Primary side feedback switching power supply

Abstract

The utility model relates to the technical field of switching power supplies, in particular to a switching power supply with primary side feedback, which comprises an input rectifier module, a high-power-factor constant-voltage driving module, a transformer T1, a secondary side filter module, a constant-current dimming module with protection and a microcontroller. The input rectifier module, the high-power-factor constant-voltage driving module and a primary winding of the transformer T1 are electrically connected in sequence, and the high-power-factor constant-voltage driving module is electrically connected with a primary auxiliary winding of the transformer T1; a secondary winding of the transformer T1, the secondary filtering module and the constant-current dimming module with protection are electrically connected in sequence, and the constant-current dimming module with protection is electrically connected with the microcontroller; the high-power-factor constant-voltage driving module comprises a gallium nitride MOS tube Q1; the high-power-factor constant-voltage driving module drives the gallium nitride MOS tube Q1 to realize constant-voltage output; the constant-current dimming module with the protection function is composed of a chip with a protection function and a peripheral circuit of the chip. The problems that the response speed is low and the miniaturization degree is limited are solved.

Description

Technical Field

[0001] This utility model relates to the field of switching power supply technology, and in particular to a primary-side feedback switching power supply. Background Technology

[0002] Currently, switching power supplies typically employ secondary-side feedback. This involves sampling the output voltage through the secondary voltage output terminal of the transformer, then converting the sampled signal into a current signal via an isolation circuit (such as an optocoupler), and finally feeding it back to the primary-side control chip. Compared to primary-side feedback switching power supplies, which extract the output voltage signal from the secondary coil through the auxiliary coil of the transformer, this approach results in higher standby power consumption, more feedback devices, more complex circuitry, and a greater susceptibility to problems. Therefore, given the current market demand for miniaturization in switching power supplies, primary-side feedback is preferred over secondary-side feedback.

[0003] However, since primary-side feedback requires detecting the output voltage through changes in the primary magnetic field of the transformer, its response speed is relatively slow, which may not be suitable for applications requiring fast response. Improving the response speed would require adding a series of processing circuits, making it impossible to simultaneously meet the requirements of miniaturization and increased response speed. More importantly, existing primary-side feedback switching power supplies also have multiple protection circuits, resulting in a complex circuit structure and limited miniaturization capabilities. Utility Model Content

[0004] To address the aforementioned shortcomings, the purpose of this invention is to propose a primary-side feedback switching power supply, which solves the problems of slow response speed and limited miniaturization.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A primary-side feedback switching power supply includes an input rectifier module, a high power factor constant voltage drive module, a transformer T1, a secondary-side filter module, a constant current dimming module with protection, and a microcontroller. The input rectifier module, the high power factor constant voltage drive module, and the primary winding of the transformer T1 are sequentially electrically connected, and the high power factor constant voltage drive module is electrically connected to the primary auxiliary winding of the transformer T1. The high power factor constant voltage drive module receives voltage feedback from the primary auxiliary winding of the transformer T1. The secondary winding of the transformer T1, the secondary-side filter module, and the constant current dimming module with protection are sequentially electrically connected, and the constant current dimming module with protection is electrically connected to the microcontroller. The constant current dimming module with protection receives dimming signals from the microcontroller.

[0007] The high power factor constant voltage drive module is equipped with a gallium nitride MOSFET Q1; the high power factor constant voltage drive module drives the gallium nitride MOSFET Q1 to achieve constant voltage output;

[0008] The protected constant current dimming module consists of a chip with protection function and its peripheral circuits.

[0009] Furthermore, it also includes a first detection module and a second detection module; the first detection module is electrically connected between the secondary-side filter module and the microcontroller, and is used to feed back the voltage signal of the secondary-side filter module to the microcontroller;

[0010] The second detection module is electrically connected between the input rectifier module and the microcontroller, and is used to feed back the voltage signal of the input rectifier module to the microcontroller.

[0011] Furthermore, the high power factor constant voltage drive module also includes resistors R14, R17, R19, and R36, MOSFET Q2, capacitor C11, diode D1, capacitor C2, capacitor C4, capacitor C9, high power factor drive chip U3, RCD snubber circuit, power supply circuit, voltage detection circuit, and first drive and current detection circuit; the output terminal of the input rectifier module is electrically connected to the same-name terminal of the primary winding of the transformer T1, and the RCD snubber circuit is connected in parallel between the same-name terminal and the opposite-name terminal of the primary winding of the transformer T1;

[0012] The output terminal of the input rectifier module is connected to the gate of the MOSFET Q2 after being connected in series with resistors R14 and R17. The output terminal of the input rectifier module is connected to the drain of the MOSFET Q2 after being connected in series with resistors R36 and R19. The gate of the MOSFET Q2 is connected to the VIN terminal of the high power factor driver chip U3. The capacitor C11 is connected in parallel between the gate of the MOSFET Q2 and the GND terminal. The source of the MOSFET Q2 is connected to the anode of the diode D1. The VCC terminal of the high power factor driver chip U3 is connected to the cathode of the diode D1. The capacitor C2 is connected in parallel between the VCC terminal and the GND terminal of the high power factor driver chip U3. The capacitor C4 is connected in parallel between the VDD terminal and the GND terminal of the high power factor driver chip U3. The GND terminal of the high power factor driver chip U3 is connected to the GND terminal.

[0013] The opposite-named end of the primary auxiliary winding of the transformer T1 is connected to the GND ground terminal, and the same-named end of the primary auxiliary winding of the transformer T1 is electrically connected to the VCC terminal of the high power factor drive chip U3 through the power supply circuit 22.

[0014] The VSNS terminal of the high power factor drive chip U3 is electrically connected to the same-name terminal of the primary auxiliary winding of the transformer T1 via the voltage detection circuit.

[0015] The opposite terminal of the primary winding of the transformer T1 is electrically connected to the drain of the gallium nitride MOS transistor Q1. The capacitor C9 is connected in parallel between the drain and source of the gallium nitride MOS transistor Q1. The OUT terminal and ISNS terminal of the high power factor driver chip U3 are electrically connected to the drive terminal and feedback terminal of the first drive and current detection circuit, respectively. The output terminal and input terminal of the first drive and current detection circuit are electrically connected to the gate and source of the gallium nitride MOS transistor Q1, respectively.

[0016] Furthermore, the first driving and current detection circuit includes resistors R2 and R5, diode D9, resistors R6 and R7, capacitor C6, resistor R49, resistor R50, resistor R3, resistor R4, resistor R16, and capacitor C7; the cathode of diode D9 and one end of resistor R5 are electrically connected to the OUT terminal of the high power factor driving chip U3, the anode of diode D9 is electrically connected to one end of resistor R2, and the other ends of resistors R5, R2, R6, and R7 are all electrically connected to the gate of the gallium nitride MOSFET Q1. The other end is electrically connected to one end of the capacitor C6. The other end of the capacitor C6, the other end of the resistor R6, one end of the resistor R49, one end of the resistor R50, one end of the resistor R3, one end of the resistor R4, and one end of the resistor R16 are all electrically connected to the source of the gallium nitride MOS transistor Q1. The other end of the resistor R16 and one end of the capacitor C7 are all electrically connected to the ISNS terminal of the high power factor driver chip U3. The other ends of the resistor R49, the other ends of the resistor R50, the other ends of the resistor R3, the other ends of the resistor R4, and the other ends of the capacitor C7 are all connected to the GND ground terminal.

[0017] Furthermore, the voltage detection circuit includes resistors R15, R21, and R22, diode D10, and capacitor C12; the same-name terminal of the primary auxiliary winding of transformer T1 is electrically connected to one end of resistor R21, the other end of resistor R21 and one end of resistor R22 are both electrically connected to the cathode of diode D10, the other end of resistor R22, one end of resistor R15 and one end of capacitor C12 are all electrically connected to the VSNS terminal of high power factor drive chip U3, and the anode of diode D10, the other end of resistor R15, and the other end of capacitor C12 are all connected to GND ground.

[0018] Furthermore, the power supply circuit includes a resistor R79, a diode D2, and a capacitor EC1; the primary auxiliary winding of the transformer T1 is electrically connected to the anode of the diode D2, the cathode of the diode D2 is connected in series with the resistor R79, and then electrically connected to the VCC terminal of the high power factor drive chip U3 and the positive terminal of the capacitor EC1, and the negative terminal of the capacitor EC1 is connected to the GND ground terminal.

[0019] Furthermore, the protected constant current dimming module includes a resistor R42, a MOSFET Q4, a protected constant current dimming chip U4, a constant current output circuit, and a second drive and current detection circuit. The output terminal of the secondary-side filter module is electrically connected to the input terminal of the constant current output circuit. The output terminal of the secondary-side filter module is also connected in series with the resistor R42 and then electrically connected to the VIN terminal of the protected constant current dimming chip U4. The OUT terminal and ISNS terminal of the protected constant current dimming chip U4 are respectively electrically connected to the drive terminal and feedback terminal of the second drive and current detection circuit. The output terminal and input terminal of the second drive and current detection circuit are respectively electrically connected to the gate and source of the MOSFET Q4. The drain of the MOSFET Q4 is electrically connected to the input terminal of the inductor in the constant current output circuit 41. The RX terminal and TX terminal of the protected constant current dimming chip U4 are both electrically connected to the microcontroller.

[0020] Furthermore, the first detection module includes diodes D5 and D6, resistors R80, R81, R82, R88, R85, R83, R84, R28, capacitor C80, adjustable voltage regulator U5, and optocoupler U9. The anodes of diodes D5 and D6 are electrically connected to the first and second input terminals of the rectifier bridge in the input rectifier module, respectively. The cathodes of diodes D5 and D6 are both electrically connected to one end of resistor R80, and the other end of resistor R80 is connected in series. After resistors R81 and R28, one end of resistor R82 is electrically connected; one end of resistor R82 and one end of capacitor C80 are both electrically connected to the reference terminal of adjustable voltage regulator U5; the anode of adjustable voltage regulator U5, the other end of resistor R82, and the other end of capacitor C80 are all connected to GND ground; the cathode of adjustable voltage regulator U5 and the cathode of optocoupler U9 are electrically connected; the anode of optocoupler U9 is connected in series with resistor R85 and then connected to VDD power supply; resistor R88 is connected in parallel between the anode and cathode of optocoupler U9.

[0021] The collector of the optocoupler U9 is connected to a 3V3 power supply. The emitter of the optocoupler U9 and one end of the resistor R83 are electrically connected to one end of the resistor R84. The other end of the resistor R83 is connected to the SGND ground terminal. One end of the resistor R84 is electrically connected to the microcontroller.

[0022] Furthermore, the second detection module includes resistor R64, resistor R66, and capacitor C27; the output terminal of the secondary side filter module is electrically connected to one end of resistor R64, the other end of resistor R64, one end of resistor R66, and one end of capacitor C27 are all electrically connected to the microcontroller, and the other end of resistor R66 and the other end of capacitor C27 are both connected to the SGND ground terminal.

[0023] The technical solution provided by this utility model can include the following beneficial effects: the main circuit of the switching power supply with constant voltage and constant current output is composed of an input rectifier module, a high power factor constant voltage drive module, a transformer T1, a secondary filter module, and a constant current dimming module with protection. The microcontroller controls the dimming of the constant current dimming module with protection. The constant voltage output is achieved by using a gallium nitride MOSFET Q1 in the high power factor constant voltage drive module. By utilizing the low power consumption and high frequency switching characteristics of the gallium nitride MOSFET Q1 and the high working efficiency of the high power factor constant voltage drive module, the response speed of the switching power supply is greatly improved, making the switching power supply suitable for fast-response application scenarios. At the same time, the constant current dimming module with protection is composed of a chip with protection function and its peripheral circuits. A single chip integrates multiple protections such as overvoltage and short circuit, which can replace multiple protection circuits, greatly reducing the complexity of the switching power supply circuit structure and further reducing the size of the switching power supply. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a primary-side feedback switching power supply according to one embodiment of the present invention.

[0025] Figure 2 Is it like this? Figure 1 The circuit diagram shown is for the input rectifier module and the high power factor constant voltage drive module.

[0026] Figure 3 Is it like this? Figure 1 The circuit diagram of the secondary-side filter module is shown.

[0027] Figure 4 Is it like this? Figure 1 The circuit diagram shown is for a constant current dimming module with protection.

[0028] Figure 5 Is it like this? Figure 1 The circuit diagram of the first detection module is shown below.

[0029] Figure 6 Is it like this? Figure 1 The circuit diagram of the second detection module is shown.

[0030] The circuit includes: input rectifier module 1, high power factor constant voltage drive module 2, transformer T1, secondary filter module 3, constant current dimming module with protection 4, microcontroller 5, first detection module 6, second detection module 7, resistors R14, R17, R19, R36, MOSFET Q2, capacitor C11, diode D1, capacitor C2, capacitor C4, capacitor C9, high power factor drive chip U3, RCD absorption circuit 21, power supply circuit 22, voltage detection circuit 23, first drive and current detection circuit 24, resistors R2, R5, diode D9, resistors R6, R7, capacitor C6, resistor R49, and resistor R 50. Resistors R3, R4, R16, C7, R15, R21, R22, D10, C12, R79, D2, EC1, R42, Q4, U4 (with protection), constant current dimming chip, constant current output circuit 41, second drive and current detection circuit 42, D5, D6, R80, R81, R82, R88, R85, R83, R84, R28, C80, U5 (adjustable voltage regulator), U9 (optocoupler), R64, R66, C27. Detailed Implementation

[0031] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein 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 accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0032] In the description of embodiments of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of embodiments of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] In the description of the embodiments of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this utility model according to the specific circumstances.

[0034] The following is combined Figures 1 to 6 This describes a primary-side feedback switching power supply according to an embodiment of the present invention.

[0035] A primary-side feedback switching power supply includes an input rectifier module 1, a high power factor constant voltage drive module 2, a transformer T1, a secondary-side filter module 3, a constant current dimming module 4 with protection, and a microcontroller 5. The input rectifier module 1, the high power factor constant voltage drive module 2, and the primary winding of the transformer T1 are electrically connected in sequence, and the high power factor constant voltage drive module 2 is electrically connected to the primary auxiliary winding of the transformer T1. The high power factor constant voltage drive module 2 receives voltage feedback from the primary auxiliary winding of the transformer T1. The secondary winding of the transformer T1, the secondary-side filter module 3, and the constant current dimming module 4 with protection are electrically connected in sequence, and the constant current dimming module 4 with protection is electrically connected to the microcontroller 5. The constant current dimming module 4 with protection receives dimming signals from the microcontroller 5.

[0036] The high power factor constant voltage drive module 2 is equipped with a gallium nitride MOSFET Q1; the high power factor constant voltage drive module 2 drives the gallium nitride MOSFET Q1 to achieve constant voltage output;

[0037] The protected constant current dimming module 4 consists of a chip with protection function and its peripheral circuits.

[0038] This utility model proposes a preferred embodiment of a primary-side feedback switching power supply, such as... Figure 1As shown, the main circuit of the switching power supply with constant voltage and constant current output consists of an input rectifier module 1, a high power factor constant voltage drive module 2, a transformer T1, a secondary filter module 3, and a constant current dimming module 4 with protection. A microcontroller 5 (such as an MCU) controls the dimming of the constant current dimming module 4 with protection. The high power factor constant voltage drive module 2 uses a gallium nitride MOSFET Q1 to achieve constant voltage output. By utilizing the low power consumption and high frequency switching characteristics of the gallium nitride MOSFET Q1 and the high operating efficiency of the high power factor constant voltage drive module 2, the response speed of the switching power supply is greatly improved, making the switching power supply suitable for fast-response application scenarios. At the same time, the constant current dimming module 4 with protection is composed of a chip with protection function and its peripheral circuits. A single chip integrates multiple protections such as overvoltage and short circuit, which can replace multiple protection circuits, greatly reducing the complexity of the switching power supply circuit structure and allowing the size of the switching power supply to be further reduced.

[0039] Furthermore, it also includes a first detection module 6 and a second detection module 7; the first detection module 6 is electrically connected between the secondary-side filter module 3 and the microcontroller 5, and is used to feed back the voltage signal of the secondary-side filter module 3 to the microcontroller 5;

[0040] The second detection module 7 is electrically connected between the input rectifier module 1 and the microcontroller 5, and is used to feed back the voltage signal of the input rectifier module 1 to the microcontroller 5.

[0041] In this embodiment, the protection mechanism based on the switching power supply is executed by the constant current dimming module 4 with protection, so that the protection detection of the switching power supply is concentrated at the output end. There are detection blind spots at the input end and intermediate links of the switching power supply. To address this, a first detection module 6 and a second detection module 7 are set up to supplement the detection feedback to the microcontroller 5. The microcontroller 5 then determines and controls the constant current dimming module 4 with protection to execute the protection, thereby achieving linkage and improving the protection mechanism of the switching power supply.

[0042] Furthermore, the high power factor constant voltage drive module 2 also includes resistors R14, R17, R19, and R36, MOSFET Q2, capacitor C11, diode D1, capacitor C2, capacitor C4, capacitor C9, high power factor drive chip U3, RCD absorption circuit 21, power supply circuit 22, voltage detection circuit 23, and first drive and current detection circuit 24; the output terminal of the input rectifier module 1 is electrically connected to the same-name terminal of the primary winding of transformer T1, and the RCD absorption circuit 21 is connected in parallel between the same-name terminal and the opposite-name terminal of the primary winding of transformer T1;

[0043] The output terminal of the input rectifier module 1 is connected to the gate of MOSFET Q2 after being connected in series with resistors R14 and R17. The output terminal of the input rectifier module 1 is connected to the drain of MOSFET Q2 after being connected in series with resistors R36 and R19. The gate of MOSFET Q2 is connected to the VIN terminal of high power factor driver chip U3. A capacitor C11 is connected in parallel between the gate of MOSFET Q2 and GND. The source of MOSFET Q2 is connected to the anode of diode D1. The VCC terminal of high power factor driver chip U3 is connected to the cathode of diode D1. A capacitor C2 is connected in parallel between the VCC terminal of high power factor driver chip U3 and GND. A capacitor C4 is connected in parallel between the VDD terminal of high power factor driver chip U3 and GND. The GND terminal of high power factor driver chip U3 is connected to GND.

[0044] The opposite-named terminal of the primary auxiliary winding of transformer T1 is connected to the GND ground terminal, and the same-named terminal of the primary auxiliary winding of transformer T1 is electrically connected to the VCC terminal of the high power factor drive chip U3 through the power supply circuit 22.

[0045] The VSNS terminal of the high power factor drive chip U3 is electrically connected to the same terminal of the primary auxiliary winding of transformer T1 via voltage detection circuit 23.

[0046] The opposite terminal of the primary winding of transformer T1 is electrically connected to the drain of gallium nitride MOSFET Q1. A capacitor C9 is connected in parallel between the drain and source of gallium nitride MOSFET Q1. The OUT terminal and ISNS terminal of high power factor driver chip U3 are electrically connected to the drive terminal and feedback terminal of the first drive and current detection circuit 24, respectively. The output terminal and input terminal of the first drive and current detection circuit 24 are electrically connected to the gate and source of gallium nitride MOSFET Q1, respectively.

[0047] In this embodiment, as Figure 2 As shown, the input rectifier module 1 typically consists of a safety circuit (the input circuit of the rectifier bridge BD1), the rectifier bridge BD1, and a Π-type filter (capacitor CB7, inductor L5, resistor R80, and capacitor CB8) to achieve AC to DC rectification and filtering. When the output voltage of the input rectifier module 1 is increased to a certain level, the MOSFET Q2 is turned on and transmitted to the high power factor driver chip U3 to achieve efficient operation.

[0048] Taking the XP3359G chip as an example, the high power factor drive chip U3 uses the voltage received at its VCC and VIN terminals to determine whether it starts up and to ensure operational stability. Its digital core analyzes the waveform of the primary auxiliary winding of transformer T1 in real time to control the gallium nitride MOSFET Q1, achieving primary-side control of transformer T1. Phase compensation is performed internally, ensuring loop stability under any input / output conditions without the need for external compensation components. Furthermore, based on its real-time monitoring of the voltage of the primary auxiliary winding of transformer T1 and the current of gallium nitride MOSFET Q1, excellent power factor (PF) / thunder factor (THD) can be achieved regardless of the transformer inductance value. In addition, the chip's digital core performs reverse phase shift adjustment of the flyback through internal calculations to reduce the impact of EMI capacitors on PF / THD, greatly improving the chip's driving efficiency for gallium nitride MOSFET Q1 and thus increasing the response speed of the switching power supply.

[0049] It should be noted that the RCD absorption circuit 21 is mainly used to absorb high-frequency oscillations on the primary side of transformer T1, and its circuit structure can be as follows: Figure 2 As shown, other RCD snubber circuit structures are also possible, and are not limited here.

[0050] Furthermore, the first driving and current detection circuit 24 includes resistors R2 and R5, diode D9, resistors R6 and R7, capacitor C6, resistors R49, R50, R3, R4, R16, and capacitor C7. The cathode of diode D9 and one end of resistor R5 are electrically connected to the OUT terminal of the high power factor driving chip U3. The anode of diode D9 is electrically connected to one end of resistor R2. The other ends of resistors R5, R2, R6, and R7 are all electrically connected to the gate of gallium nitride MOSFET Q1. The other end of resistor R7 is electrically connected to one end of capacitor C6. The other end of capacitor C6, the other end of resistor R6, one end of resistor R49, one end of resistor R50, one end of resistor R3, one end of resistor R4, and one end of resistor R16 are all electrically connected to the source of gallium nitride MOSFET Q1. The other end of resistor R16 and one end of capacitor C7 are both electrically connected to the ISNS terminal of high power factor driver chip U3. The other ends of resistor R49, resistor R50, resistor R3, resistor R4, and capacitor C7 are all connected to GND ground.

[0051] In this embodiment, the first driving and current detection circuit 24 consists of resistors R2 and R5, diode D9, resistors R6 and R7, and capacitor C6, which form a driving circuit to directly drive the gallium nitride MOS transistor Q1. The current detection circuit consists of resistors R49, R50, R3, R4, R16, and capacitor C7, which feeds back the current signal to the high power factor driving chip U3.

[0052] Furthermore, the voltage detection circuit 23 includes resistors R15, R21, and R22, diode D10, and capacitor C12; the same-name terminal of the primary auxiliary winding of transformer T1 is electrically connected to one end of resistor R21, the other end of resistor R21 and one end of resistor R22 are both electrically connected to the cathode of diode D10, the other end of resistor R22, one end of resistor R15, and one end of capacitor C12 are all electrically connected to the VSNS terminal of high power factor drive chip U3, and the anode of diode D10, the other end of resistor R15, and the other end of capacitor C12 are all connected to the GND ground terminal.

[0053] In this embodiment, the voltage detection circuit 23 is preferably composed of resistors R15, R21, R22, diode D10 and capacitor C12, which performs voltage sampling on the primary auxiliary winding and provides voltage regulation and filtering feedback to the high power factor driver chip U3.

[0054] Furthermore, the power supply circuit 22 includes a resistor R79, a diode D2, and a capacitor EC1; the primary auxiliary winding of the transformer T1 is electrically connected to the anode of the diode D2, the cathode of the diode D2 is connected to the VCC terminal of the high power factor drive chip U3 and the positive terminal of the capacitor EC1 after being connected in series with the resistor R79, and the negative terminal of the capacitor EC1 is connected to the GND ground terminal.

[0055] In this embodiment, after the high power factor drive chip U3 is started and stabilized, it is powered by the primary auxiliary winding. Preferably, the power supply circuit 22, consisting of resistor R79, diode D2 and capacitor EC1, obtains a unidirectional stable voltage.

[0056] Furthermore, the protected constant current dimming module 4 includes a resistor R42, a MOSFET Q4, a protected constant current dimming chip U4, a constant current output circuit 41, and a second drive and current detection circuit 42. The output terminal of the secondary-side filter module 3 is electrically connected to the input terminal of the constant current output circuit 41. The output terminal of the secondary-side filter module 3 is also connected to the VIN terminal of the protected constant current dimming chip U4 after being connected in series with the resistor R42. The OUT terminal and ISNS terminal of the protected constant current dimming chip U4 are electrically connected to the drive terminal and feedback terminal of the second drive and current detection circuit 42, respectively. The output terminal and input terminal of the second drive and current detection circuit 42 are electrically connected to the gate and source of the MOSFET Q4, respectively. The drain of the MOSFET Q4 is electrically connected to the input terminal of the inductor in the constant current output circuit 41. The RX terminal and TX terminal of the protected constant current dimming chip U4 are both electrically connected to the microcontroller 5.

[0057] In this embodiment, as Figures 3 to 4 As shown, the secondary filter module 3 is typically as follows: Figure 3As shown, the secondary signal of transformer T1 is rectified and filtered and output to constant current output circuit 41. Then, through the protected constant current dimming chip U4 of the protected constant current dimming module 4, the second drive and current detection circuit 42 continuously turns the MOS transistor Q4 on and off, generating a pulsating voltage. After passing through the LC filter circuit (i.e., constant current output circuit 41), the pulsating voltage is converted into a more stable DC voltage and delivered to the load. Its various protection functions are realized by the protection functions integrated by the protected constant current dimming chip U4. For example, the XP2116M chip is used, and the integrated protection functions include: output overvoltage protection (OVP), output short circuit protection (OSP), input overvoltage protection (Vin OVP), input undervoltage protection (VinUVP), over-temperature protection (OTP), and over-temperature current derating.

[0058] It should be noted that in the second driving and current detection circuit 42, the driving circuit is preferably composed of resistor R30, resistor R32, diode D11, and resistor R34 to directly drive the MOS transistor Q4, and the current detection circuit is composed of resistor R41, resistor R40, resistor R39, resistor R38, resistor R37 and capacitor C17 to feed back the current signal to the protected constant current dimming chip U4.

[0059] Furthermore, the first detection module 6 includes diodes D5 and D6, resistors R80, R81, R82, R88, R85, R83, R84, R28, capacitor C80, adjustable voltage regulator U5, and optocoupler U9. The anodes of diodes D5 and D6 are electrically connected to the first and second input terminals of the rectifier bridge in the input rectifier module 1, respectively. The cathodes of diodes D5 and D6 are both electrically connected to one end of resistor R80. The other end is connected in series with resistors R81 and R28, and then electrically connected to one end of resistor R82; one end of resistor R82 and one end of capacitor C80 are both electrically connected to the reference terminal of adjustable voltage regulator U5. The anode of adjustable voltage regulator U5, the other end of resistor R82 and the other end of capacitor C80 are all connected to GND ground. The cathode of adjustable voltage regulator U5 is electrically connected to the cathode of optocoupler U9. The anode of optocoupler U9 is connected in series with resistor R85 and then connected to VDD power supply. Resistor R88 is connected in parallel between the anode and cathode of optocoupler U9.

[0060] The collector of optocoupler U9 is connected to a 3V3 power supply. The emitter of optocoupler U9 and one end of resistor R83 are electrically connected to one end of resistor R84. The other end of resistor R83 is connected to the SGND ground terminal. One end of resistor R84 is electrically connected to microcontroller 5.

[0061] In this embodiment, as Figure 5As shown, the first detection module 6 uses an optocoupler U9 for high and low voltage isolation, ensuring that the microcontroller 5 is not affected by the detection end. The shaping, filtering, and voltage regulation circuits on the left side of the optocoupler U9 collect the AC power information, which is then transmitted to the microcontroller 5 for reading via the optocoupler. Simultaneously, an adjustable voltage regulator U5 replaces the functions of the Zener diode and transistor, further reducing the size of the switching power supply.

[0062] Furthermore, the second detection module 7 includes resistors R64 and R66 and capacitor C27; the output terminal of the secondary side filter module 3 is electrically connected to one end of resistor R64, and the other end of resistor R64, one end of resistor R66, and one end of capacitor C27 are all electrically connected to microcontroller 5, and the other end of resistor R66 and the other end of capacitor C27 are both connected to SGND ground.

[0063] In this embodiment, as Figure 6 As shown, the output terminal (VBUS) of the secondary filter module 3 is connected to a voltage divider circuit composed of resistors R64 and R66 to collect its output voltage and transmit it to the microcontroller 5 for reading.

[0064] Other configurations and operations of a primary-side feedback switching power supply according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0065] In the description of this specification, references to terms such as "embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A primary-side feedback switching power supply, characterized in that: The system includes an input rectifier module, a high power factor constant voltage drive module, a transformer T1, a secondary-side filter module, a constant current dimming module with protection, and a microcontroller. The input rectifier module, the high power factor constant voltage drive module, and the primary winding of the transformer T1 are sequentially electrically connected. The high power factor constant voltage drive module is also electrically connected to the primary auxiliary winding of the transformer T1, and receives voltage feedback from the primary auxiliary winding of the transformer T1. The secondary winding of the transformer T1, the secondary-side filter module, and the constant current dimming module with protection are sequentially electrically connected. The constant current dimming module with protection is also electrically connected to the microcontroller, and receives dimming signals from the microcontroller. The high power factor constant voltage drive module is equipped with a gallium nitride MOSFET Q1; the high power factor constant voltage drive module drives the gallium nitride MOSFET Q1 to achieve constant voltage output; The protected constant current dimming module consists of a chip with protection function and its peripheral circuits.

2. The primary-side feedback switching power supply according to claim 1, characterized in that: It also includes a first detection module and a second detection module; the first detection module is electrically connected between the secondary-side filter module and the microcontroller, and is used to feed back the voltage signal of the secondary-side filter module to the microcontroller; The second detection module is electrically connected between the input rectifier module and the microcontroller, and is used to feed back the voltage signal of the input rectifier module to the microcontroller.

3. The primary-side feedback switching power supply according to claim 1, characterized in that: The high power factor constant voltage drive module also includes resistors R14, R17, R19, and R36, MOSFET Q2, capacitor C11, diode D1, capacitor C2, capacitor C4, capacitor C9, high power factor drive chip U3, RCD snubber circuit, power supply circuit, voltage detection circuit, and first drive and current detection circuit; the output terminal of the input rectifier module is electrically connected to the same-name terminal of the primary winding of the transformer T1, and the RCD snubber circuit is connected in parallel between the same-name terminal and the opposite-name terminal of the primary winding of the transformer T1; The output terminal of the input rectifier module is connected to the gate of the MOSFET Q2 after being connected in series with resistors R14 and R17. The output terminal of the input rectifier module is connected to the drain of the MOSFET Q2 after being connected in series with resistors R36 and R19. The gate of the MOSFET Q2 is connected to the VIN terminal of the high power factor driver chip U3. The capacitor C11 is connected in parallel between the gate of the MOSFET Q2 and the GND terminal. The source of the MOSFET Q2 is connected to the anode of the diode D1. The VCC terminal of the high power factor driver chip U3 is connected to the cathode of the diode D1. The capacitor C2 is connected in parallel between the VCC terminal and the GND terminal of the high power factor driver chip U3. The capacitor C4 is connected in parallel between the VDD terminal and the GND terminal of the high power factor driver chip U3. The GND terminal of the high power factor driver chip U3 is connected to the GND terminal. The opposite-named end of the primary auxiliary winding of the transformer T1 is connected to the GND ground terminal, and the same-named end of the primary auxiliary winding of the transformer T1 is electrically connected to the VCC terminal of the high power factor drive chip U3 through the power supply circuit (22). The VSNS terminal of the high power factor drive chip U3 is electrically connected to the same-name terminal of the primary auxiliary winding of the transformer T1 via the voltage detection circuit. The opposite terminal of the primary winding of the transformer T1 is electrically connected to the drain of the gallium nitride MOS transistor Q1. The capacitor C9 is connected in parallel between the drain and source of the gallium nitride MOS transistor Q1. The OUT terminal and ISNS terminal of the high power factor driver chip U3 are electrically connected to the drive terminal and feedback terminal of the first drive and current detection circuit, respectively. The output terminal and input terminal of the first drive and current detection circuit are electrically connected to the gate and source of the gallium nitride MOS transistor Q1, respectively.

4. A primary-side feedback switching power supply according to claim 3, characterized in that: The first driving and current detection circuit includes resistors R2 and R5, diode D9, resistors R6 and R7, capacitor C6, resistor R49, resistor R50, resistor R3, resistor R4, resistor R16, and capacitor C7. The cathode of diode D9 and one end of resistor R5 are electrically connected to the OUT terminal of the high power factor driving chip U3. The anode of diode D9 is electrically connected to one end of resistor R2. The other ends of resistors R5, R2, R6, and R7 are all electrically connected to the gate of the gallium nitride MOSFET Q1. The other end of resistor R7... One end of the capacitor C6 is electrically connected to the source of the gallium nitride MOS transistor Q1. The other end of the capacitor C6, the other end of the resistor R6, one end of the resistor R49, one end of the resistor R50, one end of the resistor R3, one end of the resistor R4, and one end of the resistor R16 are all electrically connected to the source of the gallium nitride MOS transistor Q1. The other end of the resistor R16 and one end of the capacitor C7 are all electrically connected to the ISNS terminal of the high power factor driver chip U3. The other ends of the resistor R49, the other ends of the resistor R50, the other ends of the resistor R3, the other ends of the resistor R4, and the other ends of the capacitor C7 are all connected to the GND ground terminal.

5. A primary-side feedback switching power supply according to claim 3, characterized in that: The voltage detection circuit includes resistors R15, R21, and R22, diode D10, and capacitor C12. The primary auxiliary winding of transformer T1 is electrically connected to one end of resistor R21. The other end of resistor R21 and one end of resistor R22 are both electrically connected to the cathode of diode D10. The other end of resistor R22, one end of resistor R15, and one end of capacitor C12 are all electrically connected to the VSNS terminal of high power factor drive chip U3. The anode of diode D10, the other end of resistor R15, and the other end of capacitor C12 are all connected to ground (GND).

6. A primary-side feedback switching power supply according to claim 3, characterized in that: The power supply circuit includes a resistor R79, a diode D2, and a capacitor EC1. The primary auxiliary winding of the transformer T1 is electrically connected to the anode of the diode D2. The cathode of the diode D2 is connected in series with the resistor R79 and then electrically connected to the VCC terminal of the high power factor drive chip U3 and the positive terminal of the capacitor EC1. The negative terminal of the capacitor EC1 is connected to the GND ground terminal.

7. A primary-side feedback switching power supply according to claim 1, characterized in that: The protected constant current dimming module includes a resistor R42, a MOSFET Q4, a protected constant current dimming chip U4, a constant current output circuit, and a second drive and current detection circuit. The output terminal of the secondary-side filter module is electrically connected to the input terminal of the constant current output circuit. The output terminal of the secondary-side filter module is also connected in series with the resistor R42 and then electrically connected to the VIN terminal of the protected constant current dimming chip U4. The OUT terminal and ISNS terminal of the protected constant current dimming chip U4 are respectively electrically connected to the drive terminal and feedback terminal of the second drive and current detection circuit. The output terminal and input terminal of the second drive and current detection circuit are respectively electrically connected to the gate and source of the MOSFET Q4. The drain of the MOSFET Q4 is electrically connected to the input terminal of the inductor in the constant current output circuit (41). The RX terminal and TX terminal of the protected constant current dimming chip U4 are both electrically connected to the microcontroller.

8. A primary-side feedback switching power supply according to claim 2, characterized in that: The first detection module includes diodes D5 and D6, resistors R80, R81, R82, R88, R85, R83, R84, R28, capacitor C80, adjustable voltage regulator U5, and optocoupler U9. The anodes of diodes D5 and D6 are electrically connected to the first and second input terminals of the rectifier bridge in the input rectifier module, respectively. The cathodes of diodes D5 and D6 are both electrically connected to one end of resistor R80, and the other end of resistor R80 is connected in series with... After resistor R81 and resistor R28, one end of resistor R82 is electrically connected; one end of resistor R82 and one end of capacitor C80 are both electrically connected to the reference terminal of adjustable voltage regulator U5; the anode of adjustable voltage regulator U5, the other end of resistor R82 and the other end of capacitor C80 are all connected to GND ground; the cathode of adjustable voltage regulator U5 and the cathode of optocoupler U9 are electrically connected; the anode of optocoupler U9 is connected in series with resistor R85 and then connected to VDD power supply; resistor R88 is connected in parallel between the anode and cathode of optocoupler U9. The collector of the optocoupler U9 is connected to a 3V3 power supply. The emitter of the optocoupler U9 and one end of the resistor R83 are electrically connected to one end of the resistor R84. The other end of the resistor R83 is connected to the SGND ground terminal. One end of the resistor R84 is electrically connected to the microcontroller.

9. A primary-side feedback switching power supply according to claim 2, characterized in that: The second detection module includes resistor R64, resistor R66, and capacitor C27; the output terminal of the secondary side filter module is electrically connected to one end of resistor R64, the other end of resistor R64, one end of resistor R66, and one end of capacitor C27 are all electrically connected to the microcontroller, and the other end of resistor R66 and the other end of capacitor C27 are both connected to the SGND ground terminal.

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