Power supply system for switching power supply

Abstract

The invention relates to the technical field of switching power supplies, in particular to a power supply system for a switching power supply, which is characterized in that the output end of a main loop is electrically connected with an external voltage conversion module and an external detection access module in sequence and then is externally connected with an external sensor; the external voltage conversion module is also externally connected with other external devices and is also externally connected with a light modulator or a light modulation bus after being electrically connected with the light modulation power supply module; the external voltage conversion module is used for isolating and supplying power after voltage conversion; the dimming power supply module is also electrically connected with the microcontroller, and the microcontroller controls power supply to the dimmer or the dimming bus; the output end of the main loop is further electrically connected with an internal voltage conversion module, then is electrically connected with an SGND ground end connecting circuit and a GND ground end connecting circuit of the main loop, and is isolated by the internal voltage conversion module and supplied with power through voltage conversion; the problem that an existing switching power supply cannot give consideration to internal and external power supply to reduce the power supply complexity of an intelligent lighting system is solved.

Description

Technical Field

[0001] The invention relates to the technical field of switching power supplies, in particular to a power supply system for a switching power supply. Background Art

[0002] In actual applications, switching power supplies, dimmers and smart lamps are usually integrated into a smart lighting system. Users can remotely control the switch, brightness, color temperature and other parameters of the lights through smart devices such as mobile phone apps and smart speakers. These smart devices transmit data and interact with the smart lighting system through communication systems (such as Wi-Fi, Bluetooth, etc.). After the control system receives the user's instructions, it will send instructions to the dimmer according to the preset program and control strategy. After receiving the instructions, the dimmer changes the output current or voltage by adjusting its internal circuit, thereby achieving precise adjustment of the brightness of the lamp.

[0003] However, with the advancement of technology and the development of electronic equipment, the performance and functional requirements of the switching power supply of the intelligent lighting system are also constantly increasing. The switching power supply needs to take into account the external environment to adjust the working state. For example, multiple functional circuits such as external fault warning and external environment monitoring are required for external perception. Each functional circuit has its own power supply circuit, sensor, sensor signal recognition circuit and signal feedback circuit, etc. This results in a large number of peripheral circuits of the switching power supply, and the circuit structure and power supply network of the overall switching power supply are complex.

[0004] More importantly, although the dimmers controlled by the switching power supply belong to the same intelligent lighting system, the dimmers have their own power supply circuits and need to occupy a power interface. When there are a large number of dimmers, the power interfaces occupied will be very large and involve complex dimmer power line layout, making the construction of the entire intelligent lighting system complex and difficult to operate and maintain. Summary of the invention

[0005] In view of the above-mentioned defects, the purpose of the present invention is to propose a power supply system for a switching power supply, which solves the problem that the existing switching power supply cannot take into account both internal and external power supply to reduce the power supply complexity of the intelligent lighting system.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A power supply system for a switching power supply, comprising a main circuit and a microcontroller, and also comprising an external voltage conversion module, an external detection access module, an internal voltage conversion module and a dimming power supply module; the output end of the main circuit is electrically connected to the external voltage conversion module and the external detection access module in sequence, the external detection access module is externally connected to an external sensor; the external voltage conversion module is also externally connected to other external devices; the external voltage conversion module is also electrically connected to the dimming power supply module, and the dimming power supply module is externally connected to a dimmer or a dimming bus;

[0008] The external voltage conversion module is used for isolation, and is also used for converting the output voltage of the main circuit to power the other external devices and the dimming power supply module, and for powering the external sensor through the external detection access module;

[0009] The dimming power supply module is also electrically connected to the microcontroller, and the microcontroller controls the dimming power supply module to supply power to the dimmer or the dimming bus;

[0010] The output end of the main circuit is also electrically connected to the input end of the internal voltage conversion module, and the first output end and the second output end of the internal voltage conversion module are electrically connected to the SGND ground terminal circuit and the GND ground terminal circuit of the main circuit respectively;

[0011] The internal voltage conversion module is used for isolation and is also used for performing voltage conversion on the output voltage of the main circuit to generate a first conversion voltage and a second conversion voltage, wherein the first conversion voltage and the second conversion voltage respectively power the SGND ground terminal circuit and the GND ground terminal circuit of the main circuit.

[0012] Further, the external voltage conversion module includes a capacitor C49, a transformer T3, a flyback power supply processing circuit, a flyback feedback circuit, a first output processing circuit and a second output processing circuit; after the capacitor C49 is connected in parallel between the output end of the main loop 1 and the GND ground end, it is electrically connected to the primary side of the transformer T3; the secondary side A of the transformer T3 is electrically connected to the other external devices via the first output processing circuit, and the flyback feedback circuit is electrically connected between the primary side of the transformer T3 and the first output processing circuit; the first output processing circuit is also electrically connected to the dimming power supply module;

[0013] The secondary side C of the transformer T3 is electrically connected to the flyback feedback circuit via the flyback power supply processing circuit;

[0014] The secondary side B of the transformer T3 is electrically connected to the external detection access module via the second output processing circuit.

[0015] Further, the dimming power supply module includes a resistor R101, a photocoupler U18, a resistor R103, a resistor R106, a resistor R107, a resistor R115, a resistor R109, a resistor R103, a resistor R116, a resistor R104, a resistor R123, a diode D22, a MOS tube Q5, a controllable voltage source U19, a diode D21, a diode D23, a diode D24, a voltage regulator diode DZ3, a capacitor C60, a transistor Q6 and a transistor Q7; one end of the resistor R101 is electrically connected to the microcontroller, the drain of the MOS tube Q5 is electrically connected to the external voltage conversion module, and the cathode of the diode D21 and the cathode of the diode D24 are both electrically connected to the dimmer or the dimming bus;

[0016] The other end of the resistor R101 is electrically connected to the anode of the light source of the photoelectric coupler U18, the cathode of the light source of the photoelectric coupler U18 is connected to the GND ground terminal, the light receiver collector of the photoelectric coupler U18 is electrically connected to one end of the resistor R103, the other end of the resistor R103, one end of the resistor R106, and one end of the resistor R107 are all electrically connected to the cathode of the diode D22, the other end of the resistor R106 and the other end of the resistor R107 are all electrically connected to the drain of the MOS tube Q5, the anode of the diode D22, the anode of the diode D23, one end of the resistor R109, the anode of the controllable voltage regulator U19, one end of the resistor R116, one end of the capacitor C60, the emitter of the transistor Q6, the base of the transistor Q7, and one end of the resistor R123 are all electrically connected to the anode of the diode D21. The cathode of the diode D23, the base of the transistor Q6, and the other end of the capacitor C60 are all electrically connected to one end of the resistor R104, the other end of the resistor R104 is electrically connected to the cathode of the diode D24, the anode of the diode D24 is electrically connected to the anode of the voltage-stabilizing diode DZ3, the cathode of the voltage-stabilizing diode DZ3 and the other end of the resistor R123 are all electrically connected to the emitter of the transistor Q7, the collector of the transistor Q7, the collector of the transistor Q6, the other end of the resistor R116, the cathode of the controllable voltage-stabilizing source U19, and the gate of the MOS tube Q5 are all electrically connected to the emitter of the light receiver of the photocoupler U18, the other end of the resistor R109 and the source of the MOS tube Q5 are all electrically connected to one end of the resistor R115, and the other end of the resistor R115 is electrically connected to the reference electrode of the controllable voltage-stabilizing source U19.

[0017] Further, the internal voltage conversion module includes a voltage stabilizing chip U10, an AC / DC constant voltage chip U11, a capacitor C38, a capacitor CE1, a capacitor C40, a capacitor CE2, a capacitor C44, a capacitor CE4, a capacitor C39, a capacitor C36, a capacitor C41, a resistor R77, a diode D14, a transformer T2, a resistor R86, a resistor R87, a diode D15, a diode D16 and a voltage stabilizing diode DZ2; the power tube drain terminal of the AC / DC constant voltage chip U11 is used as the input terminal of the internal voltage conversion module, the output terminal of the voltage stabilizing chip U10 is used as the first output terminal of the internal voltage conversion module, and the opposite-name terminal of the primary side of the transformer T2 is used as the second output terminal of the internal voltage conversion module;

[0018] One end of the capacitor C36 and one end of the capacitor C41 are electrically connected to the drain end of the power tube of the AC / DC constant voltage chip U11, the other end of the capacitor C41 is connected to the GND ground end, the other end of the capacitor C36, the anode of the diode D15, the positive electrode of the capacitor CE4, one end of the capacitor C44, and one end of the resistor R86 are electrically connected to the opposite end of the primary side of the transformer T2, the cathode of the diode D15 is electrically connected to the cathode of the voltage regulator diode DZ2, one end of the capacitor C39, the VCC end of the AC / DC constant voltage chip U11, and the positive electrode of the capacitor C41 are electrically connected to the VCC end of the AC / DC constant voltage chip U11. The voltage selection end of the C / DC constant voltage chip U11 is electrically connected to the anode of the voltage zener diode DZ2, the GND end of the AC / DC constant voltage chip U11, the other end of the capacitor C39, and the cathode of the diode D16 are electrically connected to the same-name end of the primary side of the transformer T2, the current sampling end of the AC / DC constant voltage chip U11 is electrically connected to the GND end of the AC / DC constant voltage chip U11 via the resistor R87, and the anode of the diode D16, the cathode of the capacitor CE4, the other end of the capacitor C44, and the other end of the resistor R86 are all connected to the GND ground end;

[0019] The same-name terminal of the secondary side of the transformer T2 is electrically connected to the anode of the diode D14, the cathode of the diode D14 is electrically connected to the input terminal of the voltage stabilizing chip U10 via the resistor R77, the GND terminal of the voltage stabilizing chip U10 is connected to the SGND ground terminal, the capacitor C40 and the capacitor CE2 are connected in parallel between the input terminal of the voltage stabilizing chip U10 and the SGND ground terminal, and the capacitor C38 and the capacitor CE1 are connected in parallel between the output terminal of the voltage stabilizing chip U10 and the SGND ground terminal.

[0020] Furthermore, it also includes an external detection feedback module; the external detection access module is electrically connected to the microcontroller via the external detection feedback module;

[0021] The external detection access module is also used to receive different types of detection signals from the external sensor, generate the same type of feedback signal, and transmit the feedback signal to the microcontroller through the external detection feedback module.

[0022] Furthermore, the external detection access module includes a plurality of signal conversion chips U15 and a signal preprocessing circuit; the VCC terminal and the VIN terminal of the plurality of signal conversion chip U15 are electrically connected to the external voltage conversion module, the external sensor is electrically connected to the input terminal of the plurality of signal conversion chip U15 via the signal preprocessing circuit, and the output terminal of the plurality of signal conversion chip U15 is electrically connected to the microcontroller via the external detection feedback module;

[0023] The multiple signal conversion chip U15 is used to receive different types of detection signals from the external sensor through the signal preprocessing circuit, generate the same type of feedback signals, and transmit the feedback signals to the microcontroller through the external detection feedback module.

[0024] Further, the external detection feedback module includes a resistor R121, a capacitor C64, a resistor R125, a photoelectric coupler U21, a resistor R126, a capacitor C65 and a resistor R124; the anode of the light source of the photoelectric coupler U21 is electrically connected to the external detection access module via the resistor R121, the cathode of the light source of the photoelectric coupler U21 is connected to the SGND ground terminal, and the resistor R125 and the capacitor C64 are connected in parallel between the anode and the cathode of the light source of the photoelectric coupler U21;

[0025] The collector of the photoelectric coupler U21 light receiver is connected to a 3V3 power supply, the emitter of the photoelectric coupler U21 light receiver is electrically connected to the microcontroller via the resistor R124, the emitter of the photoelectric coupler U21 light receiver is connected to the GND ground terminal, and the resistor R126 and the capacitor C65 are connected in parallel between the emitter of the photoelectric coupler U21 light receiver and the GND ground terminal.

[0026] Furthermore, the preprocessing circuit includes capacitor C55, capacitor C56, resistor R108, bidirectional TVS diode TVS1, inductor L9 and inductor L10; one end of the resistor R108 is electrically connected to the input end of the multiple signal conversion chip U15, one end of the resistor R108 is also electrically connected to one end of the capacitor C56, the other end of the resistor R108 and one end of the bidirectional TVS diode TVS1 are both electrically connected to one end of the inductor L9, the other end of the inductor L9 is electrically connected to one end of the capacitor C55, the other end of the capacitor C56, the other end of the bidirectional TVS diode TVS1 and one end of the inductor L10 are all connected to the SGND ground terminal, the other end of the inductor L10 is electrically connected to the other end of the capacitor C55, and one end and the other end of the capacitor C55 are both electrically connected to the external sensor.

[0027] Furthermore, it also includes a switch module; the second output end of the internal voltage conversion module is also electrically connected to the input end of the switch module, the output end of the switch module is electrically connected to the flyback drive module and the PFC module of the main circuit respectively, and the control end of the switch module is electrically connected to the microcontroller;

[0028] The microcontroller controls the second conversion voltage to supply power to the flyback drive module and the PFC module of the main loop through the switch module.

[0029] Further, the switch module includes a resistor R78, a resistor R80, a resistor R76, a resistor R45, a capacitor C37, a transistor Q7 and a MOS transistor Q4; one end of the resistor R78 is used as a control end of the switch module, the drain of the MOS transistor Q4 is used as an input end of the switch module, and the source of the MOS transistor Q4 is used as an output end of the switch module;

[0030] The other end of the resistor R78 is electrically connected to the base of the transistor Q7, the collector of the transistor Q7 is electrically connected to the gate of the MOS transistor Q4, the emitter of the transistor Q7 is connected to the GND ground terminal, the resistor R80 and the capacitor C37 are connected in parallel between the base of the transistor Q7 and the GND ground terminal, the resistor R76 is connected in parallel between the collector of the transistor Q7 and the GND ground terminal, and the resistor R45 is connected in parallel between the gate and the drain of the MOS transistor Q4.

[0031] The technical solution provided by the present invention may include the following beneficial effects: in order to enable the switching power supply to have the ability to supply power to the outside in addition to supplying power to the internal circuit, the power supply system of the switching power supply is carefully planned and managed so that it can provide segmented power supply according to the specific internal and external power supply conditions.

[0032] First, an external voltage conversion module and an internal voltage conversion module are respectively provided to perform voltage conversion to power the external circuit and the internal circuit respectively, and the isolation function of the external voltage conversion module and the internal voltage conversion module themselves is utilized to isolate the internal and external power supply lines to avoid mutual interference.

[0033] Then, the external power supply is divided into three parts: one is the power supply of external sensors. Since it is necessary to provide electrical energy while receiving signals, an external detection access module needs to be set up separately to power the external sensors; the second is the power supply of dimmers or dimming buses. Therefore, some power supplies consume a lot of energy and need to be controlled and selectively turned on, so a separate dimming power supply module is set up to control when to supply power by the microcontroller; the third is the power supply of other external devices. Taking into account that the intelligent lighting system is becoming more and more complex and will include more and more devices, in order to centrally manage the power supply, it may also need to be powered by a switching power supply. Therefore, the external voltage conversion module reserves an interface for external connection of other external devices for direct power supply; the external power supply uniformly plans and manages the external power supply of the switching power supply through these three power supply methods, which greatly reduces the complexity of the power supply circuit of the intelligent lighting system, reduces the occupancy of the power supply interface, and simplifies the line layout of the intelligent lighting system.

[0034] Finally, the internal voltage conversion module mainly provides power supply to circuits with different ground terminals in the internal circuit to avoid mutual interference; therefore, the internal voltage conversion module is set to convert the output voltage of the main circuit to generate a first conversion voltage (BL.V) and a second conversion voltage (V), which are used to supply power to the SGND ground terminal circuit and the GND ground terminal circuit of the main circuit respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The schematic diagram of a power supply system for a switching power supply according to one embodiment of the present invention.

[0036] Figure 2 Yes Figure 1 A partial circuit diagram of the external voltage conversion module is shown.

[0037] Figure 3 Yes Figure 1 The partial circuit diagram of the external voltage conversion module and the circuit diagrams of the external detection access module and the external detection feedback module are shown.

[0038] Figure 4 Yes Figure 1 The circuit diagram of the dimming power supply module is shown.

[0039] Figure 5 Yes Figure 1 The circuit diagram of the internal voltage conversion module is shown.

[0040] Figure 6 Yes Figure 1Circuit diagram of the switch module shown.

[0041] Wherein: main circuit 1, microcontroller 5, external voltage conversion module 2, external detection access module 3, internal voltage conversion module 6, dimming power supply module 8, capacitor C49, transformer T3, flyback power supply processing circuit 21, flyback feedback circuit 22, first output processing circuit 23, second output processing circuit 24, resistor R101, photocoupler U18, resistor R103, resistor R106, resistor R107, resistor R115, resistor R109, resistor R103, resistor R116, resistor R104, resistor R123, diode D22, MOS tube Q5, controllable voltage source U19, diode D21, diode D23, diode D24, voltage regulator diode DZ3, capacitor C60, transistor Q6, transistor Q7, voltage regulator chip U10, AC / DC constant voltage chip U11, capacitor C38, capacitor CE1, capacitor C40, capacitor CE2, capacitor C44, capacitor CE4, capacitor C39, capacitor C36, capacitor C41, resistor R77, diode D14, transformer T2, resistor R86, resistor R87, diode D15, diode D16, voltage regulator diode DZ2, external detection feedback module 4, multiple signal conversion chip U15, signal preprocessing circuit 31, resistor R121, capacitor C64, resistor R125, photocoupler U21, resistor R126, capacitor C65, resistor R124, capacitor C55, capacitor C56, resistor R108, bidirectional TVS diode TVS1, inductor L9, inductor L10, switch module 7, resistor R78, resistor R80, resistor R76, resistor R45, capacitor C37, transistor Q7, MOS tube Q4. DETAILED DESCRIPTION

[0042] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0043] In the description of the embodiments of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0044] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0045] Combine the following Figures 1 to 6 , describing a power supply system for a switching power supply according to an embodiment of the present invention.

[0046] A power supply system for a switching power supply, comprising a main circuit 1 and a microcontroller 5, and also comprising an external voltage conversion module 2, an external detection access module 3, an internal voltage conversion module 6 and a dimming power supply module 8; the output end of the main circuit 1 is electrically connected to the external voltage conversion module 2 and the external detection access module 3 in sequence, the external detection access module 3 is externally connected to an external sensor; the external voltage conversion module 2 is also externally connected to other external devices; the external voltage conversion module 2 is also electrically connected to the dimming power supply module 8, and the dimming power supply module 8 is externally connected to a dimmer or a dimming bus;

[0047] The external voltage conversion module 2 is used for isolation, and is also used to convert the output voltage of the main circuit 1 to supply power to other external devices and the dimming power supply module 8, and to supply power to external sensors through the external detection access module 3;

[0048] The dimming power supply module 8 is also electrically connected to the microcontroller 5, and the microcontroller 5 controls the dimming power supply module 8 to supply power to the dimmer or the dimming bus;

[0049] The output end of the main circuit 1 is also electrically connected to the input end of the internal voltage conversion module 6, and the first output end and the second output end of the internal voltage conversion module 6 are electrically connected to the SGND ground terminal circuit and the GND ground terminal circuit of the main circuit 1 respectively;

[0050] The internal voltage conversion module 6 is used for isolation and also for converting the output voltage of the main loop 1 to generate a first conversion voltage and a second conversion voltage, which respectively power the SGND ground terminal circuit and the GND ground terminal circuit of the main loop 1.

[0051] The present invention proposes a preferred embodiment of a power supply system for a switching power supply, such as Figure 1 As shown, in order to enable the switching power supply to have the ability to supply power to the external circuit in addition to supplying power to the internal circuit, the power supply system of the switching power supply is carefully planned and managed so that it can provide segmented power supply according to the specific internal and external power supply conditions.

[0052] First, an external voltage conversion module 2 and an internal voltage conversion module 6 are respectively provided to perform voltage conversion to power the external circuit and the internal circuit respectively, and the isolation function of the external voltage conversion module 2 and the internal voltage conversion module 6 is utilized to isolate the internal and external power supply lines to avoid mutual interference.

[0053] Then, the external power supply is divided into three parts: one is the power supply of external sensors. Since it is necessary to provide electrical energy while receiving signals, an external detection access module 3 needs to be separately set up to power the external sensors; the second is the power supply of dimmers or dimming buses. Therefore, some power supplies consume a lot of energy and need to be controlled and selectively turned on, so a separate dimming power supply module 8 is set up to control when to supply power by the microcontroller 5; the third is the power supply of other external devices. Considering that the intelligent lighting system is becoming more and more complex, more and more devices will be included. In order to centrally manage the power supply, it may also need to be powered by a switching power supply. Therefore, the external voltage conversion module 2 reserves an interface for externally connecting other external devices for direct power supply (if the voltage level does not match, the voltage can be further converted through this interface); the external power supply uniformly plans and manages the external power supply of the switching power supply through these three power supply methods, which greatly reduces the complexity of the power supply circuit of the intelligent lighting system, reduces the occupancy of the power supply interface, and simplifies the line layout of the intelligent lighting system.

[0054] Finally, the internal voltage conversion module 6 mainly provides power to circuits with different ground terminals in the internal circuit to avoid mutual interference; therefore, the internal voltage conversion module 6 performs voltage conversion on the output voltage of the main circuit 1 to generate a first conversion voltage (BL3.3V) and a second conversion voltage (18V), which are used to supply power to the SGND ground terminal circuit and the GND ground terminal circuit of the main circuit 1, respectively. It should be noted that further voltage conversion can be performed according to the power supply requirements of different circuits in the SGND ground terminal circuit and the GND ground terminal circuit (for example, in the GND ground terminal circuit, in addition to converting to 18V to power the flyback drive module and the PFC module, it is also necessary to power the microcontroller 5, so it is necessary to add a voltage stabilizing chip and its peripheral circuits to convert 18V into 3.3V to power the microcontroller 5).

[0055] Further, the external voltage conversion module 2 includes a capacitor C49, a transformer T3, a flyback power supply processing circuit 21, a flyback feedback circuit 22, a first output processing circuit 23 and a second output processing circuit 24; after the capacitor C49 is connected in parallel between the output end of the main loop 1 and the GND ground end, it is electrically connected to the primary side of the transformer T3; the secondary side A of the transformer T3 is electrically connected to other external devices through the first output processing circuit 23, and the flyback feedback circuit 22 is electrically connected between the primary side of the transformer T3 and the first output processing circuit 23; the first output processing circuit 23 is also electrically connected to the dimming power supply module 8;

[0056] The secondary side C of the transformer T3 is electrically connected to the flyback feedback circuit 22 via the flyback power supply processing circuit 21;

[0057] The secondary side B of the transformer T3 is electrically connected to the external detection access module 3 via the second output processing circuit 24 .

[0058] In this embodiment, Figure 2 and 3 As shown, the external voltage conversion module 2 mainly realizes three external power supply modes through the transformer T3; the output voltage of the main loop 1 is input into the primary side of the transformer T3 after being filtered by the capacitor C49, and the secondary side A of the transformer T3, the flyback feedback circuit 22 and the first output processing circuit 23 form a flyback power supply (the power supply is directly facing the outside, and the flyback type is preferably adopted to improve stability), which has high conversion efficiency and better stability, and can provide sufficient and stable electric energy for the secondary side of the transformer T3; and the power supply of the flyback feedback circuit 22 is converted from the secondary side C of the transformer T3 (ie, VDD), and the flyback power supply processing circuit 23 shapes and filters the power supply voltage, and the power supply voltage can also be adjusted through a voltage divider circuit composed of multiple resistors (such as resistor R96, resistor R128 and resistor R129).

[0059] Since the external detection access module 3 needs to be connected to the signal of the external sensor, it generally has its own receiving chip, which is actually powered by the secondary side B of the transformer T3, and the second output processing circuit 24 shapes and filters the power supply voltage.

[0060] It should be noted that the flyback feedback circuit 22 is mainly composed of a power supply chip U17 (such as OB2365x), an optocoupler U20 (isolation of different ground terminals), a controllable voltage regulator U22 and its peripheral circuits. The conduction amount of the controllable voltage regulator U22 is increased or decreased to determine when the optocoupler U20 is turned on and off. The power supply chip U17 adjusts the duty cycle through internal logic to balance the output voltage on the secondary side of the transformer T3. The flyback power supply processing circuit 21, the first output processing circuit 23 and the second output processing circuit 24 select diodes (to prevent reverse current), capacitors (filtering) and RCD absorption circuits (EMI) to form processing circuits to process the power supply voltage to ensure the quality of power, and are not limited here.

[0061] Further, the dimming power supply module 8 includes a resistor R101, a photocoupler U18, a resistor R103, a resistor R106, a resistor R107, a resistor R115, a resistor R109, a resistor R103, a resistor R116, a resistor R104, a resistor R123, a diode D22, a MOS tube Q5, a controllable voltage source U19, a diode D21, a diode D23, a diode D24, a voltage regulator diode DZ3, a capacitor C60, a transistor Q6 and a transistor Q7; one end of the resistor R101 is electrically connected to the microcontroller 5, the drain of the MOS tube Q5 is electrically connected to the external voltage conversion module 2, and the cathode of the diode D21 and the cathode of the diode D24 are both electrically connected to the dimmer or the dimming bus;

[0062] The other end of the resistor R101 is electrically connected to the anode of the light source of the photocoupler U18, the cathode of the light source of the photocoupler U18 is connected to the GND ground terminal, the light receiver collector of the photocoupler U18 is electrically connected to one end of the resistor R103, the other end of the resistor R103, one end of the resistor R106, and one end of the resistor R107 are all electrically connected to the cathode of the diode D22, the other end of the resistor R106 and the other end of the resistor R107 are all electrically connected to the drain of the MOS tube Q5, the anode of the diode D22, the anode of the diode D23, one end of the resistor R109, the anode of the controllable voltage source U19, one end of the resistor R116, one end of the capacitor C60, the emitter of the transistor Q6, the base of the transistor Q7, and one end of the resistor R123 are all electrically connected to the anode of the diode D21. The cathode of diode D23, the base of transistor Q6, and the other end of capacitor C60 are all electrically connected to one end of resistor R104, the other end of resistor R104 is electrically connected to the cathode of diode D24, the anode of diode D24 is electrically connected to the anode of voltage regulator diode DZ3, the cathode of voltage regulator diode DZ3 and the other end of resistor R123 are all electrically connected to the emitter of transistor Q7, the collector of transistor Q7, the collector of transistor Q6, the other end of resistor R116, the cathode of controllable voltage regulator source U19, and the gate of MOS tube Q5 are all electrically connected to the emitter of the photoreceiver of photocoupler U18, the other end of resistor R109 and the source of MOS tube Q5 are all electrically connected to one end of resistor R115, and the other end of resistor R115 is electrically connected to the reference electrode of controllable voltage regulator source U19.

[0063] In this embodiment, Figure 4As shown, the microcontroller 5 controls the switch of the dimming power supply module 8 through the photocoupler U18. When the photocoupler U18 is turned on (the dimming power supply module 8 is turned on), the MOS tube Q5 is turned on, so that the controllable voltage source U19 boosts the voltage to the resistor R115 to stabilize, and the DALI+ and DALI- ends maintain a constant current and constant voltage output. At the same time, when the base voltage of the transistor Q7 is greater than the emitter voltage, the transistor Q7 is turned on and the MOS tube Q5 is turned off to prevent the voltage on the voltage-stabilizing diode DZ3 from being burned out due to excessive voltage; when the DALI+ and DALI- terminals are reversed, the transistor Q6 is turned on, the MOS tube Q5 is turned off, and there is no output at the DALI+ and DALI- terminals; thereby achieving protection for the dimmer or dimming bus.

[0064] Further, the internal voltage conversion module 6 includes a voltage stabilizing chip U10, an AC / DC constant voltage chip U11, a capacitor C38, a capacitor CE1, a capacitor C40, a capacitor CE2, a capacitor C44, a capacitor CE4, a capacitor C39, a capacitor C36, a capacitor C41, a resistor R77, a diode D14, a transformer T2, a resistor R86, a resistor R87, a diode D15, a diode D16 and a voltage stabilizing diode DZ2; the power tube drain terminal of the AC / DC constant voltage chip U11 is used as the input terminal of the internal voltage conversion module 6, the output terminal of the voltage stabilizing chip U10 is used as the first output terminal of the internal voltage conversion module 6, and the opposite end of the primary side of the transformer T2 is used as the second output terminal of the internal voltage conversion module 6;

[0065] One end of capacitor C36 and one end of capacitor C41 are electrically connected to the drain end of the power tube of the AC / DC constant voltage chip U11, and the other end of capacitor C41 is connected to the GND ground end. The other end of capacitor C36, the anode of diode D15, the positive electrode of capacitor CE4, one end of capacitor C44, and one end of resistor R86 are electrically connected to the opposite end of the primary side of transformer T2, the cathode of diode D15 is electrically connected to the cathode of voltage regulator diode DZ2, one end of capacitor C39, the VCC end of AC / DC constant voltage chip U11, and the positive electrode of capacitor C44 are electrically connected to the positive electrode of capacitor C44. The voltage selection end of the C constant voltage chip U11 is electrically connected to the anode of the voltage zener diode DZ2, the GND end of the AC / DC constant voltage chip U11, the other end of the capacitor C39, and the cathode of the diode D16 are electrically connected to the same-name end of the primary side of the transformer T2, the current sampling end of the AC / DC constant voltage chip U11 is electrically connected to the GND end of the AC / DC constant voltage chip U11 via the resistor R87, and the anode of the diode D16, the cathode of the capacitor CE4, the other end of the capacitor C44, and the other end of the resistor R86 are all connected to the GND ground end;

[0066] The same-name terminal of the secondary side of the transformer T2 is electrically connected to the anode of the diode D14, the cathode of the diode D14 is electrically connected to the input terminal of the voltage regulator chip U10 via the resistor R77, the GND terminal of the voltage regulator chip U10 is connected to the SGND ground terminal, capacitor C40 and capacitor CE2 are connected in parallel between the input terminal of the voltage regulator chip U10 and the SGND ground terminal, and capacitor C38 and capacitor CE1 are connected in parallel between the output terminal of the voltage regulator chip U10 and the SGND ground terminal.

[0067] In this embodiment, Figure 5 As shown, the internal voltage conversion module 6 is composed of a transformer T2, a voltage stabilizing chip U10 (such as a 3.3V voltage stabilizing chip - AMS1117 chip) and its peripheral circuits and an AC / DC constant voltage chip U11 (such as a BP2522X chip, wherein the D terminal is the drain terminal of the power tube, the SEL terminal is the voltage selection terminal, and the CS terminal is the current sampling terminal) and its peripheral circuits. It is isolated by the transformer T2, and the voltage stabilizing chip U10 and its peripheral circuits and the AC / DC constant voltage chip U11 and its peripheral circuits respectively perform voltage conversion to meet the power supply voltage of the SGND ground terminal circuit and the GND ground terminal circuit of the main loop 1; if further voltage conversion is required, a voltage conversion circuit can be connected to the first output terminal or the second output terminal of the internal voltage conversion module 6 to achieve further voltage reduction to meet the power supply voltage requirements.

[0068] Furthermore, it also includes an external detection feedback module 4; the external detection access module 3 is electrically connected to the microcontroller 5 via the external detection feedback module 4;

[0069] The external detection access module 3 is also used to receive different types of detection signals from external sensors, generate the same type of feedback signals, and transmit the feedback signals to the microcontroller 5 through the external detection feedback module 4 .

[0070] In this embodiment, Figure 1 As shown, in the switching power supply, an external detection circuit is composed of an external voltage conversion module 2, an external detection access module 3 and an external detection feedback module 4, so the received external sensor signal needs to be fed back to the microcontroller 5; therefore, when an external sensor (such as a thermistor, an infrared temperature sensor, etc.) is connected, different types of detection signals are received from the external sensor, and the same type of feedback signals are generated and transmitted to the microcontroller 5 through the external detection feedback module 4, so that only one external detection circuit is set to uniformly convert the detection signals of different external sensors (such as level, PWM, resistance and other signals) into the same feedback signal (such as level, PWM, resistance and other signals) for identification by the microcontroller 5, which is low in cost and compatible with different external detections, greatly improving the external detection compatibility of the switching power supply, and further improving the intelligence of the switching power supply through rich external detection performance.

[0071] It should be noted that when multiple sensors are required for external detection, multiple external detection circuits can be added to increase the access points of the external sensors.

[0072] Furthermore, the external detection access module 3 includes a plurality of signal conversion chips U15 and a signal preprocessing circuit 31; the VCC terminal and the VIN terminal of the plurality of signal conversion chip U15 are electrically connected to the external voltage conversion module 2, the external sensor is electrically connected to the input terminal of the plurality of signal conversion chip U15 via the signal preprocessing circuit 31, and the output terminal of the plurality of signal conversion chip U15 is electrically connected to the microcontroller 5 via the external detection feedback module 4;

[0073] The multiple signal conversion chip U15 is used to receive different types of detection signals from external sensors through the signal preprocessing circuit 31, generate the same type of feedback signals, and transmit the feedback signals to the microcontroller 5 through the external detection feedback module 4.

[0074] In this embodiment, Figure 3 As shown, a variety of signal conversion chips U15 such as the XP1101 model chip (where the DIM terminal is the input terminal and the DRV terminal is the output terminal) support the conversion of level, resistance, and PWM signals into PWM signals for recognition by the microcontroller 5. Therefore, the external detection access module 3 is preferably composed of such a variety of signal conversion chips U15 and a signal preprocessing circuit 31, wherein the signal preprocessing circuit 31 is mainly used to preprocess the detection signal transmitted from the external sensor in order to obtain a stable detection signal.

[0075] Further, the external detection feedback module 4 includes a resistor R121, a capacitor C64, a resistor R125, a photoelectric coupler U21, a resistor R126, a capacitor C65 and a resistor R124; the anode of the light source of the photoelectric coupler U21 is electrically connected to the external detection access module 3 via the resistor R121, the cathode of the light source of the photoelectric coupler U21 is connected to the SGND ground terminal, and the resistor R125 and the capacitor C64 are connected in parallel between the anode and the cathode of the light source of the photoelectric coupler U21;

[0076] The collector of the photocoupler U21 light receiver is connected to a 3V3 power supply, the emitter of the photocoupler U21 light receiver is electrically connected to the microcontroller 5 via a resistor R124, the emitter of the photocoupler U21 light receiver is connected to the GND ground terminal, and a resistor R126 and a capacitor C65 are connected in parallel between the emitter of the photocoupler U21 light receiver and the GND ground terminal.

[0077] In this embodiment, the multiple signal conversion chip U15 is connected to the SGND ground terminal, which is different from the ground terminal of the microcontroller 5, and therefore isolated transmission is required. Therefore, the external detection feedback module 4 is composed of a photocoupler U21 and its peripheral circuits.

[0078] Furthermore, the preprocessing circuit 31 includes a capacitor C55, a capacitor C56, a resistor R108, a bidirectional TVS diode TVS1, an inductor L9 and an inductor L10; one end of the resistor R108 is electrically connected to the input end of the multiple signal conversion chip U15, one end of the resistor R108 is also electrically connected to one end of the capacitor C56, the other end of the resistor R108 and one end of the bidirectional TVS diode TVS1 are both electrically connected to one end of the inductor L9, the other end of the inductor L9 is electrically connected to one end of the capacitor C55, the other end of the capacitor C56, the other end of the bidirectional TVS diode TVS1 and one end of the inductor L10 are all connected to the SGND ground terminal, the other end of the inductor L10 is electrically connected to the other end of the capacitor C55, and one end and the other end of the capacitor C55 are both electrically connected to the external sensor.

[0079] In this embodiment, the preprocessing circuit 31 is preferably composed of capacitor C55, capacitor C56, resistor R108, bidirectional TVS diode TVS1, inductor L9 and inductor L10, which can perform impedance matching and shaping filtering on the detection signal transmitted by the thermistor (NTC) to obtain a stable detection signal.

[0080] Furthermore, it also includes a switch module 7; the second output end of the internal voltage conversion module 6 is also electrically connected to the input end of the switch module 7, the output end of the switch module 7 is electrically connected to the flyback drive module and the PFC module of the main circuit 1, and the control end of the switch module 7 is electrically connected to the microcontroller 5;

[0081] The microcontroller 5 controls the second conversion voltage to supply power to the flyback drive module and the PFC module of the main loop 1 through the switch module 7 .

[0082] In this embodiment, Figure 1 As shown, after adding the external detection circuit, since the switching power supply is also responsible for the power supply of the external detection circuit (mainly the external sensor), there may be a problem of excessive power consumption. It is also necessary to plan and control the power supply of other circuits inside the switching power supply to ensure that the switching power supply turns off some modules in the low-brightness dimming stage to reduce power consumption; therefore, since the flyback drive module and the PFC module of the main circuit 1 can be turned off according to different situations to reduce power consumption, a switch module 7 is added to control the power supply of the flyback drive module and the PFC module by the microcontroller 5 to realize the switch control of the module.

[0083] Further, the switch module 7 includes a resistor R78, a resistor R80, a resistor R76, a resistor R45, a capacitor C37, a transistor Q7 and a MOS transistor Q4; one end of the resistor R78 is used as a control end of the switch module 7, the drain of the MOS transistor Q4 is used as an input end of the switch module 7, and the source of the MOS transistor Q4 is used as an output end of the switch module 7;

[0084] The other end of the resistor R78 is electrically connected to the base of the transistor Q7, the collector of the transistor Q7 is electrically connected to the gate of the MOS transistor Q4, the emitter of the transistor Q7 is connected to the GND ground terminal, a resistor R80 and a capacitor C37 are connected in parallel between the base of the transistor Q7 and the GND ground terminal, a resistor R76 is connected in parallel between the collector of the transistor Q7 and the GND ground terminal, and a resistor R45 is connected in parallel between the gate and the drain of the MOS transistor Q4.

[0085] In this embodiment, Figure 6 As shown, the switch module 7 connects the second output end of the internal voltage conversion module 6 and the VCC end of the flyback drive module or the PFC module in the main circuit 1 through the MOS tube Q4 to form a power supply circuit, and then the microcontroller 5 controls the MOS tube Q4 through the transistor Q7 to realize the on-off control of the power supply circuit, so that the microcontroller 5 can control the switch of the flyback drive module and the PFC module.

[0086] Other structures and operations of a power supply system for a switching power supply according to an embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0087] In the description of this specification, the description with reference to the terms "embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0088] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A power supply system for a switching power supply, comprising a main circuit and a microcontroller, characterized in that: It also includes an external voltage conversion module, an external detection access module, an internal voltage conversion module and a dimming power supply module; the output end of the main circuit is electrically connected to the external voltage conversion module and the external detection access module in sequence, and the external detection access module is externally connected to an external sensor; the external voltage conversion module is also externally connected to other external devices; the external voltage conversion module is also electrically connected to the dimming power supply module, and the dimming power supply module is externally connected to a dimmer or a dimming bus; The external voltage conversion module is used for isolation, and is also used for converting the output voltage of the main circuit to power the other external devices and the dimming power supply module, and for powering the external sensor through the external detection access module; The dimming power supply module is also electrically connected to the microcontroller, and the microcontroller controls the dimming power supply module to supply power to the dimmer or the dimming bus; The output end of the main circuit is also electrically connected to the input end of the internal voltage conversion module, and the first output end and the second output end of the internal voltage conversion module are electrically connected to the SGND ground terminal circuit and the GND ground terminal circuit of the main circuit respectively; The internal voltage conversion module is used for isolation and is also used for performing voltage conversion on the output voltage of the main circuit to generate a first conversion voltage and a second conversion voltage, wherein the first conversion voltage and the second conversion voltage respectively power the SGND ground terminal circuit and the GND ground terminal circuit of the main circuit.

2. A power supply system for a switching power supply according to claim 1, characterized in that: The external voltage conversion module includes a capacitor C49, a transformer T3, a flyback power supply processing circuit, a flyback feedback circuit, a first output processing circuit and a second output processing circuit; after the capacitor C49 is connected in parallel between the output end of the main loop 1 and the GND ground end, it is electrically connected to the primary side of the transformer T3; the secondary side A of the transformer T3 is electrically connected to the other external devices via the first output processing circuit, and the flyback feedback circuit is electrically connected between the primary side of the transformer T3 and the first output processing circuit; the first output processing circuit is also electrically connected to the dimming power supply module; The secondary side C of the transformer T3 is electrically connected to the flyback feedback circuit via the flyback power supply processing circuit; The secondary side B of the transformer T3 is electrically connected to the external detection access module via the second output processing circuit.

3. A power supply system for a switching power supply according to claim 1, characterized in that: The dimming power supply module includes a resistor R101, a photocoupler U18, a resistor R103, a resistor R106, a resistor R107, a resistor R115, a resistor R109, a resistor R103, a resistor R116, a resistor R104, a resistor R123, a diode D22, a MOS tube Q5, a controllable voltage source U19, a diode D21, a diode D23, a diode D24, a voltage regulator diode DZ3, a capacitor C60, a transistor Q6 and a transistor Q7; one end of the resistor R101 is electrically connected to the microcontroller, the drain of the MOS tube Q5 is electrically connected to the external voltage conversion module, and the cathode of the diode D21 and the cathode of the diode D24 are both electrically connected to the dimmer or the dimming bus; The other end of the resistor R101 is electrically connected to the anode of the light source of the photoelectric coupler U18, the cathode of the light source of the photoelectric coupler U18 is connected to the GND ground terminal, the light receiver collector of the photoelectric coupler U18 is electrically connected to one end of the resistor R103, the other end of the resistor R103, one end of the resistor R106, and one end of the resistor R107 are all electrically connected to the cathode of the diode D22, the other end of the resistor R106 and the other end of the resistor R107 are all electrically connected to the drain of the MOS tube Q5, the anode of the diode D22, the anode of the diode D23, one end of the resistor R109, the anode of the controllable voltage regulator U19, one end of the resistor R116, one end of the capacitor C60, the emitter of the transistor Q6, the base of the transistor Q7, and one end of the resistor R123 are all electrically connected to the anode of the diode D21. The cathode of the diode D23, the base of the transistor Q6, and the other end of the capacitor C60 are all electrically connected to one end of the resistor R104, the other end of the resistor R104 is electrically connected to the cathode of the diode D24, the anode of the diode D24 is electrically connected to the anode of the voltage-stabilizing diode DZ3, the cathode of the voltage-stabilizing diode DZ3 and the other end of the resistor R123 are all electrically connected to the emitter of the transistor Q7, the collector of the transistor Q7, the collector of the transistor Q6, the other end of the resistor R116, the cathode of the controllable voltage-stabilizing source U19, and the gate of the MOS tube Q5 are all electrically connected to the emitter of the light receiver of the photocoupler U18, the other end of the resistor R109 and the source of the MOS tube Q5 are all electrically connected to one end of the resistor R115, and the other end of the resistor R115 is electrically connected to the reference electrode of the controllable voltage-stabilizing source U19.

4. A power supply system for a switching power supply according to claim 1, characterized in that: The internal voltage conversion module includes a voltage stabilizing chip U10, an AC / DC constant voltage chip U11, a capacitor C38, a capacitor CE1, a capacitor C40, a capacitor CE2, a capacitor C44, a capacitor CE4, a capacitor C39, a capacitor C36, a capacitor C41, a resistor R77, a diode D14, a transformer T2, a resistor R86, a resistor R87, a diode D15, a diode D16 and a voltage stabilizing diode DZ2; the power tube drain terminal of the AC / DC constant voltage chip U11 is used as the input terminal of the internal voltage conversion module, the output terminal of the voltage stabilizing chip U10 is used as the first output terminal of the internal voltage conversion module, and the opposite end of the primary side of the transformer T2 is used as the second output terminal of the internal voltage conversion module; One end of the capacitor C36 and one end of the capacitor C41 are electrically connected to the drain end of the power tube of the AC / DC constant voltage chip U11, the other end of the capacitor C41 is connected to the GND ground end, the other end of the capacitor C36, the anode of the diode D15, the positive electrode of the capacitor CE4, one end of the capacitor C44, and one end of the resistor R86 are electrically connected to the opposite end of the primary side of the transformer T2, the cathode of the diode D15 is electrically connected to the cathode of the voltage regulator diode DZ2, one end of the capacitor C39, the VCC end of the AC / DC constant voltage chip U11, and the positive electrode of the capacitor C41 are electrically connected to the VCC end of the AC / DC constant voltage chip U11. The voltage selection end of the C / DC constant voltage chip U11 is electrically connected to the anode of the voltage zener diode DZ2, the GND end of the AC / DC constant voltage chip U11, the other end of the capacitor C39, and the cathode of the diode D16 are electrically connected to the same-name end of the primary side of the transformer T2, the current sampling end of the AC / DC constant voltage chip U11 is electrically connected to the GND end of the AC / DC constant voltage chip U11 via the resistor R87, and the anode of the diode D16, the cathode of the capacitor CE4, the other end of the capacitor C44, and the other end of the resistor R86 are all connected to the GND ground end; The same-name terminal of the secondary side of the transformer T2 is electrically connected to the anode of the diode D14, the cathode of the diode D14 is electrically connected to the input terminal of the voltage stabilizing chip U10 via the resistor R77, the GND terminal of the voltage stabilizing chip U10 is connected to the SGND ground terminal, the capacitor C40 and the capacitor CE2 are connected in parallel between the input terminal of the voltage stabilizing chip U10 and the SGND ground terminal, and the capacitor C38 and the capacitor CE1 are connected in parallel between the output terminal of the voltage stabilizing chip U10 and the SGND ground terminal.

5. A power supply system for a switching power supply according to claim 1, characterized in that: It also includes an external detection feedback module; the external detection access module is electrically connected to the microcontroller via the external detection feedback module; The external detection access module is also used to receive different types of detection signals from the external sensor, generate the same type of feedback signal, and transmit the feedback signal to the microcontroller through the external detection feedback module.

6. A power supply system for a switching power supply according to claim 5, characterized in that: The external detection access module includes a plurality of signal conversion chips U15 and a signal preprocessing circuit; the VCC terminal and the VIN terminal of the plurality of signal conversion chips U15 are electrically connected to the external voltage conversion module, the external sensor is electrically connected to the input terminal of the plurality of signal conversion chips U15 via the signal preprocessing circuit, and the output terminal of the plurality of signal conversion chips U15 is electrically connected to the microcontroller via the external detection feedback module; The multiple signal conversion chip U15 is used to receive different types of detection signals from the external sensor through the signal preprocessing circuit, generate the same type of feedback signals, and transmit the feedback signals to the microcontroller through the external detection feedback module.

7. A power supply system for a switching power supply according to claim 5, characterized in that: The external detection feedback module includes a resistor R121, a capacitor C64, a resistor R125, a photoelectric coupler U21, a resistor R126, a capacitor C65 and a resistor R124; the anode of the light source of the photoelectric coupler U21 is electrically connected to the external detection access module via the resistor R121, the cathode of the light source of the photoelectric coupler U21 is connected to the SGND ground terminal, and the resistor R125 and the capacitor C64 are connected in parallel between the anode and the cathode of the light source of the photoelectric coupler U21; The collector of the photoelectric coupler U21 light receiver is connected to a 3V3 power supply, the emitter of the photoelectric coupler U21 light receiver is electrically connected to the microcontroller via the resistor R124, the emitter of the photoelectric coupler U21 light receiver is connected to the GND ground terminal, and the resistor R126 and the capacitor C65 are connected in parallel between the emitter of the photoelectric coupler U21 light receiver and the GND ground terminal.

8. A power supply system for a switching power supply according to claim 6, characterized in that: The preprocessing circuit includes capacitor C55, capacitor C56, resistor R108, bidirectional TVS diode TVS1, inductor L9 and inductor L10; one end of the resistor R108 is electrically connected to the input end of the multiple signal conversion chip U15, one end of the resistor R108 is also electrically connected to one end of the capacitor C56, the other end of the resistor R108 and one end of the bidirectional TVS diode TVS1 are both electrically connected to one end of the inductor L9, the other end of the inductor L9 is electrically connected to one end of the capacitor C55, the other end of the capacitor C56, the other end of the bidirectional TVS diode TVS1 and one end of the inductor L10 are all connected to the SGND ground terminal, the other end of the inductor L10 is electrically connected to the other end of the capacitor C55, and one end and the other end of the capacitor C55 are both electrically connected to the external sensor.

9. A power supply system for a switching power supply according to claim 1, characterized in that: It also includes a switch module; the second output end of the internal voltage conversion module is also electrically connected to the input end of the switch module, the output end of the switch module is electrically connected to the flyback drive module and the PFC module of the main circuit respectively, and the control end of the switch module is electrically connected to the microcontroller; The microcontroller controls the second conversion voltage to supply power to the flyback drive module and the PFC module of the main loop through the switch module.

10. A power supply system for a switching power supply according to claim 9, characterized in that: The switch module includes a resistor R78, a resistor R80, a resistor R76, a resistor R45, a capacitor C37, a transistor Q7 and a MOS transistor Q4; one end of the resistor R78 is used as a control end of the switch module, the drain of the MOS transistor Q4 is used as an input end of the switch module, and the source of the MOS transistor Q4 is used as an output end of the switch module; The other end of the resistor R78 is electrically connected to the base of the transistor Q7, the collector of the transistor Q7 is electrically connected to the gate of the MOS transistor Q4, the emitter of the transistor Q7 is connected to the GND ground terminal, the resistor R80 and the capacitor C37 are connected in parallel between the base of the transistor Q7 and the GND ground terminal, the resistor R76 is connected in parallel between the collector of the transistor Q7 and the GND ground terminal, and the resistor R45 is connected in parallel between the gate and the drain of the MOS transistor Q4.

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