a second aspect, the present application provides an isolated power supply, including: the isolated power supply circuit in the above-mentioned first aspect and each possible design of the above-mentioned first aspect.

[0027] The beneficial effects of the isolated power supply provided in the above-mentioned second aspect and each possible design of the above-mentioned second aspect can be referred to the beneficial effects brought about by the above-mentioned first aspect and each possible implementation method of the first aspect, and will not be repeated here.

[0028] In a third aspect, the present application provides a control method, which is applied to the isolated power supply circuit in the first aspect and each possible design of the first aspect or the isolated power supply in the second aspect, and the method includes:

[0029] The load detection circuit transmits a first signal to the secondary control circuit, where the first signal is used to indicate whether the isolated power supply circuit is connected to a load.

[0030] When the first signal indicates that the isolated power supply circuit is not connected to a load, the secondary control circuit pulls down the voltage at the output end of the optocoupler element, and after a preset time, turns off the optocoupler element, so that the voltage at the output end of the optocoupler element increases, and within the preset time, pulls down the output voltage of the isolated power supply circuit, wherein after the optocoupler element is turned off, the secondary control circuit enters a low power consumption mode;

[0031] When the voltage at the output end of the optocoupler element increases, the primary control circuit transmits a second signal to the primary power circuit, where the second signal is used to instruct the primary power circuit to detect changes in the output voltage of the isolated power supply circuit.

[0032] After receiving the second signal, the primary power circuit detects whether the output voltage of the isolation power supply circuit is pulled down through the power transformer, obtains a third signal, and transmits the third signal to the primary control circuit.

[0033] When the primary control circuit detects, based on the third signal, that the output voltage of the isolated power supply circuit is pulled low, the primary control circuit enters the low power consumption mode, so that the isolated power supply circuit enters the low power consumption mode.

[0034] In one possible design, the method further includes:

[0035] When the first signal indicates that the isolated power supply circuit is connected to a load, the secondary control circuit exits the low power consumption mode and pulls down the voltage at the output end of the optocoupler element.

[0036] When the primary control circuit detects that the voltage at the output end of the optocoupler element is pulled low, the primary control circuit exits the low power consumption mode.

[0037] In a fourth aspect, the present application provides a chip, comprising: the isolated power supply circuit in the above-mentioned first aspect and each possible design of the above-mentioned first aspect or the isolated power supply in the above-mentioned second aspect.

[0038] In a fifth aspect, the present application provides an electronic device, comprising: the chip in the fourth aspect above.

[0039] The above description is only an overview of the technical solution of the embodiment of the present application. In order to more clearly understand the technical means of the embodiment of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, a brief introduction will be given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 It is a structural schematic diagram of an isolated power supply circuit in the related art;

[0042] Figure 2 A schematic diagram of the structure of an isolated power supply circuit provided in one embodiment of the present application;

[0043] Figure 3 A flow chart of a control method provided in one embodiment of the present application;

[0044] Figure 4 A schematic diagram of the structure of an isolated power supply circuit provided in one embodiment of the present application;

[0045] Figure 5 A schematic diagram of a flow chart of adjusting output voltage of an isolated power supply circuit provided in one embodiment of the present application;

[0046] Figure 6 A schematic diagram of a working waveform of an isolated power supply circuit provided in one embodiment of the present application;

[0047] Figure 7A schematic diagram of operating waveforms of an isolated power supply circuit provided in one embodiment of the present application. DETAILED DESCRIPTION

[0048] In this application, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c alone can represent: a, b, c, a and b, a and c, or a, b, and c, where a, b, and c can be single or multiple. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0049] The directions or positional relationships indicated by terms such as "center", "longitudinal", "lateral", "up", "down", "left", "right", "front", and "back" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0050] The terms "connected" and "connected" should be understood in a broad sense. For example, the "connected" or "connected" of a circuit structure can refer to not only physical connection, but also electrical connection or signal connection. For example, it can be directly connected, that is, physically connected, or indirectly connected through at least one intermediate element, as long as the circuit is connected, or it can be the internal connection of two elements; signal connection can refer to signal connection through a circuit or through a media medium, such as radio waves. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0051] As more and more electronic products are used, the demand for charging electronic products is also increasing. Usually, electronic products are charged by connecting to the power grid through a power adapter. In practical applications, the time when electronic products are charged by connecting to the power grid through a power adapter is relatively short. Most of the time, the power adapter is not connected to the load. When the power adapter is not connected to the load, the isolated power supply circuit in the power adapter still needs to adjust the output voltage of the power adapter so that the power adapter can charge the connected load at any time.

[0052] Since the circuit for adjusting the output voltage in the isolated power supply circuit is always in a working state, the power adapter consumes a lot of energy. Therefore, the isolated power supply circuit in the related art additionally introduces a load detection signal transmission unit.

[0053] Reference Figure 1 , Figure 1 FIG. 1 is a schematic diagram of the structure of an isolated power supply circuit in the related art. Figure 1 As shown, the isolated power supply circuit in the related art may include: a secondary control unit, a load detection unit, an output hysteresis control unit, a load detection signal transmission unit, a main side drive signal transmission unit and a primary control unit. The load detection unit can detect whether the isolated power supply circuit is connected to the load, that is, the load detection unit can detect whether the power adapter is connected to the load. When the load detection unit detects that the power adapter is in a state where the load is not connected, the load detection unit can transmit an indication signal to the secondary control unit so that the secondary control unit can enter a low power consumption mode. At the same time, the load detection unit transmits the indication signal to the primary control unit located on the primary side of the isolated power supply circuit through the load detection signal transmission unit. In this way, after receiving the indication signal, the primary control unit no longer adjusts the output voltage with high precision, but turns off most of the circuits in the primary control unit, so that the primary control unit enters a low power consumption mode, and the isolated power supply circuit enters a low power consumption mode. Thereby, the energy consumption of the power adapter can be reduced.

[0054] However, the introduction of the load detection signal transmission unit increases the cost of the isolated power supply circuit, thereby increasing the cost of the power adapter.

[0055] In addition, when the isolated power supply circuit is in low power consumption mode, the primary control unit adjusts the output voltage with low precision. In other words, the isolated power supply circuit still needs to adjust the output voltage, and the output voltage needs to be kept near the preset voltage value so that the isolated power supply circuit can work normally at any time. Usually, the isolated power supply circuit uses hysteresis control to adjust the output voltage. Specifically, an output hysteresis control unit is additionally introduced on the secondary side of the isolated power supply circuit to detect the output voltage.

[0056] When the output voltage is less than the threshold voltage Voth1, the output hysteresis control unit transmits a signal through the main side drive signal transmission unit, so that the primary control unit periodically turns on the power tube, until the output voltage is greater than the threshold voltage Voth2, the output hysteresis control unit transmits a signal through the main side drive signal transmission unit, so that the primary control unit turns off the power tube. This process is repeated repeatedly, and it is possible to avoid using the loop regulation circuit in the primary control unit to ensure that the output voltage is stable near the preset voltage value, so as to save power consumption. Therefore, when the output voltage is stable near the preset voltage value, the isolated power supply circuit can work at any time after the load is reconnected, so that the power adapter can work normally.

[0057] However, since the output hysteresis control unit and the primary side drive signal transmission unit need to be started all the time, the primary control unit can turn on the power tube in time when the output voltage is less than the threshold voltage Voth1. Therefore, the power consumption of the output hysteresis control unit and the primary side drive signal transmission unit increases the power consumption of the isolated power supply circuit in the low power consumption mode.

[0058] To this end, the present application provides an isolated power supply circuit, an isolated power supply, a control method, a chip and an electronic device.

[0059] Wherein, the isolated power supply may include: an isolated power supply circuit.

[0060] The isolated power supply circuit and the isolated power supply may be a chip or a circuit module.

[0061] In some examples, the isolated power supply is a power adapter.

[0062] In this application, electronic equipment may include, but is not limited to: medical equipment, smart home, automotive electronics, security monitoring equipment, and laboratory equipment.

[0063] Reference Figure 2 , Figure 2 This is a schematic diagram of the structure of an isolated power supply circuit provided by an embodiment of the present application. Figure 2 As shown, the isolated power supply circuit 100 may include: a primary power loop 110 , a primary control circuit 160 , a power transformer 120 , a secondary control circuit 130 , a load detection circuit 140 and an optocoupler element 150 .

[0064] A first end of the primary power circuit 110 is electrically connected to a first end of the power transformer 120, a second end of the primary power circuit 110 is electrically connected to a first end of the primary control circuit 160, a second end of the primary control circuit 160 is electrically connected to an output end of the optocoupler element 150, a third end of the primary control circuit 160 is electrically connected to a third end of the primary power circuit 110, a first end of the secondary control circuit 130 is electrically connected to a second end of the power transformer 120, a second end of the secondary control circuit 130 is electrically connected to a first end of the load detection circuit 140 and an input end of the optocoupler element 150, respectively, a second end of the secondary control circuit 130 is also used as an output end of the isolated power supply circuit 100, a third end of the secondary control circuit 130 is electrically connected to a second end of the load detection circuit 140, and a fourth end of the secondary control circuit 130 is electrically connected to a control end of the optocoupler element 150.

[0065] The primary power circuit 110 , the primary control circuit 160 , the power transformer 120 , the secondary control circuit 130 , the load detection circuit 140 and the optical coupling element 150 may be arranged separately or integrated.

[0066] The primary power circuit 110 and the primary control circuit 160 are located on the primary side of the isolated power circuit 100 . The secondary control circuit 130 , the load detection circuit 140 and the optical coupler 150 are located on the secondary side of the isolated power circuit 100 .

[0067] Figure 2 In the figure, the first end of the primary power circuit 110 is marked as 1, the second end of the primary power circuit 110 is marked as 2, the third end of the primary power circuit 110 is marked as 3, the first end of the power transformer 120 is marked as 1, the second end of the power transformer 120 is marked as 2, the output end of the optocoupler 150 is marked as 1, the input end of the optocoupler 150 is marked as 2, and the control end of the optocoupler 150 is marked as 3.

[0068] Below, refer to Figure 3 , Figure 3 A flow chart of a control method provided in one embodiment of the present application is shown in FIG. Figure 3 As shown, the method includes:

[0069] S101. A load detection circuit transmits a first signal to the secondary control circuit.

[0070] The first signal is used to indicate whether the isolated power supply circuit is connected to a load.

[0071] S102. When the first signal indicates that the isolated power supply circuit is not connected to a load, the secondary control circuit pulls down the voltage at the output end of the optocoupler element, and after a preset time, turns off the optocoupler element to increase the voltage at the output end of the optocoupler element, and pulls down the output voltage of the isolated power supply circuit within the preset time.

[0072] After the optocoupler element is turned off, the secondary control circuit enters a low power consumption mode.

[0073] S103 , when the voltage at the output end of the optocoupler element increases, the primary control circuit transmits a second signal to the primary power loop.

[0074] The second signal is used to indicate the primary power circuit to detect changes in the output voltage of the isolated power supply circuit.

[0075] S104, after receiving the second signal, the primary power circuit detects through the power transformer whether the output voltage of the isolation power circuit is pulled down, obtains a third signal, and transmits the third signal to the primary control circuit.

[0076] S105 . When the primary control circuit detects that the output voltage of the isolated power supply circuit is pulled low according to the third signal, the primary control circuit enters a low power consumption mode, so that the isolated power supply circuit enters a low power consumption mode.

[0077] In some examples, the method further includes: when the first signal indicates that the isolated power supply circuit is connected to the load, the secondary control circuit exits the low power mode and pulls down the voltage at the output end of the optocoupler element. When the primary control circuit detects that the voltage at the output end of the optocoupler element is pulled down, the low power mode is exited.

[0078] The load detection circuit 140 may transmit the first signal CC Detect to the secondary control circuit 130 , so that the secondary control circuit 130 may obtain the first signal CC Detect.

[0079] The first signal CC Detect is used to indicate whether the isolated power supply circuit 100 is connected to a load.

[0080] When the first signal CC Detect indicates that the isolated power supply circuit 100 is not connected to a load, the secondary control circuit 130 can pull down the voltage VFB at the output end of the optocoupler element 150, and after a preset time, turn off the optocoupler element 150 to increase the voltage VFB at the output end of the optocoupler element 150, so that the primary control circuit 160 can detect the change of the voltage VFB at the output end of the optocoupler element 150. At the same time, within the preset time, the secondary control circuit 130 can pull down the output voltage Vo of the isolated power supply circuit 100.

[0081] After the optocoupler element 150 is turned off, the secondary control circuit 130 may enter a low power consumption mode. In the low power consumption mode, some circuits in the secondary control circuit 130 are in a non-operating state.

[0082] In this way, when the voltage VFB at the output terminal of the optical coupling element 150 increases, the primary control circuit 160 can transmit the second signal DRV to the primary power circuit 110 , so that the primary power circuit 110 can obtain the second signal DRV.

[0083] The second signal DRV is used to instruct the primary power circuit 110 to detect changes in the output voltage Vo of the isolated power supply circuit 100 .

[0084] In this way, after receiving the second signal DRV, the primary power circuit 110 can detect whether the output voltage Vo of the isolation power supply circuit 100 is pulled down through the power transformer 120 to obtain the third signal Vo_sen. In addition, the primary power circuit 110 can transmit the third signal Vo_sen to the primary control circuit 160, so that the primary control circuit 160 can obtain the third signal Vo_sen.

[0085] Furthermore, the primary control circuit 160 can enter a low power mode when it detects that the output voltage Vo of the isolated power supply circuit 100 is pulled down according to the third signal Vo_sen. In this way, after both the secondary control circuit 130 and the primary control circuit 160 enter the low power mode, the isolated power supply circuit 100 enters the low power mode. Due to the optical coupling element 150, the primary control circuit can detect the change of the voltage VFB at the output end of the optical coupling element 150. In other words, the isolated power supply circuit 100 communicates between the primary side and the secondary side through the optical coupling element 150. Therefore, the use of the load detection signal transmission unit in the related art can be avoided. Thereby, the cost of the isolated power supply circuit 100 can be reduced, as well as the cost of the power adapter.

[0086] In the low power consumption mode, the primary control circuit 160 turns off almost all circuits in the primary control circuit 160, leaving only the basic circuits such as the power supply circuit and the output voltage regulation circuit to work, so that the primary control circuit 160 can perform low-precision regulation on the output voltage Vo.

[0087] In some examples, when the first signal CC Detect indicates that the isolated power supply circuit 100 is connected to a load, the secondary control circuit 130 may exit the low power mode and the secondary control circuit 130 may pull down the voltage VFB at the output end of the optocoupler element 150 .

[0088] Thus, when the voltage VFB at the output end of the optocoupler 150 is detected to be pulled down, the primary control circuit 160 can exit the low power mode. Thus, the isolated power supply circuit 100 can work normally and can adjust the output voltage Vo with high precision.

[0089] The isolated power supply circuit, isolated power supply, control method, chip and electronic device provided by the present application can transmit a first signal to the secondary control circuit to indicate whether the isolated power supply circuit is connected to the load through the load detection circuit, so that the secondary control circuit can obtain the first signal. When the first signal indicates that the isolated power supply circuit is not connected to the load, the secondary control circuit can pull down the voltage at the output end of the optocoupler element, and after a preset time, turn off the optocoupler element, so that the voltage at the output end of the optocoupler element increases, and after the optocoupler element is turned off, the secondary control circuit can enter a low power consumption mode. At the same time, within the preset time, the secondary control circuit can pull down the output voltage of the isolated power supply circuit. In this way, when the voltage at the output end of the optocoupler element increases, the primary control circuit can transmit a second signal to the primary power circuit to indicate the change of the output voltage of the isolated power supply circuit detected by the primary power circuit, so that the primary power circuit can obtain the second signal. In this way, after receiving the second signal, the primary power circuit can detect whether the output voltage of the isolated power supply circuit is pulled down through the power transformer to obtain a third signal. In addition, the primary power circuit can transmit a third signal to the primary control circuit, so that the primary control circuit can obtain the third signal. Furthermore, the primary control circuit can enter a low power mode when it detects that the output voltage of the isolated power supply circuit is pulled down according to the third signal, so that the isolated power supply circuit enters a low power mode. Since the secondary side of the isolated power supply circuit communicates with the primary side of the isolated power supply circuit through an optical coupling element, it is possible to avoid additionally introducing a load detection signal transmission unit in the related art. Thus, the cost of the isolated power supply circuit and the cost of the power adapter can be reduced.

[0090] Based on the description of the above embodiment, a possible implementation of the optical coupling element 150 is exemplified. Figure 4 , Figure 4 Shows Figure 2 The structural diagram of the isolated power supply circuit is shown in Figure 1. Figure 4 As shown, the optical coupling element 150 may include: an optical coupler 151 .

[0091] The first end of the optocoupler 151 is electrically connected to the second end of the secondary control circuit 130, the second end of the optocoupler 151 is electrically connected to the second end of the primary control circuit 160, the third end of the optocoupler 151 is electrically connected to the ground end of the secondary side of the isolated power supply circuit 100, the fourth end of the secondary control circuit 130 is electrically connected between the third end of the optocoupler 151 and the ground end of the secondary side of the isolated power supply circuit 100, and the fourth end of the optocoupler 151 is electrically connected to the ground end of the primary side of the isolated power supply circuit 100.

[0092] Figure 2 and Figure 4In the figure, the first end of the primary control circuit 160 is recorded as 1, the second end of the primary control circuit 160 is recorded as 2, the third end of the primary control circuit 160 is recorded as 3, the fourth end of the primary control circuit 160 is recorded as 4, the first end of the secondary control circuit 130 is recorded as 1, the second end of the secondary control circuit 130 is recorded as 2, the third end of the secondary control circuit 130 is recorded as 3, the fourth end of the secondary control circuit 130 is recorded as 4, the first end of the load detection circuit 140 is recorded as 1, and the second end of the load detection circuit 140 is recorded as 2.

[0093] After the preset time, the secondary control circuit 130 turns off the optical coupler 151. Thus, under the action of the turned-off optical coupler 151, the voltage at the first end of the optical coupler 151 increases. Then, the optical coupler 150 turns off, causing the voltage VFB at the output end of the optical coupler 150 to increase. Thus, after the preset time, the secondary control circuit 150 can turn off the optical coupler 150, causing the voltage VFB at the output end of the optical coupler 150 to increase.

[0094] In some examples, when the isolated power supply circuit 100 exits the low power consumption mode, the optocoupler element 150 may further include: a voltage regulator tube 152 , a fourth resistor R4 , and a fifth resistor R5 .

[0095] The third end of the optocoupler 151 is electrically connected to the first end of the Zener diode 152, the first end of the fourth resistor R4 is electrically connected to the second end of the secondary control circuit 130, the second end of the fourth resistor R4 is electrically connected to the first end of the fifth resistor R5, the third end of the Zener diode 152 is electrically connected between the second end of the fourth resistor R4 and the first end of the fifth resistor R5, and the second end of the fifth resistor R5 and the second end of the Zener diode 152 are both electrically connected to the ground terminal of the secondary side of the isolation power supply circuit 100.

[0096] When the isolated power supply circuit 100 exits the low power consumption mode, that is, when the isolated power supply circuit 100 is in a normal state, the optical coupling element 150 can play a role in loop regulation.

[0097] In summary, after a preset time period, the secondary control circuit can turn off the optical coupler to turn off the optical coupling element. Thus, the secondary control circuit can turn off the optical coupling element.

[0098] Based on the description of the above embodiment, a possible implementation of the primary power circuit 110 is exemplified. Figure 4 As shown, the primary power circuit 110 may include: a third signal output module 111, a primary switch tube Q, a first resistor R1 and a first capacitor C1.

[0099] The first end of the first capacitor C1 is electrically connected to the first end of the auxiliary winding in the power transformer 120, the fourth end of the primary control circuit 160 is electrically connected between the first end of the first capacitor C1 and the first end of the auxiliary winding in the power transformer 120, the input end of the third signal output module 111 is electrically connected between the first end of the first capacitor C1 and the first end of the auxiliary winding in the power transformer 120, the output end of the third signal output module 111 is electrically connected to the first end of the primary control circuit 160, the first end of the primary switch tube Q is electrically connected to the primary winding in the power transformer 120, the control end of the primary switch tube Q is electrically connected to the third end of the primary control circuit 160, the second end of the primary switch tube Q is electrically connected to the first end of the first resistor R1, and the second end of the first resistor R1, the second end of the first capacitor C1, the second end of the auxiliary winding and the ground end of the third signal output module 111 are all electrically connected to the ground end of the primary side of the isolation power supply circuit 100.

[0100] After receiving the second signal DRV, the primary switch tube Q is turned on to store energy in the primary winding of the power transformer 120. In this way, the primary winding in the power transformer 120 can release energy to the auxiliary winding in the power transformer 120 and the secondary winding in the power transformer 120, respectively, so that the change in the voltage at the input end of the third signal output module 111 is related to the change in the output voltage Vo of the isolated power supply circuit 100. In this way, the third signal output module 111 can couple the output voltage Vo of the isolated power supply circuit 100 through the power transformer 120 to detect whether the output voltage Vo of the isolated power supply circuit 100 is pulled down. Furthermore, the three-signal output module 111 can generate a third signal Vo_sen. Thus, the primary power circuit 110 can obtain the third signal Vo_sen.

[0101] Wherein, the primary control circuit 160 transmits the second signal DRV to the primary power circuit 110 several times, and the primary power circuit 110 can detect whether the output voltage Vo of the isolated power circuit 100 is pulled down several times through the power transformer 120. For example, if the primary control circuit 160 transmits the second signal DRV to the primary power circuit 110 three times, the primary power circuit 110 detects whether the output voltage Vo of the isolated power circuit 100 is pulled down three times through the power transformer 120. In order to ensure accuracy, the primary control circuit 160 can transmit the second signal DRV to the primary power circuit 110 multiple times.

[0102] In summary, after receiving the second signal, the primary switch tube is turned on to charge the primary winding in the power transformer. In this way, the primary winding in the power transformer releases energy to the auxiliary winding in the power transformer and the secondary winding in the power transformer respectively, so that the change in the voltage at the input end of the third signal output module is related to the change in the output voltage of the isolated power supply circuit. In this way, the third signal output module can couple the output voltage of the isolated power supply circuit through the power transformer to detect whether the output voltage of the isolated power supply circuit is pulled down. Furthermore, the third signal output module can generate a third signal. Thus, the primary power circuit can obtain the third signal.

[0103] Based on the description of the above embodiment, a possible implementation of the third signal output module 111 is exemplified. Figure 4 As shown, the third signal output module 111 may include: a second resistor R2 and a third resistor R3.

[0104] A first end of the second resistor R2 is electrically connected between a first end of the first capacitor C1 and a first end of an auxiliary winding in the power transformer 120, a second end of the second resistor R2 is electrically connected to a first end of the second resistor R2, a first end of the primary control circuit 160 is electrically connected between a second end of the second resistor R2 and a first end of a third resistor R3, and a second end of the third resistor R3 is electrically connected to a ground terminal on a primary side of the isolated power supply circuit 100.

[0105] The third signal output module 111 can generate the third signal Vo_sen through the voltage division of the second resistor R2 and the third resistor R3 .

[0106] In summary, through the voltage division of the second resistor and the third resistor, the third signal output module can generate the third signal.

[0107] When the isolated power supply circuit 100 enters the low power consumption mode, the output voltage Vo of the isolated power supply circuit 100 is discharged only through the leakage current of the secondary side of the isolated power supply circuit 100, so that the discharge slope of the output voltage Vo of the isolated power supply circuit 100 is very low. Since the primary switch tube Q is turned off, the voltage VDD at the fourth terminal of the primary control circuit 160, that is, the power supply rail of the primary control circuit 160, is discharged only through the basic working circuit in the primary control circuit 160.

[0108] The discharge slope of the voltage VDD at the fourth terminal of the primary control circuit 160 is related to the capacitance of the first capacitor C1. When the capacitance of the first capacitor C1 is larger, the discharge slope of the voltage VDD at the fourth terminal of the primary control circuit 160 is slower. When the capacitance of the first capacitor C1 is smaller, the discharge slope of the voltage VDD at the fourth terminal of the primary control circuit 160 is faster.

[0109] Since the isolated power supply circuit 100 still needs to adjust the output voltage Vo with low precision. Figure 5 , Figure 5 This is a flow chart of an isolated power supply circuit regulating output voltage provided in an embodiment of the present application. It describes in detail how to regulate the output voltage Vo when the isolated power supply circuit 100 enters a low power consumption mode. The content is as follows:

[0110] When the isolated power supply circuit 100 enters the low power consumption mode, that is, when the primary control circuit 160 enters the low power consumption mode, when the voltage VDD at the fourth terminal of the primary control circuit 160 is lower than the first threshold voltage VDDth1, the primary control circuit 160 can control the primary switch tube Q to be turned on, so that the primary winding in the power transformer 120 stores energy. In this way, the primary winding in the power transformer 120 releases energy to the auxiliary winding in the power transformer 120 and the secondary winding in the power transformer 120, respectively, so that the voltage VDD at the fourth terminal of the primary control circuit 160 and the output voltage Vo of the isolated power supply circuit 100 are both increased.

[0111] Since the primary control circuit 160 has entered the low power consumption mode, the primary control circuit 160 consumes very little current from the voltage VDD at the fourth terminal of the primary control circuit 160. Therefore, the voltage VDD at the fourth terminal of the primary control circuit 160 rises very quickly.

[0112] When the voltage VDD at the fourth terminal of the primary control circuit 160 increases to the second threshold voltage VDDth2, the primary control circuit 160 can control the primary switch tube Q to turn off, so that the voltage VDD at the fourth terminal of the primary control circuit 160 and the output voltage Vo of the isolated power supply circuit 100 are both in a slow discharge stage. Thus, the output voltage Vo of the isolated power supply circuit 100 can be stabilized within a preset voltage range.

[0113] In some examples, the preset voltage range is related to the first threshold voltage VDDth1 , the second threshold voltage VDDth2 , and a turns ratio between the secondary winding of the power transformer 120 and the auxiliary winding of the power transformer 120 .

[0114] The lower limit voltage value Vo1 of the preset voltage range can be determined by the first threshold voltage VDDth1 and the turns ratio, and the upper limit voltage value Vo2 of the preset voltage range can be determined by the second threshold voltage VDDth2 and the turns ratio.

[0115] When the primary control circuit 160 is in a stable low power consumption mode, the voltage VDD at the fourth terminal of the primary control circuit 160 will change between the first threshold voltage VDDth1 and the second threshold voltage VDDth2. In this way, the output voltage Vo is always stable within the preset voltage range, that is, the output voltage Vo changes between the lower limit voltage value Vo1 of the preset voltage range and the upper limit voltage value Vo2 of the preset voltage range. By setting the turns ratio between the secondary winding and the auxiliary winding, the output voltage Vo is maintained within the expected preset voltage range.

[0116] Among them, since the discharge slope of the voltage VDD at the fourth terminal of the primary control circuit 160 is related to the capacitance of the first capacitor C1. Therefore, the time length for the voltage VDD at the fourth terminal of the primary control circuit 160 to rise from the first threshold voltage VDDth1 to the second threshold voltage VDDth2 is related to the capacitance of the first capacitor C1. When the capacitance of the first capacitor C1 is large, the time length for the voltage VDD at the fourth terminal of the primary control circuit 160 to rise from the first threshold voltage VDDth1 to the second threshold voltage VDDth2 is longer. When the capacitance of the first capacitor C1 is small, the time length for the voltage VDD at the fourth terminal of the primary control circuit 160 to rise from the first threshold voltage VDDth1 to the second threshold voltage VDDth2 is shorter.

[0117] Since the primary winding in the power transformer 120 releases energy to the auxiliary winding in the power transformer 120 and the secondary winding in the power transformer 120 respectively, the change of the voltage VDD at the fourth terminal of the primary control circuit 160 is related to the change of the output voltage Vo. In this way, the primary control circuit 160 can detect the change of the output voltage Vo by the change of the voltage VDD at the fourth terminal of the primary control circuit 160. In this way, the primary control circuit 160 can control the periodic conduction of the primary switch tube Q to adjust the voltage VDD at the fourth terminal of the primary control circuit 160. Furthermore, the primary control circuit 160 can adjust the output voltage Vo, which can avoid the use of the output hysteresis control unit and the primary side drive signal transmission unit in the related art. Thereby, the energy consumption of the isolated power supply circuit 100 can be reduced, and the energy consumption of the power adapter can be reduced.

[0118] At the same time, the primary control circuit 160 adjusts the voltage VDD of the fourth terminal of the primary control circuit 160, which can complete the power supply control of the primary control circuit 160 in the low power consumption mode, and can improve the energy utilization efficiency of the primary control circuit 160 in the low power consumption mode.

[0119] Next, combine Figure 6 , Figure 6 Shows Figure 2 and Figure 4The working waveform diagram of the isolated power supply circuit is shown in FIG. The working principle of the isolated power supply circuit 100 is introduced in detail.

[0120] During the period t0-t1, the isolated power supply circuit 100 is in a normal startup state. During this period, the isolated power supply circuit 100 performs soft start and no-load regulation.

[0121] At time t1, the load detection circuit 140 detects that the isolated power supply circuit 100 is in a state of not being connected to a load, and the load detection circuit 140 can transmit a first signal CC Detect to the secondary control circuit 130, so that the secondary control circuit 130 can pull down the voltage VFB at the output end of the optocoupler element 150. At this moment, the first signal CC Detect is at a low level.

[0122] During the period t1-t3, the voltage VFB at the output end of the optical coupling element 150 is always in a pulled-down state, that is, the duration of this period is a preset duration. At time t2, the secondary control circuit 130 can pull down the output voltage Vo of the isolated power supply circuit 100.

[0123] At time t3, the secondary control circuit 130 can turn off the optocoupler element 150, so that the voltage VFB at the output end of the optocoupler element 150 increases, so that the primary control circuit 160 can detect the change of the voltage VFB at the output end of the optocoupler element 150. At this time, the primary control circuit 160 can transmit the second signal DRV to the primary power circuit 110, so that the primary power circuit 110 can detect whether the output voltage Vo of the isolated power supply circuit 100 is pulled down, and obtain the third signal Vo_sen, wherein after the optocoupler element 150 is turned off, the secondary control circuit 130 enters the low power consumption mode.

[0124] During the period t3-t4, the primary control circuit 160 may transmit the second signal DRV twice to the primary power loop 110 to turn on the primary switch tube Q. Meanwhile, reliability can be ensured.

[0125] At time t4, the primary control circuit 160 can detect that the output voltage Vo of the isolated power supply circuit 100 is pulled down according to the third signal Vo_sen. In this way, the primary control circuit 160 enters the low power consumption mode, so that the isolated power supply circuit 100 enters the low power consumption mode.

[0126] During the period t4-t5, the isolated power supply circuit 100 is in a low power consumption mode. During this period, the isolated power supply circuit 100 adjusts the output voltage Vo with low precision.

[0127] At time t5, when it is detected that the isolated power supply circuit 100 is in a state of being connected to a load, the load detection circuit 140 can transmit the first signal CC Detect to the secondary control circuit 130, so that the secondary control circuit 130 can exit the low power mode and pull down the voltage VFB at the output end of the optocoupler element 150. In this way, when it is detected that the voltage VFB at the output end of the optocoupler element 150 is pulled down, the primary control circuit 160 can exit the low power mode, so that the isolated power supply circuit 100 can work normally. At this moment, the first signal CC Detect is at a high level.

[0128] Figure 6 In the figure, DRV represents the second signal, Vo represents the output voltage of the isolated power supply circuit 100, CC Detect represents the first signal, VFB represents the voltage at the output end of the optocoupler element 150, and Hiber represents the working mode of the primary control circuit 160. When Hiber is at a low level, the primary control circuit 160 is in a normal working state, and when Hiber is at a high level, the primary control circuit 160 is in a low power consumption mode.

[0129] Next, combine Figure 7 , Figure 7 Shows Figure 2 and Figure 4 The working principle of the isolated power supply circuit 100 in the low power consumption mode is introduced in detail.

[0130] During the period T1, the voltage VDD at the fourth terminal of the primary control circuit 160 slowly decreases from the second threshold voltage VDDth2 to the first threshold voltage VDDth1. During this period, the output voltage Vo of the isolation power supply circuit 100 slowly decreases from the upper limit voltage value Vo2 of the preset voltage range to the lower limit voltage value Vo1 of the preset voltage range.

[0131] During the T2 period, when the voltage VDD at the fourth terminal of the primary control circuit 160 is lower than the first threshold voltage VDDth1, the primary control circuit 160 may transmit a signal PDRV to the primary switch tube Q to turn on the primary switch tube Q. In this way, the primary winding in the power transformer 120 releases energy to the auxiliary winding in the power transformer 120 and the secondary winding in the power transformer 120, respectively, so that the voltage VDD at the fourth terminal of the primary control circuit 160 and the output voltage Vo of the isolated power supply circuit 100 both increase, until the voltage VDD at the fourth terminal of the primary control circuit 160 increases to the second threshold voltage VDDth2, so that the output voltage Vo of the isolated power supply circuit 100 increases to the upper limit voltage value Vo2 of the preset voltage range.

[0132] After the T2 period, the primary control circuit 160 stops transmitting the signal PDRV to the primary switch tube Q, so that the voltage VDD at the fourth terminal of the primary control circuit 160 and the output voltage Vo of the isolation power circuit 100 change in the same manner as in the T1 period.

[0133] Finally, it should be noted that the above embodiments are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto, and any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An isolated power supply circuit, characterized in that: The isolated power supply circuit includes: a primary power loop, a primary control circuit, a power transformer, a secondary control circuit, a load detection circuit and an optical coupling element; The first end of the primary power circuit is electrically connected to the first end of the power transformer, the second end of the primary power circuit is electrically connected to the first end of the primary control circuit, the second end of the primary control circuit is electrically connected to the output end of the optocoupler element, the third end of the primary control circuit is electrically connected to the third end of the primary power circuit, the first end of the secondary control circuit is electrically connected to the second end of the power transformer, the second end of the secondary control circuit is electrically connected to the first end of the load detection circuit and the input end of the optocoupler element respectively, the second end of the secondary control circuit is also used as the output end of the isolated power supply circuit, the third end of the secondary control circuit is electrically connected to the second end of the load detection circuit, and the fourth end of the secondary control circuit is electrically connected to the control end of the optocoupler element; The load detection circuit is used to transmit a first signal to the secondary control circuit, wherein the first signal is used to indicate whether the isolated power supply circuit is connected to a load; The secondary control circuit is used to pull down the voltage at the output end of the optocoupler element when the first signal indicates that the isolated power supply circuit is not connected to a load, and turn off the optocoupler element after a preset time period, so that the voltage at the output end of the optocoupler element increases, and pull down the output voltage of the isolated power supply circuit within the preset time period, wherein after the optocoupler element is turned off, the secondary control circuit enters a low power consumption mode; The primary control circuit is used to transmit a second signal to the primary power circuit when the voltage at the output end of the optical coupling element increases, and the second signal is used to instruct the primary power circuit to detect the change of the output voltage of the isolated power supply circuit; The primary power circuit is used to detect whether the output voltage of the isolation power supply circuit is pulled down through the power transformer after receiving the second signal, obtain a third signal, and transmit the third signal to the primary control circuit; The primary control circuit is further configured to enter the low power consumption mode when it is detected, based on the third signal, that the output voltage of the isolated power supply circuit is pulled low, so that the isolated power supply circuit enters the low power consumption mode.

2. The circuit according to claim 1, characterized in that The secondary control circuit is further configured to exit the low power consumption mode and lower the voltage at the output end of the optocoupler element when the first signal indicates that the isolated power supply circuit is connected to a load; The primary control circuit is further configured to exit the low power consumption mode when it is detected that the voltage at the output end of the optocoupler element is pulled low.

3. The circuit according to claim 2, characterized in that The optical coupling element comprises: an optical coupler; The first end of the optocoupler is electrically connected to the second end of the secondary control circuit, the second end of the optocoupler is electrically connected to the second end of the primary control circuit, the third end of the optocoupler is electrically connected to the ground end of the secondary side of the isolated power supply circuit, the fourth end of the secondary control circuit is electrically connected between the third end of the optocoupler and the ground end of the secondary side of the isolated power supply circuit, and the fourth end of the optocoupler is electrically connected to the ground end of the primary side of the isolated power supply circuit.

4. The circuit according to any one of claims 1 to 3, characterized in that: The primary power circuit includes: a third signal output module, a primary switch tube, a first resistor and a first capacitor; The first end of the first capacitor is electrically connected to the first end of the auxiliary winding in the power transformer, the fourth end of the primary control circuit is electrically connected between the first end of the first capacitor and the first end of the auxiliary winding in the power transformer, the input end of the third signal output module is electrically connected between the first end of the first capacitor and the first end of the auxiliary winding in the power transformer, the output end of the third signal output module is electrically connected to the first end of the primary control circuit, the first end of the primary switch tube is electrically connected to the primary winding in the power transformer, the control end of the primary switch tube is electrically connected to the third end of the primary control circuit, the second end of the primary switch tube is electrically connected to the first end of the first resistor, and the second end of the first resistor, the second end of the first capacitor, the second end of the auxiliary winding and the ground end of the third signal output module are all electrically connected to the ground end of the primary side of the isolation power supply circuit; The third signal output module is used to generate the third signal by coupling the output voltage of the isolation power supply circuit through the power transformer.

5. The circuit according to claim 4, characterized in that The third signal output module includes: a second resistor and a third resistor; The first end of the second resistor is electrically connected between the first end of the first capacitor and the first end of the auxiliary winding in the power transformer, the second end of the second resistor is electrically connected to the first end of the third resistor, the first end of the primary control circuit is electrically connected between the second end of the second resistor and the first end of the third resistor, and the second end of the second resistor is electrically connected to the ground terminal of the primary side of the isolated power supply circuit.

6. The circuit according to claim 4, characterized in that The primary control circuit is also used to control the primary switch tube to turn on when the voltage at the fourth terminal of the primary control circuit is lower than the first threshold voltage when the isolated power supply circuit enters the low power consumption mode, so that the voltage at the fourth terminal of the primary control circuit increases until the voltage at the fourth terminal of the primary control circuit increases to the second threshold voltage, and control the primary switch tube to turn off so that the output voltage of the isolated power supply circuit is within a preset voltage range.

7. The circuit according to claim 6, characterized in that The preset voltage range is related to the first threshold voltage, the second threshold voltage, and a turns ratio between the secondary winding of the power transformer and the auxiliary winding of the power transformer.

8. The circuit according to claim 6, characterized in that The time length for the voltage at the fourth terminal of the primary control circuit to rise from the first threshold voltage to the second threshold voltage is related to the capacitance of the first capacitor.

9. An isolated power supply, characterized in that: include: An isolated power supply circuit as claimed in any one of claims 1 to 8.

10. A control method, characterized in that: The method is applied to the isolated power supply circuit according to any one of claims 1 to 8 or to the isolated power supply according to claim 8, and the method comprises: The load detection circuit transmits a first signal to the secondary control circuit, where the first signal is used to indicate whether the isolated power supply circuit is connected to a load; When the first signal indicates that the isolated power supply circuit is not connected to a load, the secondary control circuit pulls down the voltage at the output end of the optocoupler element, and after a preset time, turns off the optocoupler element, so that the voltage at the output end of the optocoupler element increases, and within the preset time, pulls down the output voltage of the isolated power supply circuit, wherein after the optocoupler element is turned off, the secondary control circuit enters a low power consumption mode; When the voltage at the output end of the optical coupling element increases, the primary control circuit transmits a second signal to the primary power circuit, wherein the second signal is used to instruct the primary power circuit to detect a change in the output voltage of the isolated power supply circuit; After receiving the second signal, the primary power circuit detects whether the output voltage of the isolation power supply circuit is pulled down through the power transformer to obtain a third signal, and transmits the third signal to the primary control circuit; When the primary control circuit detects, based on the third signal, that the output voltage of the isolated power supply circuit is pulled low, the primary control circuit enters the low power consumption mode, so that the isolated power supply circuit enters the low power consumption mode.

11. The control method according to claim 10, characterized in that: The method further comprises: When the first signal indicates that the isolated power supply circuit is connected to a load, the secondary control circuit exits the low power consumption mode and pulls down the voltage at the output end of the optocoupler element; When the primary control circuit detects that the voltage at the output end of the optocoupler element is pulled low, the primary control circuit exits the low power consumption mode.

12. A chip, characterized in that: include: An isolated power supply circuit as claimed in any one of claims 1 to 8, or an isolated power supply as claimed in claim 9.

13. An electronic device, characterized in that: include: The chip as claimed in claim 12.

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