Auxiliary power supply circuit and power supply circuit

Abstract

The utility model relates to the technical field of power supply, in particular to an auxiliary power supply circuit and a power supply circuit, which comprise a first current limiting unit, a second current limiting unit, a voltage-regulator tube ZD1, a diode D1 and an electrolytic capacitor E1. When the internal voltage of the switching power supply chip reaches a chip starting threshold value, a chip control circuit in the switching power supply chip starts to work, and meanwhile, the bus voltage is limited by a second current limiting unit, passes through a voltage-regulator tube ZD1 and then is filtered by an electrolytic capacitor E1, so that the power supply voltage of the high-voltage input end of the switching power supply chip is stabilized at 47V; therefore, the loss of the switching power supply chip is greatly reduced, the performance of the switching power supply chip is improved, and the design requirement is met.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply, in particular to an auxiliary power supply circuit and a power supply circuit. Background Art

[0002] For the power supply of the boost circuit, the existing high-voltage input power supply method of the switching power supply chip is to take power from the output voltage end of the Boost boost module to the high-voltage input end of the switching power supply chip. This power supply method has a big disadvantage: when the power supply is working at 230V, since it is taken from the 400V high voltage after the boost, the chip loss is very large when the power supply is working, and the temperature is very high, resulting in reduced working performance of the switching power supply chip and failure to meet the design requirements. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide an auxiliary power supply circuit and a power supply circuit, which can reduce the loss of the switching power supply chip, thereby improving the performance of the switching power supply chip and further meeting the design requirements.

[0004] In order to solve the above technical problems, a technical solution adopted by the utility model is:

[0005] An auxiliary power supply circuit includes a first current limiting unit, a second current limiting unit, a voltage regulator tube ZD1, a diode D1 and an electrolytic capacitor E1, wherein one end of the first current limiting unit is electrically connected to the cathode of the diode D1 and the high-voltage input end of an external switching power supply chip, respectively, the other end of the first current limiting unit is electrically connected to one end of the second current limiting unit and an external DC bus, the other end of the second current limiting unit is electrically connected to the anode of the diode D1, the cathode of the voltage regulator tube ZD1 and one end of the electrolytic capacitor E1, the anode of the voltage regulator tube ZD1 is electrically connected to the other end of the electrolytic capacitor E1, and the anode of the voltage regulator tube ZD1 and the other end of the electrolytic capacitor E1 are both grounded.

[0006] Furthermore, the first current limiting unit includes a resistor R4 and a resistor R5, one end of the resistor R5 is electrically connected to the cathode of the diode D1 and the high voltage input end of the external switching power supply chip, respectively, the other end of the resistor R5 is electrically connected to one end of the resistor R4, and the other end of the resistor R4 is electrically connected to one end of the second current limiting unit and the DC bus of the external device, respectively.

[0007] Furthermore, the second current limiting unit includes a resistor R6, a resistor R7 and a resistor R8, one end of the resistor R6 is electrically connected to the other end of the first current limiting unit and the DC bus of the external device, the other end of the resistor R6 is electrically connected to one end of the resistor R7, the other end of the resistor R7 is electrically connected to one end of the resistor R8, and the other end of the resistor R8 is electrically connected to the cathode of the Zener diode ZD1, the anode of the diode D1 and one end of the electrolytic capacitor E1.

[0008] Another technical solution adopted by the utility model is:

[0009] A power supply circuit comprises a Boost boost module, a switching power supply chip and the above-mentioned auxiliary power supply circuit, wherein the Boost boost module is electrically connected to the gate terminal of the switching power supply chip, a first current limiting unit in the auxiliary power supply circuit and a second current limiting unit in the auxiliary power supply circuit respectively.

[0010] The Boost module includes an inductor L2, a diode D3, a resistor B1, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a capacitor C4 and an electrolytic capacitor E2. One end of the inductor L2 is electrically connected to the other end of the first current limiting unit, one end of the second current limiting unit and the DC bus of the peripheral device, the other end of the inductor L2 is electrically connected to the anode of the diode D3 and one end of the resistor B1, the other end of the resistor B1 is electrically connected to the gate end of the switching power supply chip, and the cathode of the diode D3 is electrically connected to the gate end of the switching power supply chip. The first and second ends of the resistor R11 and the second end of the capacitor C4 are electrically connected to one end of the resistor R9 and one end of the electrolytic capacitor E2, respectively. The other end of the resistor R9 is electrically connected to one end of the resistor R10, the other end of the resistor R10 is electrically connected to one end of the resistor R11, the other end of the resistor R11 is electrically connected to one end of the resistor R12, one end of the capacitor C4 and the overvoltage protection end of the switching power supply chip, the other end of the resistor R12 is electrically connected to the other end of the capacitor C4, and the other end of the resistor R12 and the other end of the capacitor C4 are both grounded, and the other end of the electrolytic capacitor E2 is grounded.

[0011] Furthermore, the Boost module also includes a resistor R2 and a resistor R3, one end of the resistor R2 is electrically connected to one end of the resistor R3 and the current detection end of the switching power supply chip respectively, the other end of the resistor R2 is electrically connected to the other end of the resistor R3, and the other end of the resistor R2 and the other end of the resistor R3 are both grounded.

[0012] Furthermore, the Boost module also includes a resistor R13, a resistor R14 and a thermistor NTC1, one end of the thermistor NTC1 is electrically connected to one end of the resistor R14, the other end of the resistor R14 is electrically connected to one end of the resistor R13 and the threshold end of the switching power supply chip respectively, the other end of the thermistor NTC1 is electrically connected to the other end of the resistor R13, and the other end of the thermistor NTC1 and the other end of the resistor R13 are both grounded.

[0013] Furthermore, the Boost module also includes a resistor R16 and a capacitor C5, one end of the resistor R16 is electrically connected to the other end of the inductor L2, one end of the resistor B1 and the anode of the diode D3, the other end of the resistor R16 is electrically connected to one end of the capacitor C5, and the other end of the capacitor C5 is electrically connected to the cathode of the diode D3, one end of the resistor R9 and one end of the electrolytic capacitor E2.

[0014] Furthermore, it also includes an input rectification and filtering module, which is electrically connected to the first current limiting unit in the auxiliary power supply circuit, the second current limiting unit in the auxiliary power supply circuit, and the Boost boost module respectively.

[0015] Furthermore, it also includes an EMI filter module, and the input rectification and filtering module is electrically connected to the first current limiting unit in the auxiliary power supply circuit, the second current limiting unit in the auxiliary power supply circuit and the Boost boost module through the EMI filter module.

[0016] The beneficial effects of the utility model are:

[0017] This solution sets up an auxiliary power supply circuit, which includes a first current limiting unit, a second current limiting unit, a voltage regulator ZD1, a diode D1 and an electrolytic capacitor E1. After the system is powered on, the bus voltage supplies power to the switching power supply chip through the first current limiting unit. When the internal voltage of the switching power supply chip reaches the chip start-up threshold, the chip control circuit inside the switching power supply chip starts to work. At the same time, the bus voltage is limited by the second current limiting unit, passes through the voltage regulator ZD1, and then is filtered by the electrolytic capacitor E1 to stabilize the power supply voltage at the high-voltage input end of the switching power supply chip at 47V. This greatly reduces the loss of the switching power supply chip, improves the performance of the switching power supply chip, and meets the design requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a circuit schematic diagram of the auxiliary power supply circuit of the utility model;

[0019] Figure 2 It is a circuit schematic diagram of the power supply circuit of the utility model;

[0020] Description of labels:

[0021] 1. Boost module; 2. Input rectifier filter module; 3. EMI filter module. DETAILED DESCRIPTION

[0022] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes and the accompanying drawings.

[0023] Please refer to Figure 1 , the first technical solution adopted by the utility model is:

[0024] An auxiliary power supply circuit includes a first current limiting unit, a second current limiting unit, a voltage regulator tube ZD1, a diode D1 and an electrolytic capacitor E1, wherein one end of the first current limiting unit is electrically connected to the cathode of the diode D1 and the high-voltage input end of an external switching power supply chip, respectively, the other end of the first current limiting unit is electrically connected to one end of the second current limiting unit and an external DC bus, the other end of the second current limiting unit is electrically connected to the anode of the diode D1, the cathode of the voltage regulator tube ZD1 and one end of the electrolytic capacitor E1, the anode of the voltage regulator tube ZD1 is electrically connected to the other end of the electrolytic capacitor E1, and the anode of the voltage regulator tube ZD1 and the other end of the electrolytic capacitor E1 are both grounded.

[0025] From the above description, it can be seen that the beneficial effects of the utility model are:

[0026] This solution sets up an auxiliary power supply circuit, which includes a first current limiting unit, a second current limiting unit, a voltage regulator ZD1, a diode D1 and an electrolytic capacitor E1. After the system is powered on, the bus voltage supplies power to the switching power supply chip through the first current limiting unit. When the internal voltage of the switching power supply chip reaches the chip start-up threshold, the chip control circuit inside the switching power supply chip starts to work. At the same time, the bus voltage is limited by the second current limiting unit, passes through the voltage regulator ZD1, and then is filtered by the electrolytic capacitor E1 to stabilize the power supply voltage at the high-voltage input end of the switching power supply chip at 47V. This greatly reduces the loss of the switching power supply chip, improves the performance of the switching power supply chip, and meets the design requirements.

[0027] Furthermore, the first current limiting unit includes a resistor R4 and a resistor R5, one end of the resistor R5 is electrically connected to the cathode of the diode D1 and the high voltage input end of the external switching power supply chip, respectively, the other end of the resistor R5 is electrically connected to one end of the resistor R4, and the other end of the resistor R4 is electrically connected to one end of the second current limiting unit and the DC bus of the external device, respectively.

[0028] It can be seen from the above description that the resistors R4 and R5 play a role in current limiting.

[0029] Furthermore, the second current limiting unit includes a resistor R6, a resistor R7 and a resistor R8, one end of the resistor R6 is electrically connected to the other end of the first current limiting unit and the DC bus of the external device, the other end of the resistor R6 is electrically connected to one end of the resistor R7, the other end of the resistor R7 is electrically connected to one end of the resistor R8, and the other end of the resistor R8 is electrically connected to the cathode of the Zener diode ZD1, the anode of the diode D1 and one end of the electrolytic capacitor E1.

[0030] It can be seen from the above description that the resistors R6, R7 and R8 play a role in current limiting.

[0031] Please refer to Figure 2 , the second technical solution adopted by the utility model is:

[0032] A power supply circuit comprises a Boost boost module, a switching power supply chip and the above-mentioned auxiliary power supply circuit, wherein the Boost boost module is electrically connected to the gate terminal of the switching power supply chip, a first current limiting unit in the auxiliary power supply circuit and a second current limiting unit in the auxiliary power supply circuit respectively.

[0033] From the above description, it can be seen that the beneficial effects of the utility model are:

[0034] This solution sets up an auxiliary power supply circuit so that the high-voltage input end of the switching power supply chip does not draw power from the output voltage of the Boost module. This can reduce chip losses, lower chip temperature, improve product performance, and meet design requirements.

[0035] The Boost module includes an inductor L2, a diode D3, a resistor B1, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a capacitor C4 and an electrolytic capacitor E2. One end of the inductor L2 is electrically connected to the other end of the first current limiting unit, one end of the second current limiting unit and the DC bus of the peripheral device, the other end of the inductor L2 is electrically connected to the anode of the diode D3 and one end of the resistor B1, the other end of the resistor B1 is electrically connected to the gate end of the switching power supply chip, and the cathode of the diode D3 is electrically connected to the gate end of the switching power supply chip. The first and second ends of the resistor R11 and the second end of the capacitor C4 are electrically connected to one end of the resistor R9 and one end of the electrolytic capacitor E2, respectively. The other end of the resistor R9 is electrically connected to one end of the resistor R10, the other end of the resistor R10 is electrically connected to one end of the resistor R11, the other end of the resistor R11 is electrically connected to one end of the resistor R12, one end of the capacitor C4 and the overvoltage protection end of the switching power supply chip, the other end of the resistor R12 is electrically connected to the other end of the capacitor C4, and the other end of the resistor R12 and the other end of the capacitor C4 are both grounded, and the other end of the electrolytic capacitor E2 is grounded.

[0036] Furthermore, the Boost module also includes a resistor R2 and a resistor R3, one end of the resistor R2 is electrically connected to one end of the resistor R3 and the current detection end of the switching power supply chip respectively, the other end of the resistor R2 is electrically connected to the other end of the resistor R3, and the other end of the resistor R2 and the other end of the resistor R3 are both grounded.

[0037] Furthermore, the Boost module also includes a resistor R13, a resistor R14 and a thermistor NTC1, one end of the thermistor NTC1 is electrically connected to one end of the resistor R14, the other end of the resistor R14 is electrically connected to one end of the resistor R13 and the threshold end of the switching power supply chip respectively, the other end of the thermistor NTC1 is electrically connected to the other end of the resistor R13, and the other end of the thermistor NTC1 and the other end of the resistor R13 are both grounded.

[0038] Furthermore, the Boost module also includes a resistor R16 and a capacitor C5, one end of the resistor R16 is electrically connected to the other end of the inductor L2, one end of the resistor B1 and the anode of the diode D3, the other end of the resistor R16 is electrically connected to one end of the capacitor C5, and the other end of the capacitor C5 is electrically connected to the cathode of the diode D3, one end of the resistor R9 and one end of the electrolytic capacitor E2.

[0039] Furthermore, it also includes an input rectification and filtering module, which is electrically connected to the first current limiting unit in the auxiliary power supply circuit, the second current limiting unit in the auxiliary power supply circuit, and the Boost boost module respectively.

[0040] Furthermore, it also includes an EMI filter module, and the input rectification and filtering module is electrically connected to the first current limiting unit in the auxiliary power supply circuit, the second current limiting unit in the auxiliary power supply circuit and the Boost boost module through the EMI filter module.

[0041] Please refer to Figure 1 and Figure 2 As shown, the first embodiment of the utility model is:

[0042] Please refer to Figure 1 and Figure 2 An auxiliary power supply circuit includes a first current limiting unit, a second current limiting unit, a voltage regulator ZD1 (voltage regulator value is 47V), a diode D1 (model ESIJ) and an electrolytic capacitor E1 (capacitance value is 1μF), one end of the first current limiting unit is respectively connected to the cathode of the diode D1 and the external switching power supply chip (i.e. Figure 2The chip IC1 (model BP2616C) in the figure, the switching power supply chips appearing below all refer to the chip IC1) is electrically connected to the high-voltage input end, the other end of the first current limiting unit is respectively electrically connected to one end of the second current limiting unit and the DC bus of the external device, the other end of the second current limiting unit is respectively electrically connected to the anode of the diode D1, the cathode of the voltage-stabilizing tube ZD1 and one end of the electrolytic capacitor E1, the anode of the voltage-stabilizing tube ZD1 is electrically connected to the other end of the electrolytic capacitor E1, and the anode of the voltage-stabilizing tube ZD1 and the other end of the electrolytic capacitor E1 are both grounded.

[0043] Please refer to Figure 1 The first current limiting unit includes a resistor R4 (resistance value is 22kΩ) and a resistor R5 (resistance value is 22kΩ), one end of the resistor R5 is electrically connected to the cathode of the diode D1 and the high voltage input end of the external switching power supply chip, the other end of the resistor R5 is electrically connected to one end of the resistor R4, and the other end of the resistor R4 is electrically connected to one end of the second current limiting unit and the external DC bus.

[0044] Please refer to Figure 1 The second current limiting unit includes a resistor R6 (resistance value is 100kΩ), a resistor R7 (resistance value is 100kΩ) and a resistor R8 (resistance value is 100kΩ), one end of the resistor R6 is electrically connected to the other end of the first current limiting unit and the DC bus of the external device, the other end of the resistor R6 is electrically connected to one end of the resistor R7, the other end of the resistor R7 is electrically connected to one end of the resistor R8, and the other end of the resistor R8 is electrically connected to the cathode of the voltage regulator tube ZD1, the anode of the diode D1 and one end of the electrolytic capacitor E1.

[0045] The working principle of the auxiliary power supply circuit mentioned above is:

[0046] VBUS is the bus voltage after rectification. After the system is powered on, the bus voltage supplies power to the switching power supply chip through resistors R4 and R5. When the internal voltage of the switching power supply chip reaches the chip start-up threshold, the chip control circuit starts to work. At the same time, the bus voltage is limited by resistors R6, R7 and R8, and then filtered by the voltage regulator ZD1 and the electrolytic capacitor E1 to stabilize the power supply voltage at the high-voltage input end of the switching power supply chip at 47V (the maintenance power supply of the high-voltage input end of the switching power supply chip must be greater than 30V. The voltage regulator value of the voltage regulator ZD1 is different, and the obtained power supply voltage is also different. In this scheme, a voltage regulator ZD1 with a voltage regulation value greater than 30V is used; the greater the chip power supply current, the greater the chip loss, and the chip power supply current is proportional to the supply voltage, the higher the supply voltage, the greater the chip power supply current, the greater the loss, the lower the supply voltage, the smaller the chip power supply current, so the chip loss is lower; this scheme sets an auxiliary power supply circuit so that the high-voltage input end of the switching power supply chip does not draw power from the output voltage of the Boost boost module, thereby reducing the chip loss, lowering the chip temperature, improving the product performance, and meeting the design requirements.

[0047] Please refer to Figure 2 , Embodiment 2 of the present utility model is:

[0048] A power supply circuit comprises a Boost module 1, a switching power supply chip and the auxiliary power supply circuit of embodiment 1, wherein the Boost module 1 is electrically connected to the gate terminal of the switching power supply chip, the first current limiting unit in the auxiliary power supply circuit and the second current limiting unit in the auxiliary power supply circuit respectively.

[0049] The Boost module 1 includes an inductor L2 (with an inductance of 3.3 mH), a diode D3 (model ES1J), a resistor B1 (with a resistance of 600 Ω), a resistor R9 (with a resistance of 300 kΩ), a resistor R10 (with a resistance of 300 kΩ), a resistor R11 (with a resistance of 300 kΩ), a resistor R12 (with a resistance of 1 kΩ), a capacitor C4 (with a capacitance of 47 pF) and an electrolytic capacitor E2 (with a capacitance of 15 μF), one end of the inductor L2 is electrically connected to the other end of the first current limiting unit, one end of the second current limiting unit and the DC bus of the peripheral device, and the other end of the inductor L2 is electrically connected to the anode and the cathode of the diode D3, respectively. One end of the resistor B1 is electrically connected, the other end of the resistor B1 is electrically connected to the gate end of the switching power supply chip, the cathode of the diode D3 is electrically connected to one end of the resistor R9 and one end of the electrolytic capacitor E2 respectively, the other end of the resistor R9 is electrically connected to one end of the resistor R10, the other end of the resistor R10 is electrically connected to one end of the resistor R11, the other end of the resistor R11 is electrically connected to one end of the resistor R12, one end of the capacitor C4 and the overvoltage protection end of the switching power supply chip respectively, the other end of the resistor R12 is electrically connected to the other end of the capacitor C4 and the other end of the resistor R12 and the other end of the capacitor C4 are both grounded, and the other end of the electrolytic capacitor E2 is grounded.

[0050] The Boost module 1 also includes a resistor R2 (resistance value is 6.8Ω) and a resistor R3 (resistance value is 6.8Ω), one end of the resistor R2 is electrically connected to one end of the resistor R3 and the current detection end of the switching power supply chip respectively, the other end of the resistor R2 is electrically connected to the other end of the resistor R3, and the other end of the resistor R2 and the other end of the resistor R3 are both grounded, and the resistor R2 and the resistor R3 are both sampling resistors for setting the output current.

[0051] The Boost module 1 also includes a resistor R13 (resistance value is 150kΩ), a resistor R14 (resistance value is 4.7kΩ) and a thermistor NTC1 (resistance value is 100kΩ), one end of the thermistor NTC1 is electrically connected to one end of the resistor R14, the other end of the resistor R14 is electrically connected to one end of the resistor R13 and the threshold end of the switching power supply chip respectively, the other end of the thermistor NTC1 is electrically connected to the other end of the resistor R13, and the other end of the thermistor NTC1 and the other end of the resistor R13 are both grounded; the resistor R13 is used to set the over-temperature point of the switching power supply chip, the resistor R14 is connected in series with the thermistor NTC1, and is used to set the over-temperature current drop point; the thermistor NTC1 is used to detect the over-temperature current drop.

[0052] The Boost module 1 also includes a resistor R16 (resistance value is 20Ω) and a capacitor C5 (capacitance value is 100pF), one end of the resistor R16 is electrically connected to the other end of the inductor L2, one end of the resistor B1 and the anode of the diode D3, the other end of the resistor R16 is electrically connected to one end of the capacitor C5, and the other end of the capacitor C5 is electrically connected to the cathode of the diode D3, one end of the resistor R9 and one end of the electrolytic capacitor E2; the resistor R16 and the capacitor C5 form an RC oscillation circuit for anti-EMI interference.

[0053] The Boost module 1 also includes a capacitor C3 (capacitance value is 2.2nF) and a diode D2 (model M7). For the specific connection relationship between the components, please refer to Figure 2 , diode D2 is used to protect the power-on moment, inductor L2 is not saturated; capacitor C3 is used to resist EMI interference;

[0054] It also includes an input rectifier filter module 2, which is electrically connected to the first current limiting unit in the auxiliary power supply circuit, the second current limiting unit in the auxiliary power supply circuit, and the Boost boost module 1. The input rectifier filter module 2 includes a resistor F1 (resistance value is 10Ω), a varistor RV1, a safety capacitor CX1 (capacitance value is 100nF) and a rectifier bridge BR1 (model MB10FU). Please refer to the specific connection relationship between the components. Figure 2 The alternating current is rectified into direct current through resistor F1, varistor RV1, safety capacitor CX1 and rectifier bridge BR1. F1 acts as a fuse resistor, varistor RV1 acts as a surge protector, and safety capacitor CX1 acts as a filter.

[0055] It also includes an EMI filter module 3, and the input rectifier filter module 2 is electrically connected to the first current limiting unit in the auxiliary power supply circuit, the second current limiting unit in the auxiliary power supply circuit, and the Boost boost module 1 through the EMI filter module 3. The EMI filter module 3 includes an inductor L1 (inductance value is 2mH), a resistor R1 (resistance value is 5.1kΩ), a capacitor C1 (capacitance value is 100nF) and a capacitor C2 (capacitance value is 100nF). For the specific connection relationship between the components, please refer to Figure 2 The functions of capacitors C1, C2 and inductor L1 are all filtering, and resistor R1 plays a current limiting role.

[0056] The working principle of the above power supply circuit is:

[0057] The Boost boost module 1 converts a low-voltage DC power supply into a high voltage. When the switch tube inside the switching power supply chip is turned on, the current of the inductor L1 increases and stores energy at the same time. At this time, the diode D3 is turned off, and the current on the inductor directly charges E2 and discharges the load. When the switch tube inside the switching power supply chip is turned off, the energy stored on the inductor L2 will be discharged to the load through the diode D3. The inductor L2 is a boost inductor and its function is to store energy. The electrolytic capacitor E2 is an output filter capacitor. The resistor R2 and the resistor R3 are both sampling resistors. The diode D3 is an output freewheeling diode. The resistor R13 is a maximum on-time setting resistor. The resistors R9, R10 and R11 are pull-up resistors at the overvoltage protection end of the switching power supply chip. The resistor R12 is a pull-down resistor at the overvoltage protection end of the switching power supply chip. The capacitor C4 is a filter capacitor to prevent the overvoltage protection end of the switching power supply chip from being interfered with.

[0058] In summary, the utility model provides an auxiliary power supply circuit and a power supply circuit. An auxiliary power supply circuit is set up. The auxiliary power supply circuit includes a first current limiting unit, a second current limiting unit, a voltage regulator ZD1, a diode D1 and an electrolytic capacitor E1. After the system is powered on, the bus voltage supplies power to the switching power supply chip through the first current limiting unit. When the internal voltage of the switching power supply chip reaches the chip start-up threshold, the chip control circuit inside the switching power supply chip starts to work. At the same time, the bus voltage is limited by the second current limiting unit, passes through the voltage regulator ZD1, and then is filtered by the electrolytic capacitor E1, so that the power supply voltage at the high-voltage input end of the switching power supply chip is stabilized at 47V, and the high-voltage input end of the switching power supply chip does not take power from the output voltage of the Boost boost module, thereby greatly reducing the loss of the switching power supply chip, improving the performance of the switching power supply chip, and meeting the design requirements.

[0059] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. An auxiliary power supply circuit, characterized in that: It includes a first current limiting unit, a second current limiting unit, a voltage regulator ZD1, a diode D1 and an electrolytic capacitor E1, one end of the first current limiting unit is electrically connected to the cathode of the diode D1 and the high-voltage input end of the external switching power supply chip, the other end of the first current limiting unit is electrically connected to one end of the second current limiting unit and the external DC bus, the other end of the second current limiting unit is electrically connected to the anode of the diode D1, the cathode of the voltage regulator ZD1 and one end of the electrolytic capacitor E1, the anode of the voltage regulator ZD1 is electrically connected to the other end of the electrolytic capacitor E1, and the anode of the voltage regulator ZD1 and the other end of the electrolytic capacitor E1 are both grounded.

2. The auxiliary power supply circuit according to claim 1, characterized in that: The first current limiting unit includes a resistor R4 and a resistor R5, one end of the resistor R5 is electrically connected to the cathode of the diode D1 and the high voltage input end of the external switching power supply chip, the other end of the resistor R5 is electrically connected to one end of the resistor R4, and the other end of the resistor R4 is electrically connected to one end of the second current limiting unit and the DC bus of the external device.

3. The auxiliary power supply circuit according to claim 1, characterized in that: The second current limiting unit includes a resistor R6, a resistor R7 and a resistor R8, one end of the resistor R6 is electrically connected to the other end of the first current limiting unit and the DC bus of the external device, the other end of the resistor R6 is electrically connected to one end of the resistor R7, the other end of the resistor R7 is electrically connected to one end of the resistor R8, and the other end of the resistor R8 is electrically connected to the cathode of the voltage regulator tube ZD1, the anode of the diode D1 and one end of the electrolytic capacitor E1.

4. A power supply circuit, characterized in that: It comprises a Boost module, a switching power supply chip and the auxiliary power supply circuit of any one of claims 1 to 3, wherein the Boost module is electrically connected to the gate terminal of the switching power supply chip, the first current limiting unit in the auxiliary power supply circuit and the second current limiting unit in the auxiliary power supply circuit respectively.

5. The power supply circuit according to claim 4, characterized in that: The Boost module includes an inductor L2, a diode D3, a resistor B1, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a capacitor C4 and an electrolytic capacitor E2. One end of the inductor L2 is electrically connected to the other end of the first current limiting unit, one end of the second current limiting unit and the DC bus of the peripheral device, the other end of the inductor L2 is electrically connected to the anode of the diode D3 and one end of the resistor B1, the other end of the resistor B1 is electrically connected to the gate end of the switching power supply chip, and the cathode of the diode D3 is electrically connected to the gate end of the switching power supply chip. The first and second ends of the resistor R11 and the second end of the capacitor C4 are electrically connected to one end of the resistor R9 and one end of the electrolytic capacitor E2, respectively. The other end of the resistor R9 is electrically connected to one end of the resistor R10, the other end of the resistor R10 is electrically connected to one end of the resistor R11, the other end of the resistor R11 is electrically connected to one end of the resistor R12, one end of the capacitor C4 and the overvoltage protection end of the switching power supply chip, the other end of the resistor R12 is electrically connected to the other end of the capacitor C4, and the other end of the resistor R12 and the other end of the capacitor C4 are both grounded, and the other end of the electrolytic capacitor E2 is grounded.

6. The power supply circuit according to claim 5, characterized in that: The Boost module also includes a resistor R2 and a resistor R3, one end of the resistor R2 is electrically connected to one end of the resistor R3 and the current detection end of the switching power supply chip respectively, the other end of the resistor R2 is electrically connected to the other end of the resistor R3, and the other end of the resistor R2 and the other end of the resistor R3 are both grounded.

7. The power supply circuit according to claim 5, characterized in that: The Boost module also includes a resistor R13, a resistor R14 and a thermistor NTC1, one end of the thermistor NTC1 is electrically connected to one end of the resistor R14, the other end of the resistor R14 is electrically connected to one end of the resistor R13 and the threshold end of the switching power supply chip respectively, the other end of the thermistor NTC1 is electrically connected to the other end of the resistor R13, and the other end of the thermistor NTC1 and the other end of the resistor R13 are both grounded.

8. The power supply circuit according to claim 5, characterized in that: The Boost module also includes a resistor R16 and a capacitor C5, one end of the resistor R16 is electrically connected to the other end of the inductor L2, one end of the resistor B1 and the anode of the diode D3, the other end of the resistor R16 is electrically connected to one end of the capacitor C5, and the other end of the capacitor C5 is electrically connected to the cathode of the diode D3, one end of the resistor R9 and one end of the electrolytic capacitor E2.

9. The power supply circuit according to claim 4, characterized in that: It also includes an input rectification and filtering module, which is electrically connected to the first current limiting unit in the auxiliary power supply circuit, the second current limiting unit in the auxiliary power supply circuit, and the Boost boost module respectively.

10. The power supply circuit according to claim 9, characterized in that: It also includes an EMI filter module, and the input rectification and filtering module is electrically connected to the first current limiting unit in the auxiliary power supply circuit, the second current limiting unit in the auxiliary power supply circuit and the Boost boost module through the EMI filter module.

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