Power supply circuits and charging equipment

Abstract

This invention discloses a power supply circuit and a charging device. The power supply circuit includes: a transformer, a primary circuit connected to the primary winding of the transformer, a secondary circuit connected to the first and second windings of the transformer, an isolation module, and a control module. The control module is connected to the transmitting end of the secondary circuit and the isolation module, and the receiving end of the isolation module is connected to the switching transistor of the primary circuit. The control module generates a first switching control signal based on the output voltage of the secondary circuit and transmits it to the switching transistor of the primary circuit through the isolation module to control the switching of the primary circuit. In this circuit, the isolation module enables direct control of the primary side from the secondary side, eliminating the need for a PWM controller on the primary side, effectively reducing the size of the power supply circuit. It also eliminates the signal conversion process caused by optocoupler feedback, resulting in higher timeliness.

Description

Power Circuit and Charging Device This invention claims the priority of the Chinese patent application with the application number 202311206459.2 and the application title "Power Circuit and Charging Device" submitted to the Chinese Patent Office on September 18, 2023. The entire content is incorporated into this invention by reference. This invention relates to the field of power supply technology, and particularly to a power circuit and a charging device. With the increasingly wide application scope of electronic devices, the requirement for the thinness and lightness of electronic devices is also getting higher and higher, which also restricts the requirement for the volume of the power circuit structure of electronic devices to be getting higher and higher. In related technologies, a flyback conversion circuit is used to achieve fast charging of electronic devices. In this circuit, an output voltage detection circuit is arranged on the secondary side to detect the output voltage of the secondary side, and the detected voltage is transmitted to the PWM controller on the primary side through an optocoupler. The PWM controller controls the switching tube on the primary side, thereby realizing the adjustment of the output voltage on the primary side to achieve the purpose of fast charging. However, this control of the primary side and the secondary side through the optocoupler feedback loop not only requires the use of more components, resulting in a large volume of the power circuit, but also has poor control timeliness. This invention aims to solve at least one of the technical problems in related technologies to some extent. For this purpose, the first object of this invention is to propose a power circuit, which transmits the first switch control signal to the switching tube of the primary circuit through an isolation module to control the switching tube of the primary circuit, realizing direct control of the primary side by the secondary side, eliminating the PWM controller on the primary side, effectively reducing the volume of the power circuit, and at the same time eliminating the signal conversion process brought by optocoupler feedback, with high timeliness. The second object of this invention is to propose a charging device. To achieve the above object, an embodiment of the first aspect of this invention proposes a power circuit, including: a transformer, a primary circuit connected to the primary winding of the transformer, a secondary circuit connected to the first secondary winding of the transformer, an isolation module, and a control module. The control module is connected to the secondary circuit and the transmitting end of the isolation module, and the receiving end of the isolation module is connected to the switching tube of the primary circuit. Among them, the control module is used to generate a first switch control signal based on the output voltage of the secondary circuit and transmit it to the switching tube of the primary circuit through the isolation module to perform switch control on the switching tube of the primary circuit. According to the power circuit of the embodiment of this invention, the first switch control signal is transmitted to the switching tube of the primary circuit through the isolation module to control the switching tube of the primary circuit, realizing direct control of the primary side by the secondary side, eliminating the PWM controller on the primary side, effectively reducing the volume of the power circuit, and at the same time eliminating the signal conversion process brought by optocoupler feedback, with high timeliness. In some embodiments, the isolation module includes a wireless communication module or an optical communication module. In some embodiments, the optical communication module includes an infrared transceiver module or a millimeter wave transceiver module. In some embodiments, the power circuit further includes a self-excited soft start circuit, which is connected to the receiving end of the isolation module and the switching tube of the primary circuit, and is used to perform switching control on the switching tube of the primary circuit to enable the power circuit to self-excite and soft start, and after the start is completed, control the receiving end of the isolation module to be connected to the switching tube of the primary circuit. In some embodiments, the self-excited soft start circuit includes: an oscillation circuit for generating a carrier signal; a comparison circuit connected to the oscillation circuit for comparing the carrier signal with a fundamental wave signal to generate a second switching control signal; a selection circuit connected to the comparison circuit, the receiving end of the isolation module, and the switching tube of the primary circuit, and is used to control the comparison circuit to be connected to the switching tube of the primary circuit during the self-excited soft start of the power circuit, so as to perform switching control on the switching tube of the primary circuit through the second switching control signal to enable the power circuit to soft start, and when the power circuit starts and is completed, control the receiving end of the isolation module to be connected to the switching tube of the primary circuit. In some embodiments, the self-excited soft start circuit further includes a first power supply circuit, which is connected to the primary circuit, the oscillation circuit, the comparison circuit, and the selection circuit, and is used to supply power to the oscillation circuit, the comparison circuit, and the selection circuit. In some embodiments, the first switching control signal and the second switching control signal are PWM control signals. In some embodiments, the power circuit further includes a second power supply circuit connected to the second secondary winding of the transformer, and the second power supply circuit is connected to the receiving end of the isolation module and is used to supply power to the receiving end of the isolation module; wherein, the secondary circuit is also connected to the transmitting end of the isolation module and is used to supply power to the transmitting end of the isolation module. In some embodiments, the control module includes: a sampling unit connected to the secondary circuit for sampling the output voltage of the secondary circuit; a control logic unit connected to the sampling unit for generating a first switching control signal based on the output voltage of the secondary circuit; a feedback unit connected to the control logic unit and the transmitting end of the isolation module for providing a first switching control signal adapted to the isolation module. In some embodiments, the control module further includes: a control circuit connected to the control logic unit and the switching tube of the secondary circuit, wherein the control logic unit is further used to generate a third switching control signal based on the output voltage of the secondary circuit, and the control circuit is used to perform switching control on the switching tube of the secondary circuit based on the third switching control signal. In some embodiments, the transformer, the primary circuit, and the secondary circuit constitute a flyback converter or a forward converter. To achieve the above object, an embodiment of the second aspect of the present invention provides a charging device, including the aforementioned power supply circuit. According to the charging device of the embodiment of the present invention, through the aforementioned power supply circuit, the first switch control signal is transmitted to the switching tube of the primary circuit through the isolation module to control the switching tube of the primary circuit, realizing direct control of the primary side from the secondary side, eliminating the PWM controller on the primary side, effectively reducing the volume of the power supply circuit, and at the same time eliminating the signal conversion process brought by optocoupler feedback, having high timeliness. Additional aspects and advantages of the present invention will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present invention. Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention. In the related art, fast charging of electronic devices is achieved through a flyback conversion circuit. In this circuit, an output voltage detection circuit is provided on the secondary side to detect the output voltage on the secondary side, and the detected voltage is transmitted to the PWM controller on the primary side through an optocoupler. The switching tube on the primary side is controlled by the PWM controller, thereby realizing the adjustment of the output voltage on the primary side to achieve the purpose of fast charging. Specifically, referring to FIG. 1, the output voltage on the secondary side is sampled by sampling resistors R1 and R2, the sampled voltage is stabilized by capacitor C, and the conduction or cutoff of the optocoupler is controlled by zener diode Z based on the sampled voltage, so as to transmit the output voltage on the secondary side to the PWM controller on the primary side through the optocoupler. The PWM controller generates a PWM control signal with a corresponding duty cycle based on the feedback voltage, and controls the switching tube Q1 on the primary side based on the PWM control signal to realize the adjustment of the output voltage on the primary side, and further realize the adjustment of the output voltage on the secondary side. In this circuit, the control of the primary side from the secondary side through the optocoupler feedback loop not only requires the use of more components, such as sampling resistors R1 and R2, capacitor C, zener diode Z, and PWM controller, resulting in a large volume of the power supply circuit, but also has poor control timeliness. Based on this, in an embodiment of the present invention, the first switch control signal is transmitted to the switch tube of the primary circuit through the isolation module to control the switch tube of the primary circuit, realizing direct control of the primary side from the secondary side, eliminating components such as the PWM controller and the voltage stabilizing diode Z on the primary side, effectively reducing the volume of the power supply circuit. At the same time, the signal conversion process brought by optocoupler feedback is eliminated, which has high timeliness. The power supply circuit and charging device proposed in the embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic structural diagram of a power supply circuit according to an embodiment of the present invention. Referring to FIG. 2, the power supply circuit may include: a transformer T, a primary circuit 11 connected to the primary winding of the transformer T, a secondary circuit 12 connected to the first secondary winding of the transformer T, an isolation module 13, and a control module 14. The control module 14 is connected to the secondary circuit 12 and the transmitting end of the isolation module 13, and the receiving end of the isolation module 13 is connected to the switch tube Q1 of the primary circuit 11. Among them, the control module 14 is configured to generate a first switch control signal based on the output voltage of the secondary circuit 12 and transmit it to the switch tube Q1 of the primary circuit 11 through the isolation module 13 to perform switch control on the switch tube Q1 of the primary circuit 11. Exemplarily, when the power supply circuit is working, the alternating current can be rectified into direct current by the primary circuit 11, then the direct current is inverted into alternating current, and after the transformer T steps up or steps down the alternating current, the secondary circuit 12 rectifies it to obtain the target direct current for use by the load. Among them, in order to make the voltage of the target direct current, that is, the output voltage of the secondary circuit 12, meet the preset requirements, the control module 14 can generate a first switch control signal, such as a PWM control signal, based on the output voltage of the secondary circuit 12, and send it from the transmitting end of the isolation module 13 to the receiving end of the isolation module 13, and then transmit it to the switch tube Q1 of the primary circuit 11 to perform switch control (i.e., on-off control) on the switch tube Q1 of the primary circuit 11 to adjust the output voltage of the primary circuit 11, and further adjust the output voltage of the secondary circuit 12. In this circuit, the first switch control signal is directly transmitted to the switching tube of the primary circuit through the isolation module to control the switching tube of the primary circuit, realizing direct control of the primary side by the secondary side. Components such as the PWM controller and the voltage stabilizing diode Z on the primary side are eliminated, effectively reducing the volume of the power supply circuit. At the same time, the signal conversion process brought by optocoupler feedback is eliminated (controlling the level on the secondary side, receiving the level on the primary side, adjusting the reference voltage of the PWM based on the received level, and then changing the duty cycle of the PWM control signal to control the switching tube on the primary side). For example, the first switch control signal on the secondary side can be quickly fed back to the primary side, having high timeliness and safety (fewer components, higher reliability and safety), and the switching frequency of the transmitted switch control signal is higher than that generated by the PWM controller (there is no need to modulate the signal to a high frequency, and the highest frequency of the switching tube of the primary circuit can be directly used); in addition, since the transmitted signal is the switch control signal, the response speed of the entire power supply circuit is fast, which is beneficial to reducing the volume of the transformer and the inductor (for circuits containing inductors), and can effectively reduce the output ripple and improve the output efficiency; in addition, this method can achieve better synchronous rectification. In some embodiments, the isolation module 13 includes a wireless communication module or an optical communication module. Among them, the optical communication module may include an infrared transceiver module, a millimeter wave transceiver module, etc. That is to say, the isolation module 13 can be a wireless communication module or an optical communication module. When it is a wireless communication module, the isolated transmission of the first switch control signal can be realized through wireless signals, thereby realizing the direct control of the switching tube on the primary side by the secondary side; when it is an optical communication module, it can specifically be infrared light or millimeter wave to realize the isolated transmission of the first switch control signal through infrared light or millimeter wave, etc., thereby realizing the direct control of the switching tube on the primary side by the secondary side. Compared with the optocoupler feedback method, this method can transmit data faster and more, thereby effectively reducing the volume of the power supply circuit and improving timeliness. In some embodiments, referring to FIG. 3, the power supply circuit further includes a self-excited soft start circuit 15. The self-excited soft start circuit 15 is connected to the receiving end of the isolation module 13 and the switching tube Q1 of the primary circuit 11, and is used to perform switch control on the switching tube Q1 of the primary circuit 11 to make the power supply circuit start self-excitedly and softly, and after the start is completed, control the receiving end of the isolation module 13 to be connected to the switching tube Q1 of the primary circuit 11. It should be noted that the self-excited soft start of the power supply circuit refers to a start mode in which the output voltage of the power supply circuit gradually increases from zero without the action of a control signal. Exemplarily, referring to FIG. 3, after the power supply circuit is powered on, the self-excited soft start circuit 15 starts to work. At this time, the receiving end of the isolation module 13 and the switching tube Q1 of the primary circuit 11 are in a disconnected state, that is, the switching tube Q1 of the primary circuit 11 does not receive the first switching control signal from the control module 14. At the same time, the self-excited soft start circuit 15 generates a control signal without the action of a control signal and controls the switching tube Q1 of the primary circuit 11 to gradually increase the output voltage of the secondary circuit 12. When the output voltage of the secondary circuit 12 reaches the preset value, the self-excited soft start circuit 15 controls the receiving end of the isolation module 13 to be connected to the switching tube Q1 of the primary circuit 11 to receive the first switching control signal from the control module 14 to control the switching tube on the primary side through the secondary side. In this way, the self-excited soft start of the power supply circuit is realized. In some embodiments, referring to FIG. 4, the self-excited soft start circuit 15 includes: an oscillation circuit 151, a comparison circuit 152, and a selection circuit 153. Among them, the oscillation circuit 151 is used to generate a carrier signal; the comparison circuit 152 is connected to the oscillation circuit 151 and is used to compare the carrier signal with the fundamental wave signal to generate a second switching control signal; the selection circuit 153 is connected to the comparison circuit 152, the receiving end of the isolation module 13, and the switching tube Q1 of the primary circuit 11, and is used to control the comparison circuit 152 to be connected to the switching tube Q1 of the primary circuit 11 during the self-excited soft start of the power supply circuit to perform switching control on the switching tube Q1 of the primary circuit 11 through the second switching control signal to enable the self-excited soft start of the power supply circuit, and to control the receiving end of the isolation module 13 to be connected to the switching tube Q1 of the primary circuit 11 when the power supply circuit starts up. Specifically, the oscillation circuit 151 can be an RC oscillation circuit, and a carrier signal is generated through the RC oscillation circuit. For example, the carrier signal can be a triangular wave signal. The comparison circuit 152 can be a comparator. The first input end of the comparator is connected to the oscillation circuit 151, and the second input end of the comparator is connected to the reference signal terminal. The reference signal terminal is used to provide a fundamental wave signal. If the fundamental wave signal is a fixed-level signal, the comparator compares the carrier signal and the fundamental wave signal to generate a second switching control signal. For example, the amplitude of the triangular wave signal and the fixed-level signal is compared to generate a second switching control signal, such as a PWM control signal. The selection circuit 153 may include an RC delay circuit and a controllable switch. When the delay time determined by RC (i.e., resistance and capacitance) is not reached, the RC delay circuit outputs a first control signal to control the controllable switch to connect the comparison circuit 152 to the switch tube Q1 of the primary circuit 11, so as to perform switch control on the switch tube Q1 of the primary circuit 11 through the second switch control signal, realizing the self-excited soft start of the power supply circuit. When the self-excited soft start of the power supply circuit is completed, that is, when the delay time determined by RC is reached, the RC delay circuit outputs a second control signal to control the controllable switch to connect the receiving end of the isolation module 13 to the switch tube Q1 of the primary circuit 11, so as to perform switch control on the switch tube Q1 of the primary circuit 11 through the first switch control signal sent by the control module 14. In this way, the self-excited soft start of the power supply circuit is realized. It should be noted that based on the fact that the isolation module 13 can transmit data faster and more, the control module 14 can also transmit the output voltage of the secondary circuit 12 to the self-excited soft start circuit 15 through the isolation module 13. The selection circuit 153 in the self-excited soft start circuit 15 determines whether to jump out of the soft start and the control module 14 takes over the control of the switch tube Q1 of the primary circuit 11 to adjust the output voltage. In some embodiments, referring to FIG. 4, the self-excited soft start circuit 15 further includes a first power supply circuit 154. The first power supply circuit 154 is connected to the primary circuit 11, the oscillation circuit 151, the comparison circuit 152, and the selection circuit 153, and is used to supply power to the oscillation circuit 151, the comparison circuit 152, and the selection circuit 153. Exemplarily, the first power supply circuit 154 may be a charge pump, which is used to boost the DC power of the primary circuit 11 to obtain the required DC power to supply power to the self-excited soft start circuit 15. In some embodiments, referring to FIG. 5, the power supply circuit further includes a second power supply circuit 16 connected to the second secondary winding of the transformer T. The second power supply circuit 16 is connected to the receiving end of the isolation module 13 and is used to supply power to the receiving end of the isolation module 13; wherein, the secondary circuit 12 is further connected to the transmitting end of the isolation module 13 and is used to supply power to the transmitting end of the isolation module 13. Specifically, power needs to be supplied to the isolation module 13 to make it work. When power is supplied, the receiving end of the isolation module 13 can be powered through the second power supply circuit 16, and the transmitting end of the isolation module 13 can be powered through the secondary circuit 12, so as to realize independent isolated power supply for the transmitting end and the receiving end, and improve the safety of the isolation module 13. Exemplarily, the second power supply circuit 16 can be a rectifying circuit to convert the alternating current of the transformer T into direct current to supply power to the receiving end of the isolation module 13. Since the secondary circuit 12 connected to the transformer T is used to convert alternating current into direct current, the direct current can be directly provided to the transmitting end of the isolation module 13. It can be understood that if the converted direct current does not match the voltage required by the transmitting end of the isolation module 13, corresponding buck-boost circuits or the like can be added, or a third power supply circuit can be added, and specific details are not limited here. In some embodiments, referring to FIG. 6, the control module 14 includes: a sampling unit 141, a control logic unit 142, and a feedback unit 143. Among them, the sampling unit 141 is connected to the secondary circuit 12 and is used to sample the output voltage of the secondary circuit 12; the control logic unit 142 is connected to the sampling unit 141 and is used to generate a first switch control signal based on the output voltage of the secondary circuit 12; the feedback unit 143 is connected to the control logic unit 142 and the transmitting end of the isolation module 13 and is used to provide a first switch control signal adapted to the isolation module 13. Specifically, the sampling unit 141 can be an ADC analog-to-digital conversion unit, which is used to sample the output voltage, output current, etc. of the secondary circuit 12 and provide them to the control logic unit 142. As the control core of the power supply circuit, the control logic unit 142 realizes the control of the entire power supply circuit, including but not limited to generating a first switch control signal based on the output voltage of the secondary circuit 12, judging whether the output power of the power supply circuit meets the expectation based on the output voltage and output current of the secondary circuit 12, and sampling various protocol signals. For example, when the power supply circuit is used for charging, the charging protocol signal is obtained. The feedback unit 143 is mainly used to provide wireless or optical communication corresponding to the first switch control signal required by the isolation module 13 to realize the direct control of the switch tube on the primary side, and further control the output voltage on the secondary side. It should be noted that the specific structure of the feedback unit 143 is not limited here. When the power supply circuit is powered on, the sampling unit 141 immediately detects the output voltage of the secondary circuit 12, and the control logic unit 142 generates a first switch control signal based on the output voltage of the secondary circuit 12 and provides it to the isolation module 13 through the feedback unit 143, and is transmitted by the isolation module 13 to the switch tube Q1 of the primary circuit 11 to perform switch control on the switch tube Q1 of the primary circuit 11. In some embodiments, referring to FIG. 6, the control module 14 further includes a control circuit 144. The control circuit 144 is connected to the control logic unit 142 and the switching transistor Q2 of the secondary circuit 12. Among them, the control logic unit 142 is further configured to generate a third switching control signal based on the output voltage of the secondary circuit 12, and the control circuit 144 is configured to perform switching control on the switching transistor Q2 of the secondary circuit 12 based on the third switching control signal. Specifically, the control circuit 144 can be a PFC control circuit. With the sampling unit 141, it can achieve the switching control of the switching transistor Q2 of the secondary circuit 12, so that the output switching phase is consistent with the phase of the load fluctuation, thereby improving the efficiency of the entire output. Exemplarily, when the power supply circuit is powered on, the sampling unit 141 immediately detects the output voltage of the secondary circuit 12. The control logic unit 142 generates a third switching control signal, such as a PWM control signal, based on the output voltage of the secondary circuit 12, and sends it to the control circuit 144. The control circuit 144 performs drive control on the switching transistor Q2 of the secondary circuit 12 based on the third switching control signal to achieve power factor correction, thereby effectively improving the output efficiency of the power supply circuit. It should be noted that in the embodiments of the present invention, the specific circuit structures of the primary circuit 11 and the secondary circuit 12 are not limited. Exemplarily, the primary circuit 11, the transformer T, and the secondary circuit 12 can form a flyback converter, a forward converter, or a push-pull converter, etc. Exemplarily, referring to FIG. 7, the primary circuit 11 includes a rectifier bridge U1 and a switching transistor Q1. The input end of the rectifier bridge U1 is connected to the AC power supply AC. The first output end of the rectifier bridge U1 is connected to one end of the primary winding of the transformer T. The other end of the primary winding of the transformer T is connected to the first end of the switching transistor Q1. The second end of the switching transistor Q1 is connected to the second output end of the rectifier bridge U1. The secondary circuit 12 includes a switching transistor Q2 and a capacitor C1. One end of the first secondary winding of the transformer T is connected to the first voltage output end of the power supply circuit. The other end of the first secondary winding of the transformer T is connected to the first end of the switching transistor Q2. The second end of the switching transistor Q2 is connected to the second voltage output end of the power supply circuit. In this example, the second voltage output end of the power supply circuit is grounded; the capacitor C1 is connected in parallel between the first voltage output end and the second voltage output end of the power supply circuit. The specific descriptions of the isolation module 13, the control module 14, and the self-excited soft start circuit 15 can be referred to the foregoing, and will not be repeated here. The first power supply circuit 16 may include a diode D1 and a capacitor C2. Wherein, the anode of the diode D1 is connected to one end of the second secondary winding of the transformer T, the cathode of the diode D1 is connected to the receiving end of the isolation module 13, and the other end of the second secondary winding of the transformer T is connected to the second output end of the rectifier bridge U1; the capacitor C2 is connected between the cathode of the diode D1 and the other end of the second secondary winding of the transformer T. The emitting end of the isolation module 13 is also connected to the secondary circuit 12. After the power supply circuit is powered on, the rectifier bridge U1 converts the alternating current provided by the AC power supply AC into quasi-direct current, and performs periodic switching control on the switching tube Q1 through the self-excited soft start circuit 15, so as to boost or buck the quasi-direct current through the transformer T and then convert it into direct current output through the secondary circuit 12. When the output voltage of the secondary circuit 12 reaches the preset value, the self-excited soft start circuit 15 controls the receiving end of the isolation module 13 to be connected to the switching tube Q1. At this time, the control module 14 performs periodic switching control on the switching tube Q1 to adjust the output voltage of the secondary circuit 12. During this process, the control module 14 also performs switching control on the switching tube Q1 of the secondary circuit 12 to achieve rectification and power factor correction. It can be seen from the comparison between FIG. 7 and FIG. 1 that the power supply circuit of the embodiment of the present invention omits the voltage stabilizing diode Z, the capacitors C, the sampling resistors R1 and R2, the power correction chip, and the PWM controller, and the secondary side can communicate with the primary side more efficiently and quickly. It should be noted that the power supply circuit of the embodiment of the present invention can be used to charge an electronic device. Taking the power supply circuit shown in FIG. 7 as an example, when it is used to charge an electronic device, the power supply circuit may further include a charging interface. Exemplarily, referring to FIG. 8, the power supply circuit may include a USB port, and charging of an electronic device is realized through the USB port, which is applicable to a single-port fast charging application scenario. Exemplarily, referring to FIG. 9, the power supply circuit may include multiple USB ports, and charging of multiple electronic devices is realized through the multiple USB ports. It can be understood that when the power supply circuit includes multiple USB ports, one of the USB ports can be directly connected to the output end of the secondary circuit 12, thereby omitting a buck or boost circuit and reducing charging loss. Other USB ports can be correspondingly provided with buck or boost circuits to convert the output voltage of the secondary circuit 12 through the buck or boost circuit to meet the actual needs, which is applicable to two-port or more-port fast charging application scenarios that require independent primary buck. During charging, the control module 14 can control the switching tube Q1 to adjust the output voltage of the primary circuit 11, and further adjust the charging voltage of the USB port connected to the output end of the secondary circuit 12. For other USB ports, the corresponding buck or boost circuit can be controlled by the control module 14 to meet the corresponding charging requirements. This method omits the primary boost or buck and can improve the output efficiency of the power supply circuit. In addition, when the power circuit includes multiple USB ports, a protocol conversion unit can be set in the control module 14 to implement the charging protocol conversion for multiple USB ports and send it to the control logic unit 142 in the control module 14, so as to implement the acquisition of the charging protocol through the control logic unit 142, and control the switching tubes Q1 and Q2 and the boost or buck circuit corresponding to the USB port based on the acquired charging protocol, so that the output voltage meets the charging requirements. Among them, the protocol conversion unit is used to detect the type of charging protocol that can be supported and the maximum charging power that can be supported after the electronic device is inserted. For example, the charging protocols include but are not limited to PD2.0 / 3.0 / 3.1, BC1.2, QC / 2.0 / 3.0 / 4.0 / 5.0, Apple fast charging protocol, MTK fast charging protocol, Huawei FCP / SCP / SSCP, fusion fast charging protocol, and Samsung fast charging protocol, etc. Thus, compared with the power circuit shown in FIG. 10, by setting a protocol conversion unit and a boost or buck circuit for each USB port, the volume of the power circuit is effectively reduced, the yield of the product is improved, and the production cost is reduced. In summary, for the power circuit according to the embodiment of the present invention, the first switch control signal is transmitted to the switching tube of the primary circuit through the isolation module to control the switching tube of the primary circuit, realizing direct control of the primary side by the secondary side, eliminating the PWM controller on the primary side, effectively reducing the volume of the power circuit, and at the same time eliminating the signal conversion process brought by optocoupler feedback, having high timeliness. In some embodiments, a charging device is also proposed, including the aforementioned power circuit. It should be noted that the charging device includes but is not limited to adapters, socket strips, energy storage systems, etc. For the charging device according to the embodiment of the present invention, through the aforementioned power circuit, the first switch control signal is transmitted to the switching tube of the primary circuit through the isolation module to control the switching tube of the primary circuit, realizing direct control of the primary side by the secondary side, eliminating the PWM controller on the primary side, effectively reducing the volume of the power circuit, and at the same time eliminating the signal conversion process brought by optocoupler feedback, having high timeliness. It should be understood that each part of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: discrete logic circuits with logic gate circuits for implementing logical functions for data signals, application-specific integrated circuits with suitable combinational logic gate circuits, programmable logic gate arrays (PGAs), field-programmable logic gate arrays (FPGAs), etc. In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined. In the present invention, unless otherwise clearly specified and defined, terms such as "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention. 11: Primary circuit 12: Secondary circuit 13: Isolation module 14: Control module 141: Sampling unit 142: Control logic unit 143: Feedback unit 144: Control circuit 15: Self-excited soft start circuit 151: Oscillation circuit 152: Comparison circuit 153: Selection circuit 154: First power supply circuit 16: Second power supply circuit C: Capacitor C1: Capacitor C2: Capacitor D1: Diode R1: Sampling resistor R2: Sampling resistor Q1: Switching tube Q2: Switching tube T: Transformer U1: Rectifier bridge Z: Zener diode AC: AC power supply Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, where: FIG. 1 is a schematic structural diagram of a power circuit in the related art; FIG. 2 is a schematic structural diagram of a power circuit according to the first embodiment of the present invention; FIG. 3 is a schematic structural diagram of a power circuit according to the second embodiment of the present invention; FIG. 4 is a schematic structural diagram of a power circuit according to the third embodiment of the present invention; FIG. 5 is a schematic structural diagram of a power circuit according to the fourth embodiment of the present invention; FIG. 6 is a schematic structural diagram of a power circuit according to the fifth embodiment of the present invention; FIG. 7 is a schematic structural diagram of a power circuit according to the sixth embodiment of the present invention; FIG. 8 is a schematic structural diagram of a power circuit according to the seventh embodiment of the present invention; FIG. 9 is a schematic structural diagram of a power circuit according to the eighth embodiment of the present invention; and FIG. 10 is a schematic structural diagram of another power circuit in the related art. 11: primary circuit 12: secondary circuit 13: isolation module 14: control module

Claims

1. A power supply circuit, wherein, include: The system comprises a transformer, a primary circuit connected to the primary winding of the transformer, a secondary circuit connected to the first and second windings of the transformer, an isolation module, and a control module. The control module is connected to the transmitting end of the secondary circuit and the isolation module, and the receiving end of the isolation module is connected to the switching transistor of the primary circuit. The control module generates a first switching control signal based on the output voltage of the secondary circuit and transmits it to the switching transistor of the primary circuit through the isolation module to control the switching of the primary circuit. The isolation module includes a wireless communication module or an optical communication module. When the isolation module is a wireless communication module, the first switching control signal is transmitted in isolation via a wireless signal, thereby directly controlling the switching transistor of the primary circuit. When the isolation module is an optical communication module, the first switching control signal is transmitted in isolation via infrared light or millimeter waves, thereby directly controlling the switching transistor of the primary circuit. The power supply circuit further includes a second power supply circuit connected to the second secondary winding of the transformer. The second power supply circuit is connected to the receiving end of the isolation module and is used to supply power to the receiving end of the isolation module. The secondary circuit is also connected to the transmitting end of the isolation module and is used to supply power to the transmitting end of the isolation module.

2. The power supply circuit according to claim 1, wherein, The optical communication module includes an infrared transceiver module or a millimeter-wave transceiver module.

3. The power supply circuit according to claim 1, wherein, It also includes a self-excited soft-start circuit, which is connected to the receiving end of the isolation module and the switching transistor of the primary circuit. The self-excited soft-start circuit is used to control the switching transistor of the primary circuit to enable the power supply circuit to self-excite soft-start, and after the startup is completed, controls the receiving end of the isolation module to connect to the switching transistor of the primary circuit.

4. The power supply circuit according to claim 3, wherein, The self-excited soft-start circuit includes: an oscillation circuit for generating a carrier signal; a comparator circuit connected to the oscillation circuit for comparing the carrier signal with a fundamental signal to generate a second switch control signal; and a selection circuit connected to the comparator circuit, the receiving end of the isolation module, and the switching transistor of the primary circuit. During the self-excited soft-start of the power circuit, the selection circuit controls the connection between the comparator circuit and the switching transistor of the primary circuit to control the switching of the primary circuit via the second switch control signal, thereby enabling the soft start of the power circuit. Upon completion of the power circuit startup, the selection circuit controls the connection between the receiving end of the isolation module and the switching transistor of the primary circuit.

5. The power supply circuit according to claim 4, wherein, The self-excited soft-start circuit further includes a first power supply circuit, which is connected to the primary circuit, the oscillation circuit, the comparator circuit, and the selection circuit, and is used to supply power to the oscillation circuit, the comparator circuit, and the selection circuit.

6. The power supply circuit according to claim 1, wherein, The control module includes: a sampling unit connected to the secondary circuit for sampling the output voltage of the secondary circuit; a control logic unit connected to the sampling unit for generating a first switch control signal based on the output voltage of the secondary circuit; and a feedback unit connected to the control logic unit and the transmitter of the isolation module for providing a first switch control signal adapted to the isolation module.

7. The power supply circuit according to claim 6, wherein, The control module further includes a control circuit, which is connected to the control logic unit and the switching transistor of the secondary circuit. The control logic unit is further configured to generate a third switching control signal based on the output voltage of the secondary circuit, and the control circuit is configured to control the switching transistor of the secondary circuit based on the third switching control signal.

8. A charging device, wherein, Includes the power supply circuit described in any one of claims 1-7.

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