Short-circuit protection circuit of high-power brushless direct-current fan controller

Abstract

The utility model particularly relates to a short-circuit protection circuit of a high-power brushless direct-current fan controller, which comprises a delay soft start circuit, a current-limiting protection detection circuit and an overcurrent protection detection circuit which are all connected with a switching circuit. The overcurrent protection detection circuit is connected with the MCU main control circuit through an overcurrent feedback signal circuit and a fan restart signal circuit; according to the invention, time-delay soft start can be realized at the power-on moment of the controller, and two protection modes of current-limiting non-stop protection and over-current stop protection are provided at the same time; the problem of quick burning of a power tube caused by instantaneous and sudden increase of bus current when a high-power fan controller has bridge arm direct connection and inter-phase or relative ground short circuit is solved, and the response speed of short-circuit protection of the controller can be increased to a great extent.

Description

Technical Field

[0001] The utility model belongs to the technical field of high-power DC fan control, and in particular relates to a short-circuit protection circuit of a high-power brushless DC fan controller. Background Art

[0002] Since large industrial equipment will generate a lot of heat inside during power-on operation, fans are widely used in many fields as the best choice for air cooling. The reliability of the fan and its controller plays a vital role in the heat dissipation performance of high-power equipment. This requires that the fan controller should have a fast self-protection function when the fan has an abnormal state of instantaneous short circuit and overcurrent, especially when the fan winding is short-circuited between phases, short-circuited to the ground, or the controller power bridge arm is directly connected, so as to avoid the controller from burning due to instantaneous overcurrent and restart the fan in a short time. The traditional short-circuit protection methods of resistance sampling or current sensor sampling are to implement current sampling through hardware and transmit it to the MCU main control, and then perform software protection through the MCU main control. However, the response time of this short-circuit protection method is relatively long, at the millisecond level. When the fan and controller suddenly have an instantaneous short circuit fault, the current will increase rapidly within microseconds. At this time, the power tube will be broken down and burned by overcurrent before the software can provide protection. The protection is not played, causing destructive damage to the fan controller, and the fan cannot work normally, which seriously affects the heat dissipation of the equipment during operation and greatly increases the subsequent maintenance cost of the fan controller.

[0003] A Chinese patent with publication number CN110797837A discloses an overcurrent protection circuit, including: a bridge rectifier circuit, a motor load interface circuit, a MOS tube output and current sampling circuit, a sampling high-voltage isolation circuit, a MOS tube drive and protection circuit, an overcurrent protection comparison circuit, an MCU control circuit, an overcurrent protection reference circuit, an optocoupler isolation circuit I, an optocoupler isolation circuit II, and an optocoupler isolation circuit III; although the patent realizes overcurrent protection of power drive, the patent has the following defects: 1. The optocoupler isolation circuit I is the MCU that sends an overcurrent protection release signal to the positive input terminal of the operational amplifier in the overcurrent protection circuit after receiving the overcurrent signal. The overcurrent protection reference value is a voltage signal directly sent by the MCU. Once the MCU fails, the overcurrent protection reference value cannot be sent; 2. It is only applicable to single-phase DC motors and not to three-phase motors. Utility Model Content

[0004] In order to solve the above technical problems, the utility model provides a short-circuit protection circuit of a high-power brushless DC fan controller.

[0005] The utility model is realized through the following technical solutions.

[0006] A short-circuit protection circuit for a high-power brushless DC fan controller comprises a time-delay soft-start circuit, a current-limiting protection detection circuit and an overcurrent protection detection circuit. The time-delay soft-start circuit, the current-limiting protection detection circuit and the overcurrent protection detection circuit are all connected to a switch circuit. The overcurrent protection detection circuit is connected to an MCU main control circuit via an overcurrent feedback signal circuit and a fan restart signal circuit. The overcurrent protection detection circuit and the current-limiting protection detection circuit are also connected to a bus current terminal of a motor controller. The input terminal of the time-delay soft-start circuit is connected to a DC power supply input terminal. The output terminal of the switch circuit is connected to an enable port of a motor driver IC.

[0007] The delayed soft start circuit includes an inverter F1, a switching diode D4, a resistor R9, and a capacitor C4; the input end of the inverter F1 is connected to the anode of the diode D4, the resistor R9, and one end of the capacitor C4; the output end of the inverter F1 is connected to the switching diode D5, the switching diode D2, and the switching diode D3 in sequence, the power supply end is connected to the positive electrode of the 5V DC power supply, and the ground end is connected to the ground of the 5V DC power supply; the cathode of the switching diode D4 and the other end of the resistor R9 are both connected to the positive electrode of the 5V DC power supply; the other end of the capacitor C4 is connected to the ground of the 5V DC power supply.

[0008] The current limiting protection detection circuit includes an operational amplifier Y1A, a resistor R2, a resistor R3 and a capacitor C1; one end of the resistor R2 and the resistor R3 connected in parallel is connected to the inverting input end of the operational amplifier Y1A, the resistor R1 and one end of the capacitor C1, and the other end is connected to the other end of the capacitor C1 and then connected to the 5V DC power supply ground; the non-inverting input end of the operational amplifier Y1A is connected to one end of the resistor R6 and the resistor R8, the output end is connected to the other end of the resistor R8 and the anode of the switching diode D1, the power supply end is connected to the positive electrode of the 5V DC power supply, and the power supply ground is connected to the 5V DC power supply ground; the other end of the resistor R6 is connected to one end of the capacitor C3 and the resistor R5; the other end of the resistor R5 is connected to one end of the resistor R4 and the capacitor C2; the other ends of the capacitor C2 and the capacitor C3 are connected to the 5V DC power supply ground; the other end of the resistor R4 is connected to the bus current end of the motor controller; the other end of the resistor R1 is connected to the positive electrode of the 5V DC power supply.

[0009] The overcurrent protection detection circuit includes an operational amplifier Y1B, a resistor R11, a resistor R12, and a capacitor C5; one end of the resistor R11 and the resistor R12 connected in parallel is connected to the inverting input end of the operational amplifier Y1B, the capacitor C5, and one end of the resistor R10, and the other end is connected to the other end of the capacitor C5 and then connected to the ground of a 5V DC power supply; the non-inverting input end of the operational amplifier Y1B is connected to one end of the resistor R13 and the resistor R14, and the output end is connected to the anodes of the switching diode D6 and the switching diode D7; the other end of the resistor R14 is connected to the cathode of the switching diode D7; the other end of the resistor R13 is connected to the bus current end of the motor controller; the other end of the resistor R10 is connected to the positive electrode of the 5V DC power supply.

[0010] The fan restart signal circuit includes a photocoupler G1 and an NPN transistor Q2; pin 1 of the photocoupler G1 is connected to one end of a resistor R18, pin 2 is connected to a 3.3V DC power supply ground, pin 3 is connected to one end of a capacitor C6 and then to a 5V DC power supply ground, and pin 4 is connected to the other end of the capacitor C6, the resistor R16 and one end of the resistor R15; the other end of the resistor R15 is connected to the base of the NPN transistor Q2; the collector of the NPN transistor Q2 is connected to the non-inverting input end of the operational amplifier Y1B, the emitter is connected to the 5V DC power supply ground, and the other end of the resistor R16 is connected to the positive electrode of the 5V DC power supply.

[0011] The overcurrent feedback signal circuit includes a photocoupler G2, a resistor R17, and a capacitor C7; pin 1 of the photocoupler G2 is connected to the output end of the operational amplifier Y1B through a resistor R19, pin 2 is connected to the 5V DC power supply ground, pin 3 is connected to one end of the capacitor C7 and then to the 3.3V DC power supply ground, and pin 4 is connected to the other end of the capacitor C7 and one end of the resistor R17; the other end of the resistor R17 is connected to the positive electrode of the 3.3V DC power supply.

[0012] The MCU main control circuit includes an MCU main control chip U1, wherein the 6th pin, the 19th pin, the 27th pin and the 1st pin of the MCU main control chip U1 are connected to one end of the capacitor C22, the capacitor C23, the capacitor C24, the capacitor C25, the capacitor C26 and the capacitor C27 in parallel and then connected to the positive electrode of the 3.3V DC power supply, the 35th pin is connected to the 3.3V DC power supply ground through the resistor R22, the 4th pin is connected to one end of the resistor R23 and the capacitor C28, the 12th pin is connected to the 1st pin of the photoelectric coupler G1 through the resistor R18. The first embodiment of the present invention is connected to the optical coupler G2, the first pin 13 is connected to the first pin 4 of the optical coupler G2, the first pin 17 is connected to the 3.3V DC power supply ground through the resistor R24, the first pin 5, the first pin 36, the first pin 26 and the first pin 18 are all connected to the 3.3V DC power supply ground; the other end of the capacitor C22, the capacitor C23, the capacitor C24, the capacitor C25, the capacitor C26 and the capacitor C27 after being connected in parallel is connected to the 3.3V DC power supply ground; the other end of the resistor R23 is connected to the positive electrode of the 3.3V DC power supply, and the other end of the capacitor C28 is connected to the 3.3V DC power supply ground.

[0013] The switching circuit includes an NPN transistor Q1, a base of which is connected to the cathodes of the switching diode D3, the switching diode D1 and the switching diode D6, a collector is connected to the positive electrode of a 5V DC power supply, and an emitter is connected to an enable port of a motor driver IC through a resistor R7.

[0014] The beneficial effects of the utility model are:

[0015] 1. The short-circuit protection response speed of this circuit is extremely fast. When a short-circuit fault occurs, the controller's drive enable can be instantly turned off, which can protect the controller's power tube from being burned by instantaneous large current to a great extent, reduce the controller's after-sales maintenance cost, and at the same time, improve the controller's reliability;

[0016] 2. This circuit can make the controller have a power-on delay soft start function. The controller drive enable is immediately turned off at the moment of power-on to prevent the PWM wave emitted by the controller from being in an uncertain high or low state when the MCU main control circuit is in an uncompleted initialization state at the moment of power-on, burning the power tube. After the MCU main control circuit completes initialization and the power supply is stable, the startup delay ends and the drive enable is restored, which also greatly improves the reliability of the controller;

[0017] 3. The circuit has two short-circuit protection modes: current limiting non-stop protection and over-current shutdown protection. When a sudden short-circuit fault occurs in the motor or controller, it can effectively ensure that the controller hardware will not be catastrophically damaged, ensuring the integrity of the controller hardware in the event of a sudden short-circuit fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1This is a schematic diagram of the short-circuit protection circuit structure of a high-power brushless DC fan controller of the utility model;

[0019] Figure 2 This is the principle diagram of the delayed soft start circuit of the utility model;

[0020] Figure 3 This is the principle diagram of the current limiting protection detection circuit of the utility model;

[0021] Figure 4 This is the principle diagram of the overcurrent protection detection circuit of the utility model;

[0022] Figure 5 This is the schematic diagram of the fan restart signal circuit of the utility model;

[0023] Figure 6 This is the schematic diagram of the overcurrent feedback signal circuit of the utility model;

[0024] Figure 7 This is the schematic diagram of the MCU main control circuit of the utility model;

[0025] Figure 8 This is a schematic diagram of the switch circuit of the utility model. DETAILED DESCRIPTION

[0026] The technical solution of the utility model is further described below, but the scope of protection required is not limited to the description.

[0027] like Figure 1 The figure shows a schematic diagram of the short-circuit protection circuit structure of a high-power brushless DC fan controller of the utility model; a short-circuit protection circuit of a high-power brushless DC fan controller includes a delayed soft start circuit, a current limiting protection detection circuit, and an overcurrent protection detection circuit. The delayed soft start circuit, the current limiting protection detection circuit, and the overcurrent protection detection circuit are all connected to the switch circuit, and the overcurrent protection detection circuit is connected to the MCU main control circuit through the overcurrent feedback signal circuit and the fan restart signal circuit. The overcurrent protection detection circuit and the current limiting protection detection circuit are also connected to the bus current end of the motor controller, the input end of the delayed soft start circuit is connected to the DC power supply input end, and the output end of the switch circuit is connected to the motor drive IC enable port.

[0028] like Figure 2The schematic diagram of the time-delay soft-start circuit of the utility model is shown; the time-delay soft-start circuit includes an inverter F1, a switching diode D4, a resistor R9, and a capacitor C4; the input end of the inverter F1 is connected to the anode of the diode D4, the resistor R9, and one end of the capacitor C4; the output end of the inverter F1 is connected to the switching diode D5, the switching diode D2, and the switching diode D3 in sequence, the power supply end is connected to the positive electrode of the 5V DC power supply, and the ground end is connected to the ground of the 5V DC power supply; the cathode of the switching diode D4 and the other end of the resistor R9 are both connected to the positive electrode of the 5V DC power supply; the other end of the capacitor C4 is connected to the ground of the 5V DC power supply;

[0029] The inverter F1 is a single-channel inverter;

[0030] In this embodiment, the motor driver IC chip itself is enabled by reverse logic. When a high level is input to the enable port of the motor driver IC chip, the drive enable is turned off. When a low level is input, it returns to normal and triggers the drive enable.

[0031] Specifically, at the moment of power-on, the RC circuit composed of resistor R9 and capacitor C4 is powered on with a delay, and the voltage of capacitor C4 is zero at the moment of charging. At this time, pin 2 of the input end of the single-channel inverter F1 is at a low level of 0V, and pin 4 of the output end is at a high level of +5V. The three diodes of switching diode D2, switching diode D3, and switching diode D5 are turned on, which directly turns on the transistor Q1 in the switching circuit, and the ICC end outputs a high level, which is input to the enable port of the motor driver IC chip, and the driver IC enable end is closed, so that the six power tubes of the three-phase full bridge connected to the output end of the motor driver IC chip are all turned off, which can prevent the MCU main control circuit from being in an uncompleted initialization state when the controller is powered on, and the PWM wave it sends is in an uncertain high or low state, burning the motor driver IC chip and the power tube;

[0032] As the capacitor C4 in the RC circuit is gradually fully charged to 5V, the input and output levels of the single-channel inverter F1 are flipped, and the single-channel inverter F1 outputs a low level of 0V. The back-end switching diodes D2, D3, and D5 cannot be turned on, causing the transistor Q1 in the switching circuit to be turned off, and the ICC terminal output is a low level of 0V, which is input to the motor driver IC enable port to restore the normal enablement of the driver IC chip; the controller startup delay time is determined by R9*C4, and the RC delay ends, triggering the driver IC chip enable, and the controller starts to start normally.

[0033] like Figure 3The schematic diagram of the current limiting protection detection circuit of the utility model is shown; the current limiting protection detection circuit includes an operational amplifier Y1A, a resistor R2, a resistor R3 and a capacitor C1; one end of the resistor R2 and the resistor R3 connected in parallel is connected to the inverting input end of the operational amplifier Y1A, the resistor R1 and one end of the capacitor C1, and the other end is connected to the other end of the capacitor C1 and then connected to the 5V DC power supply ground; the non-inverting input end of the operational amplifier Y1A is connected to one end of the resistor R6 and the resistor R8, the output end is connected to the other end of the resistor R8 and the anode of the switching diode D1, the power supply end is connected to the positive electrode of the 5V DC power supply, and the power supply ground is connected to the 5V DC power supply ground; the other end of the resistor R6 is connected to one end of the capacitor C3 and the resistor R5; the other end of the resistor R5 is connected to one end of the resistor R4 and the capacitor C2; the other ends of the capacitor C2 and the capacitor C3 are connected to the 5V DC power supply ground; the other end of the resistor R4 is connected to the bus current end of the motor controller; the other end of the resistor R1 is connected to the positive electrode of the 5V DC power supply;

[0034] The operational amplifier Y1A is a precision rail-to-rail operational amplifier;

[0035] Specifically, during the normal operation of the controller, the current limiting protection detection circuit part adopts the precision rail-to-rail operational amplifier Y1A plus the positive feedback resistor R8 to form a hysteresis comparator. The voltage divided by the resistors R1, R2, and R3 is input to the inverting input terminal of the precision rail-to-rail operational amplifier Y1A as the reference value voltage of the current limiting protection. The voltage on the bus current sampling resistor is collected at its non-inverting input terminal and compared with the current limiting protection reference value. When the bus current of the controller exceeds the current limiting protection value, the precision rail-to-rail operational amplifier Y1A outputs a 5V high voltage. The voltage at the output terminal of the motor driver IC is high, which turns off the transistor Q1 in the switch circuit, and the ICC terminal outputs a high level, turning off the motor driver IC enable terminal, so that the six power tubes of the three-phase full-bridge connected to the output terminal of the motor driver IC chip are all turned off, and the controller performs current limiting protection, and the fan continues to operate by inertia without power interruption; when the bus current recovers to below the current limiting value, the precision rail-to-rail operational amplifier Y1A outputs a 0V low level, so that the transistor Q1 in the switch circuit is turned off, and the ICC terminal outputs a low level, triggering the motor driver IC chip to enable, releasing the controller current limiting protection, and the fan resumes normal operation.

[0036] like Figure 4The schematic diagram of the overcurrent protection detection circuit of the utility model is shown; the overcurrent protection detection circuit includes an operational amplifier Y1B, a resistor R11, a resistor R12, and a capacitor C5; one end of the resistor R11 and the resistor R12 connected in parallel is connected to the inverting input end of the operational amplifier Y1B, the capacitor C5 and one end of the resistor R10, and the other end is connected to the other end of the capacitor C5 and then connected to the 5V DC power supply ground; the non-inverting input end of the operational amplifier Y1B is connected to one end of the resistor R13 and the resistor R14, and the output end is connected to the anodes of the switching diode D6 and the switching diode D7; the other end of the resistor R14 is connected to the cathode of the switching diode D7; the other end of the resistor R13 is connected to the bus current end of the motor controller; the other end of the resistor R10 is connected to the positive electrode of the 5V DC power supply;

[0037] The operational amplifier Y1B is a precision rail-to-rail operational amplifier;

[0038] Specifically, the voltage divided by resistors R10, R11, and R12 is input as the reference value voltage of the overcurrent protection to the inverting input terminal of the precision rail-to-rail operational amplifier Y1B, and the voltage on the bus current sampling resistor is collected at its non-inverting input terminal, and compared with the overcurrent protection reference value. When the bus current of the controller abnormally exceeds the overcurrent protection value instantaneously, the overcurrent protection reference value is set to be greater than the current limiting protection reference value, and the precision rail-to-rail operational amplifier Y1B outputs a high level, the transistor Q1 in the switching circuit is turned on, and the ICC terminal outputs a high level, turning off the motor drive IC enable terminal, so that the output terminal of the motor drive IC chip is connected to the three-phase six-way power tube, and all are turned off. Since a switching diode D7 is added to the positive feedback loop of the precision rail-to-rail operational amplifier Y1B, the non-inverting input terminal of the precision rail-to-rail operational amplifier Y1B is always 5V after the overcurrent protection occurs, which always exceeds the reference value, and the reference value is much smaller than 5V, so that the driver IC enable terminal is always in a closed state, the fan gradually stops running, and the controller is not powered off.

[0039] like Figure 5 The schematic diagram of the fan restart signal circuit of the utility model is shown; the fan restart signal circuit includes a photocoupler G1 and an NPN transistor Q2; pin 1 of the photocoupler G1 is connected to one end of a resistor R18, pin 2 is connected to a 3.3V DC power supply ground, pin 3 is connected to one end of a capacitor C6 and then to a 5V DC power supply ground, and pin 4 is connected to the other end of the capacitor C6, the resistor R16 and one end of the resistor R15; the other end of the resistor R15 is connected to the base of the NPN transistor Q2; the collector of the NPN transistor Q2 is connected to the non-inverting input end of the operational amplifier Y1B, the emitter is connected to the 5V DC power supply ground, and the other end of the resistor R16 is connected to the positive electrode of the 5V DC power supply;

[0040] like Figure 6The schematic diagram of the overcurrent feedback signal circuit of the utility model is shown; the overcurrent feedback signal circuit includes a photocoupler G2, a resistor R17, and a capacitor C7; the pin 1 of the photocoupler G2 is connected to the output end of the operational amplifier Y1B through a resistor R19, the pin 2 is connected to the 5V DC power supply ground, the pin 3 is connected to one end of the capacitor C7 and then connected to the 3.3V DC power supply ground, the pin 4 is connected to the other end of the capacitor C7 and one end of the resistor R17; the other end of the resistor R17 is connected to the positive electrode of the 3.3V DC power supply;

[0041] like Figure 7 The schematic diagram of the MCU main control circuit of the utility model is shown; the MCU main control circuit includes an MCU main control chip U1, and the 6th pin, 19th pin, 27th pin and 1st pin of the MCU main control chip U1 are connected to one end of the capacitor C22, capacitor C23, capacitor C24, capacitor C25, capacitor C26 and capacitor C27 in parallel and then connected to the positive electrode of the 3.3V DC power supply, the 35th pin is connected to the 3.3V DC power supply ground through the resistor R22, the 4th pin is connected to the resistor R23 and one end of the capacitor C28, and the 12th pin is connected to the photoelectric through the resistor R18. Pin 1 of the coupler G1 is connected, pin 13 is connected to pin 4 of the photocoupler G2, pin 17 is connected to the 3.3V DC power ground through a resistor R24, and pins 5, 36, 26 and 18 are all connected to the 3.3V DC power ground; the other ends of the capacitors C22, C23, C24, C25, C26 and C27 connected in parallel are connected to the 3.3V DC power ground; the other end of the resistor R23 is connected to the positive electrode of the 3.3V DC power supply, and the other end of the capacitor C28 is connected to the 3.3V DC power ground;

[0042] Specifically, when the controller has an instantaneous short-circuit overcurrent protection and the fan stops, the high level output of the precision rail-to-rail operational amplifier Y1B is input to the strong current input side of the photoelectric coupler G2 through the resistor R19. After being electrically isolated by the photoelectric coupler G2, it is pulled up to a +3.3V weak current signal by the resistor R17 on the weak current output side, which is the overcurrent shutdown signal. The signal is fed back to the I / O port of the MCU main control circuit. After the MCU main control circuit receives the overcurrent shutdown signal command, it issues a fan restart command +3.3V high level signal after a few seconds, which is input through the resistor R18. To the weak current input side of the photocoupler G1, after being electrically isolated by the photocoupler G1, it is pulled up to a +5V strong current signal by the strong current output side resistor R16, which is the fan restart signal and input to the base of the transistor Q2. The emitter of Q2 is connected to PGND1, and the collector is connected to the 5th pin of the precision rail-to-rail operational amplifier Y1B. At this time, the 5th pin is a +5V high level. At this time, Q2 is turned on, and the 5th pin of the precision rail-to-rail operational amplifier Y1B is instantly pulled down. The overcurrent shutdown protection is released, and the MCU main control circuit sends a low-level signal again, which turns off the transistor Q2 and the fan resumes normal operation.

[0043] like Figure 8 The schematic diagram of the switch circuit of the utility model is shown; the switch circuit includes an NPN transistor Q1, the base of the NPN transistor Q1 is connected to the cathodes of the switch diode D3, the switch diode D1 and the switch diode D6, the collector is connected to the positive electrode of the 5V DC power supply, and the emitter is connected to the motor drive IC enable port through the resistor R7;

[0044] Specifically, combined Figure 1 As shown in the schematic diagram of the short-circuit protection circuit structure of the high-power brushless DC fan controller of the present invention, when the output of any path among path 1, path 2 and path 3 is high level, the NPN transistor Q1 will be turned on and the motor drive IC will be turned off.

[0045] The utility model discloses a high-power brushless DC fan controller short-circuit protection circuit, which can make the controller turn off the drive enable at the moment of power-on to realize delayed soft start, and has two protection modes: current limiting without shutdown protection and overcurrent shutdown protection. Both modes collect bus current. When the bus current exceeds the overcurrent protection reference value, the circuit will always turn off the controller drive enable, and transmit the fan state to the MCU main control circuit through the overcurrent feedback signal circuit. After being processed by the MCU main control circuit, the fan restart command signal is issued, and the overcurrent protection is released through the fan restart signal circuit, so that the fan restarts and works normally. The utility model solves the problem of rapid burning of the power tube caused by the instantaneous surge of bus current when the bridge arm is directly connected, phase-to-phase or relatively short-circuited in the high-power fan controller, and can greatly increase the response speed of the controller short-circuit protection.

Claims

1. A short-circuit protection circuit for a high-power brushless DC fan controller, characterized in that: It includes a delayed soft start circuit, a current limiting protection detection circuit, and an overcurrent protection detection circuit. The delayed soft start circuit, the current limiting protection detection circuit, and the overcurrent protection detection circuit are all connected to the switch circuit. The overcurrent protection detection circuit is connected to the MCU main control circuit through an overcurrent feedback signal circuit and a fan restart signal circuit. The overcurrent protection detection circuit and the current limiting protection detection circuit are also connected to the bus current end of the motor controller. The input end of the delayed soft start circuit is connected to the DC power supply input end, and the output end of the switch circuit is connected to the motor driver IC enable port.

2. A short-circuit protection circuit for a high-power brushless DC fan controller as claimed in claim 1, characterized in that: The delayed soft start circuit includes an inverter F1, a switching diode D4, a resistor R9, and a capacitor C4; the input end of the inverter F1 is connected to the anode of the diode D4, the resistor R9, and one end of the capacitor C4; the output end of the inverter F1 is connected to the switching diode D5, the switching diode D2, and the switching diode D3 in sequence, the power supply end is connected to the positive electrode of the 5V DC power supply, and the ground end is connected to the ground of the 5V DC power supply; the cathode of the switching diode D4 and the other end of the resistor R9 are both connected to the positive electrode of the 5V DC power supply; the other end of the capacitor C4 is connected to the ground of the 5V DC power supply.

3. The short-circuit protection circuit of a high-power brushless DC fan controller according to claim 1, characterized in that: The current limiting protection detection circuit includes an operational amplifier Y1A, a resistor R2, a resistor R3 and a capacitor C1; one end of the resistor R2 and the resistor R3 connected in parallel is connected to the inverting input end of the operational amplifier Y1A, the resistor R1 and one end of the capacitor C1, and the other end is connected to the other end of the capacitor C1 and then connected to the 5V DC power supply ground; the non-inverting input end of the operational amplifier Y1A is connected to one end of the resistor R6 and the resistor R8, the output end is connected to the other end of the resistor R8 and the anode of the switching diode D1, the power supply end is connected to the positive electrode of the 5V DC power supply, and the power supply ground is connected to the 5V DC power supply ground; the other end of the resistor R6 is connected to one end of the capacitor C3 and the resistor R5; the other end of the resistor R5 is connected to one end of the resistor R4 and the capacitor C2; the other ends of the capacitor C2 and the capacitor C3 are connected to the 5V DC power supply ground; the other end of the resistor R4 is connected to the bus current end of the motor controller; the other end of the resistor R1 is connected to the positive electrode of the 5V DC power supply.

4. The short-circuit protection circuit of a high-power brushless DC fan controller according to claim 1, characterized in that: The overcurrent protection detection circuit includes an operational amplifier Y1B, a resistor R11, a resistor R12, and a capacitor C5; one end of the resistor R11 and the resistor R12 connected in parallel is connected to the inverting input end of the operational amplifier Y1B, the capacitor C5, and one end of the resistor R10, and the other end is connected to the other end of the capacitor C5 and then connected to the ground of a 5V DC power supply; the non-inverting input end of the operational amplifier Y1B is connected to one end of the resistor R13 and the resistor R14, and the output end is connected to the anodes of the switching diode D6 and the switching diode D7; the other end of the resistor R14 is connected to the cathode of the switching diode D7; the other end of the resistor R13 is connected to the bus current end of the motor controller; the other end of the resistor R10 is connected to the positive electrode of the 5V DC power supply.

5. The short-circuit protection circuit of a high-power brushless DC fan controller according to claim 1, characterized in that: The fan restart signal circuit includes a photocoupler G1 and an NPN transistor Q2; pin 1 of the photocoupler G1 is connected to one end of a resistor R18, pin 2 is connected to a 3.3V DC power supply ground, pin 3 is connected to one end of a capacitor C6 and then to a 5V DC power supply ground, and pin 4 is connected to the other end of the capacitor C6, the resistor R16 and one end of the resistor R15; the other end of the resistor R15 is connected to the base of the NPN transistor Q2; the collector of the NPN transistor Q2 is connected to the non-inverting input end of the operational amplifier Y1B, the emitter is connected to the 5V DC power supply ground, and the other end of the resistor R16 is connected to the positive electrode of the 5V DC power supply.

6. The short-circuit protection circuit of a high-power brushless DC fan controller according to claim 1, characterized in that: The overcurrent feedback signal circuit includes a photocoupler G2, a resistor R17, and a capacitor C7; pin 1 of the photocoupler G2 is connected to the output end of the operational amplifier Y1B through a resistor R19, pin 2 is connected to the 5V DC power supply ground, pin 3 is connected to one end of the capacitor C7 and then to the 3.3V DC power supply ground, and pin 4 is connected to the other end of the capacitor C7 and one end of the resistor R17; the other end of the resistor R17 is connected to the positive electrode of the 3.3V DC power supply.

7. The short-circuit protection circuit of a high-power brushless DC fan controller according to claim 1, characterized in that: The MCU main control circuit includes an MCU main control chip U1, wherein the 6th pin, the 19th pin, the 27th pin and the 1st pin of the MCU main control chip U1 are connected to one end of the capacitor C22, the capacitor C23, the capacitor C24, the capacitor C25, the capacitor C26 and the capacitor C27 in parallel and then connected to the positive electrode of the 3.3V DC power supply, the 35th pin is connected to the 3.3V DC power supply ground through the resistor R22, the 4th pin is connected to one end of the resistor R23 and the capacitor C28, the 12th pin is connected to the 1st pin of the photoelectric coupler G1 through the resistor R18. The first embodiment of the present invention is connected to the optical coupler G2, the first pin 13 is connected to the first pin 4 of the optical coupler G2, the first pin 17 is connected to the 3.3V DC power supply ground through the resistor R24, the first pin 5, the first pin 36, the first pin 26 and the first pin 18 are all connected to the 3.3V DC power supply ground; the other end of the capacitor C22, the capacitor C23, the capacitor C24, the capacitor C25, the capacitor C26 and the capacitor C27 after being connected in parallel is connected to the 3.3V DC power supply ground; the other end of the resistor R23 is connected to the positive electrode of the 3.3V DC power supply, and the other end of the capacitor C28 is connected to the 3.3V DC power supply ground.

8. The short-circuit protection circuit of a high-power brushless DC fan controller according to claim 1, characterized in that: The switching circuit includes an NPN transistor Q1, a base of which is connected to the cathodes of the switching diode D3, the switching diode D1 and the switching diode D6, a collector is connected to the positive electrode of a 5V DC power supply, and an emitter is connected to an enable port of a motor driver IC through a resistor R7.

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