Overcurrent protection circuit of three-path interleaved BOOST circuit

Abstract

The utility model relates to an overcurrent protection circuit of a three-path interleaved BOOST circuit, which realizes peak value overcurrent protection, total current peak value protection and total current effective value overcurrent protection of each path of BOOST switch tube through a driving chip with overcurrent protection function and adding a path of total current peak value detection and filtering processing as an effective value current detection circuit. In addition, a path of total current sampling is added, an instantaneous value signal of a total current sampling signal is sent to a digital control DSC internal comparator to perform three paths of BOOST and close driving protection at the same time, and a signal of the total current sampling signal after high-frequency pulse filtering is sent to an analog sampling port of the digital control DSC to perform effective value calculation so as to realize effective value protection. Three-path interlaced BOOS overcurrent protection is realized, rapid protection on the peak value, overcurrent and effective value overcurrent of the input total current is realized, the peak value overcurrent protection and effective value overcurrent precision of the input total current are high, and high-precision overcurrent protection on the input total current can be realized.

Description

Technical Field

[0001] The utility model belongs to the field of electronic circuit technology improvement, and in particular relates to an overcurrent protection circuit of a three-way staggered parallel BOOST circuit. Background Art

[0002] At present, the industry's common overcurrent protection technology for two-way staggered parallel BOOST circuits is to sample the high-frequency current of each BOOST circuit through resistance sampling or current sensor, and then quickly compare the peak value of each high-frequency current with the preset current peak protection value. Through analog chips or digital controller chips DSC, timely control of each drive signal can be achieved, which can realize wave-by-wave protection to protect the reliable operation of the power switch tube. In principle, the overcurrent protection technology of the three-way staggered parallel BOOST circuit can refer to the overcurrent protection technology of the two-way BOOST circuit. No analog control chip that can realize the three-way wave-by-wave protection has been found yet. However, the implementation method is relatively complicated. Even if it is digitally controlled, the conventional digital control chip DSC generally has only two internal high-speed comparators. Other effective measures need to be taken to achieve wave-by-wave protection control of each channel. A DSC with more comparators is costly and inconvenient for practical use. In addition, the DSC itself needs to have the function of correspondingly configuring each internal high-speed comparator with each drive. The industry also has peak detection and protection for each high-frequency current of the three-way staggered parallel BOOST circuit, but due to the number of high-speed comparisons inside the DSC, wave-by-wave protection is generally not achieved. Instead, when a peak overcurrent occurs in any one of the BOOST circuits, the drivers of the three-way BOOST switch tubes are all turned off at the same time. This protection method can also ensure the reliability of the switch tube, but reduces the stability of the output performance and the dynamic response performance. Utility Model Content

[0003] In view of the above problems, the utility model proposes an optimal technical solution. First, the cost is relatively low. The driver chip itself is selected to have an approximate wave-by-wave protection function. This driver chip can achieve rapid shutdown protection of the peak current for each BOOST switch tube. The price of this driver chip is equivalent to or slightly higher than that of other applicable conventional driver chips. The peripheral circuit of the driver chip is simple and the cost is low. Second, the overcurrent protection function is comprehensive. In addition to the overcurrent protection function of the driver chip itself, a peak value detection of the total current is added. At the same time, it is also filtered and processed as an effective value current detection circuit, which can realize the switching of each BOOST circuit. The peak overcurrent protection of the switch tube can also be used for total current peak protection and total current effective value overcurrent protection; thirdly, the circuit structure is simple, and only the overcurrent protection provided by the driver chip is needed, eliminating the sampling resistor or current sensor and sampling circuit for each switch tube current detection, which also slightly reduces the loss and saves cost and space. In addition, one more total current sampling is added, and the instantaneous value signal of the total current sampling signal is sent to the internal comparator of the digitally controlled DSC to perform three-way BOOST and turn off the drive protection at the same time, and the signal of the total current sampling signal after high-frequency pulsation is filtered is sent to the analog sampling port of the digitally controlled DSC for effective value calculation to achieve effective value protection. This preferred technical solution is suitable for both the three-way staggered BOOST parallel circuit with DC input and the three-way staggered BOOST parallel power factor correction circuit with single-phase bridge input.

[0004] The utility model is implemented as follows: an overcurrent protection circuit of a three-way staggered parallel BOOST circuit, comprising: a positive input VIN_P and a negative input VIN_N, a positive output VOUT_P and a negative output GND_D, a diode VD1, a diode VD2 and a diode VD3, an inductor L1, an inductor L2 and an inductor L3, a first drive signal, a second drive signal and a third drive signal, a first drive circuit with fast overcurrent protection, a second drive circuit with fast overcurrent protection and a third drive circuit with fast overcurrent protection, a current sampling amplifier circuit and a power frequency current signal and a high-frequency current signal output by the circuit, a switch tube VT1, a switch tube VT2 and a switch tube VT3, a resistor R24, a resistor R27 and a resistor R28, a resistor R1, a resistor R6 and a resistor R11, a diode VD4, a diode VD6, a diode VD8 and a capacitor C9;

[0005] The positive input VIN_P is connected to one end of the inductor L1, one end of the inductor L2 and one end of the inductor L3;

[0006] The other end of the inductor L1 is connected to the anode of the diode VD1, the drain of the switch tube VT1 and the cathode of the diode VD4, the cathode of the diode VD1 is connected to the cathode of the diode VD2, the cathode of the diode VD3, one end of the capacitor C9 and the output positive VOUT_P, the gate of the switch tube VT1 is connected to the driving output end of the first driving circuit with fast overcurrent protection, the input of the first driving circuit with fast overcurrent protection is connected to the first driving signal, the anode of the diode VD4 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the first driving circuit with fast overcurrent protection, the source of VT1 is connected to the output ground GND_D, and the output ground GND_D is also the working reference ground;

[0007] The other end of the inductor L2 is connected to the anode of the diode VD2, the drain of the switch tube VT2 and the cathode of the diode VD6, the gate of the switch tube VT2 is connected to the driving output end of the second driving circuit with fast overcurrent protection, the input of the second driving circuit with fast overcurrent protection is connected to the second driving signal, the anode of the diode VD6 is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the second driving circuit with fast overcurrent protection, and the source of VT2 is connected to the output ground GND_D;

[0008] The other end of the inductor L3 is connected to the anode of the diode VD3, the drain of the switch tube VT3 and the cathode of the diode VD8, the gate of the switch tube VT3 is connected to the driving output end of the third driving circuit with fast overcurrent protection, the input of the third driving circuit with fast overcurrent protection is connected to the third driving signal, the anode of the diode VD8 is connected to one end of the resistor R11, the other end of the resistor R11 is connected to the third driving circuit with fast overcurrent protection, and the source of VT3 is connected to the output ground GND_D;

[0009] Furthermore, the negative input VIN_N is connected to one end of the resistor R24, one end of the resistor R27, one end of the resistor R28 and a current sampling signal input end of the current sampling amplifier circuit, and the other end of the resistor R24, the other end of the resistor R27, the other end of the resistor R28 and another current sampling signal input end of the current sampling amplifier circuit are connected to GNDD_D, and the current sampling amplifier circuit outputs an industrial frequency current signal and a high-frequency current signal.

[0010] In addition, to realize the protection function of specific front-end and rear-end circuits, a main control unit circuit adapted thereto is also required, which will not be described in detail here.

[0011] A further technical solution of the present utility model is: the first drive circuit, the second drive circuit and the third drive circuit are arranged in parallel.

[0012] A further technical solution of the utility model is: the first drive circuit, the second drive circuit and the third drive circuit have the same structure, which include a chip D1, a resistor R3, a capacitor C1, a capacitor C3, a capacitor C5, a capacitor C2, a capacitor C4, a capacitor C6, a resistor R2, a resistor R4, a resistor R5 and a diode VD5, the first pin of the chip D1 is respectively connected to one end of the resistor R3 and one end of the capacitor C5, the second pin of the chip D1 is connected to one end of the capacitor C3, the fourth pin of the chip D1 is connected to one end of the capacitor C1, and the fifth pin of the chip D1 is respectively connected to the capacitor C 4, one end of capacitor C6 and power supply VCC+20V, the 6th pin of the chip D1 is connected to one end of the capacitor C2, the 8th pin of the chip D1 is respectively connected to the other end of the capacitor C2, one end of the resistor R2, and one end of the resistor R4, the other end of the resistor R4 is connected to the cathode of the diode VD5, the other end of the resistor R2 and the anode of the diode VD5 are respectively connected to one end of the resistor R5, the 7th pin of the chip D1, the other end of the capacitor C3, the other end of the capacitor C5, the other end of the capacitor C4, the other end of the capacitor C6 and the other end of the resistor R5 are grounded respectively.

[0013] A further technical solution of the utility model is that the output end of the current sampling and amplifying circuit outputs a power frequency current signal and a high frequency current signal respectively.

[0014] A further technical solution of the utility model is: the current sampling amplifier circuit includes a chip D4, a resistor R16, a resistor R17, a capacitor C23, a capacitor C24, a diode VD10, a capacitor C22, a resistor R19, a capacitor C21, a resistor R18, a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R25, a resistor R26 and a capacitor C26, the first foot of the chip D4 is respectively connected to one end of the capacitor C12, one end of the resistor R19 and one end of the resistor R17, the other end of the resistor R17 is respectively connected to the third foot of the diode VD10, one end of the capacitor C24 and one end of the resistor R16, the other end of the resistor R16 is respectively connected to one end of the capacitor C23 and the power frequency current signal, the second foot of the chip D4 is respectively connected to the first foot of the diode VD10, the other end of the capacitor C23 and the other end of the capacitor C24, the diode The second pin of the tube VD10 is connected to the power supply VCC+3.3VA, the third pin of the chip D1 is respectively connected to one end of the resistor R26, one end of the capacitor C27, one end of the resistor R18 and one end of the resistor R22, the other end of the resistor R18 is respectively connected to one end of the capacitor C20 and the power supply VCC+3.3VA, the fourth pin of the chip D4 is respectively connected to the other end of the resistor R19, the other end of the capacitor C21 and one end of the resistor R20, the other end of the resistor R20 is respectively connected to one end of the resistor R21 and one end of the capacitor C25, the other end of the resistor R22 is respectively connected to one end of the capacitor C26 and one end of the resistor R23, the other end of the capacitor C22, the other end of the capacitor C20, the other end of the capacitor C25, the other end of the capacitor C26, the other end of the capacitor C27, the other end of the resistor R26 and the other end of the resistor R25 are respectively grounded.

[0015] The working principle of the utility model is specifically described as follows:

[0016] The first drive signal, the second drive signal and the third drive signal are three drive signals with phases staggered by 120° from each other given by the main control unit circuit; the first drive signal, the second drive signal and the third drive signal are respectively input as drive signals to the first drive circuit with fast overcurrent protection, the second drive circuit with fast overcurrent protection and the third drive circuit with fast overcurrent protection;

[0017] The first drive circuit with fast overcurrent protection, the second drive circuit with fast overcurrent protection and the third drive circuit with fast overcurrent protection are circuits with completely identical component models and parameters. The resistor R1, the resistor R6 and the resistor R11 are resistors of the same specification and model. The diode VD4, the diode VD6 and the diode VD8 are diodes of the same specification and model. The diode VD1, the diode VD2 and the diode VD3 are diodes of the same model. The inductor L1, the inductor L2 and the inductor L3 are inductors of the same specification and model. The switch tube VT1, the switch tube VT2 and the switch tube VT3 are switch tubes of the same specification and model. The peak current protection point during the opening period of the switch tube VT1, the switch tube VT2 and the switch tube VT3 is set the same. The circuit principle is specifically described below by taking the peak current protection in the switch tube VT1 as an example.

[0018] In the first driving circuit with fast overcurrent protection, the potential V1 formed by the sum of the conduction voltage drop when R1 is connected to VD4 and VT1 is turned on realizes overcurrent protection for VT1. When VT1 is turned on, the first driving circuit with fast overcurrent protection will provide a current source with a constant current value of Icc to the R1 series VD4 branch. This current source is turned off when VT1 is turned off. When VT1 is turned off, the directional blocking characteristic of the diode VD4 realizes the electrical blocking isolation of the high voltage on the drain of the switch tube VT1 from the first driving circuit with fast overcurrent protection. Therefore, the reverse withstand voltage of the diode VD4 is selected to exceed the maximum voltage value of the output terminal VOUT_P to ensure sufficient current. Pressure stress derating; Under normal working conditions, the output drive signal of the first drive circuit with fast overcurrent protection and the first drive signal at its input end are drive signals of the same phase and the same logic when the hardware transmission delay is ignored, and the high-level voltage of the drive signal output to VT1 is adapted to the drive voltage required by VT1; The internal overcurrent protection voltage threshold of the first drive circuit with fast overcurrent protection is Vth_OC; When the peak current through the switch tube VT1 reaches the overcurrent protection voltage threshold Vth_OC, the first drive circuit with fast overcurrent protection will immediately shut down the drive, thereby realizing the peak overcurrent fast protection of the switch tube VT1;

[0019] When VT1 is turned on, the current is Id1, the on-resistance is Ron, the maximum current and overcurrent protection point are Id1_max, and the forward conduction voltage drop of diode VD4 is VF, then:

[0020] V1=R1·Icc+VF+Id1·Ron

[0021] When the instantaneous value of V1 reaches the overcurrent protection voltage threshold Vth_OC, the drive signal is immediately turned off, so that the overcurrent protection current Id1_max value when VT1 is turned on satisfies the following:

[0022]

[0023] Because the accuracy of the overcurrent protection voltage threshold Vth_OC is usually not high, and the on-resistance Ron of the switch tube itself changes greatly with the temperature, the protection point accuracy of Id1_max is low, and the overcurrent protection point set when working at low temperature needs to reserve a large margin. In order to ensure high-precision overcurrent protection of the switch tube and overcurrent protection of the total input current at low temperature, the peak current overcurrent protection and effective value current overcurrent protection of the total input current are added.

[0024] The total input current flowing through the sampling resistor R24, the sampling resistor R27 and the sampling resistor R28 is sampled and amplified by the current sampling and amplifying circuit, and different processing is performed, and finally the industrial frequency electrical signal and the high-frequency current signal are output. The industrial frequency current signal is sent to the main control unit circuit for effective value calculation and effective value overcurrent protection, and the high-frequency current signal is sent to the main control unit for rapid protection of total current peak overcurrent. When the total current effective value is overcurrent or the total current peak is overcurrent, the main control unit circuit promptly shuts down the first drive signal, the second drive signal and the third drive signal.

[0025] The beneficial effects of the utility model are as follows: the utility model realizes overcurrent protection for each switch tube in the three-way staggered BOOS, and can also quickly protect the input total current from peak current overcurrent and effective value overcurrent, and the peak overcurrent protection and effective value overcurrent of the input total current are highly accurate, and the input total current can be protected from overcurrent with high accuracy, the circuit structure is relatively simple, and the cost is relatively low, and it is a relatively complete overcurrent protection circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a principle block diagram of an overcurrent protection circuit of a three-way staggered parallel BOOST circuit provided by an embodiment of the utility model.

[0027] Figure 2 It is an electrical schematic diagram of an overcurrent protection circuit of a three-way staggered parallel BOOST circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0028] In order to make the technical means of the present invention clear, the preferred embodiment of the present invention is further described below in conjunction with the accompanying drawings. Figure 1 Specific implementation method Figure 2 , the main control unit circuit that needs to be matched will not be further elaborated.

[0029] like Figure 1As shown in FIG. 2 , the overcurrent protection circuit of the three-way staggered parallel BOOST circuit provided by the utility model includes: a positive input VIN_P and a negative input VIN_N, a positive output VOUT_P and a negative output GND_D, a diode VD1, a diode VD2 and a diode VD3, an inductor L1, an inductor L2 and an inductor L3, a first drive signal, a second drive signal and a third drive signal, a first drive circuit with fast overcurrent protection, a second drive circuit with fast overcurrent protection and a third drive circuit with fast overcurrent protection, a current sampling amplifier circuit and an industrial frequency current signal and a high-frequency current signal output by the circuit, Resistor R24, resistor R27 and resistor R28, resistor R1, resistor R6 and resistor R11, diode VD4, diode VD6, diode VD8 and capacitor C9; switch tube VT1, switch tube VT2 and switch tube VT3, switch tube VT1, switch tube VT2 and switch tube VT3 are silicon carbide MOSFETs in TO247-4 package. The difference between TO247-4 package and TO247-3 package of silicon carbide MOSFET is that the original source of power current is divided into the source of power current and a Kelvin source. This Kelvin source is called control source here.

[0030] The positive input VIN_P is connected to one end of the inductor L1, one end of the inductor L2 and one end of the inductor L3.

[0031] The other end of the inductor L1 is connected to the anode of the diode VD1, the drain of the switch tube VT1 and the cathode of the diode VD4. The cathode of the diode VD1 is connected to the cathode of the diode VD2, the cathode of the diode VD3, one end of the capacitor C9 and the output positive VOUT_P. The gate of the switch tube VT1 is connected to the anode of the diode VD5, one end of the resistor R2 and one end of the resistor R5. The cathode of the diode VD5 is connected to one end of the resistor R4. The other end of the resistor R2, the other end of the resistor R4, one end of the capacitor C2 and the 8th pin of the driver chip D1 are connected. The other end of the capacitor C2 is connected to the 6th pin of the driver chip D1. The anode of the diode VD4 is connected to one end of the resistor R1. The other end of the resistor R1 is connected to the 6th pin of the driver chip D1. One end is connected to one end of capacitor C1 and the 4th pin of driving chip D1, the 1st pin of driving chip D1 is connected to one end of capacitor C5 and one end of resistor R3, the other end of resistor R3 is connected to driving signal DSC_DRV1, the 2nd pin of driving chip D1 is connected to one end of capacitor C3, the 5th pin of driving chip D1 is connected to one end of capacitor C4, one end of capacitor C6 and power supply VCC+20V, the 7th pin of driving chip D1 is connected to the other end of capacitor C3, the other end of capacitor C5, the other end of capacitor C1, the other end of capacitor C4, the other end of capacitor C6, the other end of resistor R5 and the control source of switch tube VT1, and the source of switch tube VT1 is connected to working ground GND_D.

[0032] The other end of the inductor L2 is connected to the anode of the diode VD2, the drain of the switch tube VT2 and the cathode of the diode VD6. The gate of the switch tube VT2 is connected to the anode of the diode VD7, one end of the resistor R7 and one end of the resistor R10. The cathode of the diode VD7 is connected to one end of the resistor R9. The other end of the resistor R7, the other end of the resistor R9, one end of the capacitor C8 and the 8th pin of the driver chip D2 are connected. The other end of the capacitor C8 is connected to the 6th pin of the driver chip D1. The anode of the diode VD6 is connected to one end of the resistor R6. The other end of the resistor R6 is connected to one end of the capacitor C7 and the 4th pin of the driver chip D2. The driver chip D The first pin of driver chip D2 is connected to one end of capacitor C13 and one end of resistor R8, the other end of resistor R8 is connected to driving signal DSC_DRV2, the second pin of driver chip D2 is connected to one end of capacitor C10, the fifth pin of driver chip D2 is connected to one end of capacitor C11, one end of capacitor C12 and power supply VCC+20V, the seventh pin of driver chip D2 is connected to the other end of capacitor C10, the other end of capacitor C13, the other end of capacitor C7, the other end of capacitor C11, the other end of capacitor C12, the other end of resistor R10 and control source of switch tube VT2, and the source of switch tube VT2 is connected to working ground GND_D.

[0033] The other end of the inductor L3 is connected to the anode of the diode VD3, the drain of the switch tube VT3 and the cathode of the diode VD8. The gate of the switch tube VT3 is connected to the anode of the diode VD9, one end of the resistor R12 and one end of the resistor R15. The cathode of the diode VD9 is connected to one end of the resistor R14. The other end of the resistor R14, the other end of the resistor R12, one end of the capacitor C15 and the 8th pin of the driver chip D3 are connected. The other end of the capacitor C15 is connected to the 6th pin of the driver chip D3. The anode of the diode VD8 is connected to one end of the resistor R11. The other end of the resistor R11 is connected to one end of the capacitor C14 and the 4th pin of the driver chip D3. The first pin of the driving chip D3 is connected to one end of the capacitor C17 and one end of the resistor R13, the other end of the resistor R13 is connected to the driving signal DSC_DRV3, the second pin of the driving chip D3 is connected to one end of the capacitor C16, the fifth pin of the driving chip D3 is connected to one end of the capacitor C18, one end of the capacitor C19 and the power supply VCC+20V, the seventh pin of the driving chip D3 is connected to the other end of the capacitor C16, the other end of the capacitor C14, the other end of the capacitor C17, the other end of the capacitor C18, the other end of the capacitor C19, the other end of the resistor R15 and the control source of the switch tube VT3, and the source of the switch tube VT3 is connected to the working ground GND_D.

[0034] The negative input VIN_N is connected to one end of the resistor R24, one end of the resistor R27, one end of the resistor R28 and one end of the resistor R21. The other end of the resistor R24, the other end of the resistor R27, the other end of the resistor R28 and one end of the resistor R23 are connected to the working ground GND_D. The other end of the resistor R21 is connected to one end of the resistor R20 and one end of the capacitor C25. The other end of the capacitor C25 is connected to the working analog ground GND_A. The other end of the resistor R20 is connected to one end of the resistor R19, one end of the capacitor C21, one end of the resistor R25 and the working analog ground GND_A. The other end of resistor R25 is connected to the working analog ground GND_A, the other end of resistor R19, the other end of capacitor C21, and one end of resistor R17 are connected to the output pin 1 of op amp D4, the other end of resistor R23 is connected to one end of resistor R22 and one end of capacitor C26, the other end of capacitor C26 is connected to the working analog ground GND_A, the other end of resistor R22 is connected to one end of resistor R18, one end of resistor R26, one end of capacitor C27 and the same-direction input pin 3 of op amp D4, resistor R18 The other end of the resistor R17 and one end of the resistor R16, one end of the capacitor C24 and the third end of the diode VD10 are connected to generate a high-frequency current signal COMP. 1A_ISE2_DSC, the second pin of the diode VD10 is connected to the power supply VCC+3.3VA, the first pin of the diode VD10, the other end of the capacitor C24 and one end of the capacitor C23 are connected to the working analog ground GND_A, the resistor R16 is connected to the other end of the capacitor C23 to generate the industrial frequency current signal ISE2_DSC, the working ground GND_D and the working analog ground GND_A are short-circuited at a suitable position on the PCB through the zero-ohm resistor R29 to minimize the interference of the main power circuit and the drive circuit to the current sampling and amplifier circuit.

[0035] In this embodiment, the driver chip D1, the driver chip D2 and the driver chip D3 are of IVCR1401, the typical value of the overcurrent protection voltage threshold Vth_OC of the driver chip IVCR1401 is 9.5V, the constant current value Icc is 1mA, and the unit of the resistor R1 is KΩ, so the peak overcurrent protection point of the three-way staggered parallel BOOST switch tube is as follows:

[0036]

[0037] The above description is only a typical implementation of the present invention. For example, in the embodiment, the switch tubes VT1, VT2 and VT3 are all silicon carbide MOSFETs, and suitable MOSFETs and IGBTs can also be directly selected as replacements. The total current sampling is not limited to the resistance sampling method. For example, a Hall current sensor can also directly sample the total current signal.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An overcurrent protection circuit of three-way staggered parallel BOOST circuits, characterized in that: The overcurrent protection circuit of the three-way staggered parallel BOOST circuit includes a first drive signal, a second drive signal, a third drive signal, a first drive circuit, a second drive circuit, a third drive circuit, a current sampling amplifier circuit, a positive input VIN_P, a negative input VIN_N, a positive output VOUT_P, a negative output GND_D, an inductor L1, an inductor L2, an inductor L3, a diode VD1, a diode VD2, a diode VD3, a switch tube VT1, a switch tube VT2, a switch tube VT3, a resistor R24, a resistor R27, a resistor R28, a capacitor C9, a resistor R1, a diode VD4, a resistor R6, a diode VD6, a resistor The output end of the first drive signal is connected to the input end of the first drive circuit, the output end of the second drive signal is connected to the input end of the second drive circuit, the output end of the third drive signal is connected to the input end of the third drive circuit, the input end of the current sampling amplifier circuit is respectively connected to one end of the resistor R24, one end of the resistor R27, one end of the resistor R28 and the negative input VIN_N, the positive input VIN_P is respectively connected to one end of the inductor L1, one end of the inductor L2 and one end of the inductor L3, the other end of the inductor L1 is respectively connected to the anode of the diode VD1, the diode The cathode of the diode VD4 and the drain of the switch tube VT1, the anode of the diode VD4 is connected to the input end of the first drive circuit through the resistor R1, the output end of the first drive circuit is connected to the gate of the switch tube VT1, the other end of the inductor L2 is respectively connected to the anode of the diode VD2, the cathode of the diode VD2 and the drain of the switch tube VT2, the anode of the diode VD6 is connected to the input end of the second drive circuit through the resistor R6, the output end of the second drive circuit is connected to the gate of the switch tube VT2, the other end of the inductor L3 is respectively connected to the anode of the diode VD3, the cathode of the diode VD8 and the drain of the switch tube VT2. The drain of the switch tube VT3, the cathode of the diode VD8 is connected to the input end of the third drive circuit through the resistor R11, the output end of the third drive circuit is connected to the gate of the switch tube VT3, the cathode of the diode VD1, the cathode of the diode VD2, the cathode of the diode VD3 and one end of the capacitor C9 are respectively connected to the output positive VOUT_P, the source of the switch tube VT1, the source of the switch tube VT2, the source of the switch tube VT3, the other end of the capacitor C9, the other end of the resistor R24, the other end of the resistor R27, the input end of the current sampling amplifier circuit and the other end of the resistor R28 are respectively connected to the output negative GND_D.

2. The overcurrent protection circuit of the three-way staggered parallel BOOST circuit according to claim 1 is characterized in that: The first driving circuit, the second driving circuit and the third driving circuit are arranged in parallel.

3. The overcurrent protection circuit of the three-way staggered parallel BOOST circuit according to claim 2 is characterized in that: The first drive circuit, the second drive circuit and the third drive circuit have the same structure, and include a chip D1, a resistor R3, a capacitor C1, a capacitor C3, a capacitor C5, a capacitor C2, a capacitor C4, a capacitor C6, a resistor R2, a resistor R4, a resistor R5 and a diode VD5. The first pin of the chip D1 is respectively connected to one end of the resistor R3 and one end of the capacitor C5, the second pin of the chip D1 is connected to one end of the capacitor C3, the fourth pin of the chip D1 is connected to one end of the capacitor C1, and the fifth pin of the chip D1 is respectively connected to one end of the capacitor C4, the capacitor C 6 and the power supply VCC+20V, the 6th pin of the chip D1 is connected to one end of the capacitor C2, the 8th pin of the chip D1 is respectively connected to the other end of the capacitor C2, one end of the resistor R2, and one end of the resistor R4, the other end of the resistor R4 is connected to the cathode of the diode VD5, the other end of the resistor R2 and the anode of the diode VD5 are respectively connected to one end of the resistor R5, the 7th pin of the chip D1, the other end of the capacitor C3, the other end of the capacitor C5, the other end of the capacitor C4, the other end of the capacitor C6 and the other end of the resistor R5 are grounded respectively.

4. The overcurrent protection circuit of the three-way staggered parallel BOOST circuit according to any one of claims 1 to 3, characterized in that: The output end of the current sampling and amplifying circuit outputs a power frequency current signal and a high frequency current signal respectively.

5. The overcurrent protection circuit of the three-way staggered parallel BOOST circuit according to claim 4, characterized in that: The current sampling amplifier circuit includes a chip D4, a resistor R16, a resistor R17, a capacitor C23, a capacitor C24, a diode VD10, a capacitor C22, a resistor R19, a capacitor C21, a resistor R18, a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R25, a resistor R26 and a capacitor C26. The first pin of the chip D4 is respectively connected to one end of the capacitor C12, one end of the resistor R19 and one end of the resistor R17. The other end of the resistor R17 is respectively connected to the third pin of the diode VD10, one end of the capacitor C24 and one end of the resistor R16. The other end of the resistor R16 is respectively connected to one end of the capacitor C23 and the power frequency current signal. The second pin of the chip D4 is respectively connected to the first pin of the diode VD10, the other end of the capacitor C23 and the other end of the capacitor C24. The second pin of the diode VD10 is respectively connected to the second pin of the diode VD10. The pin is connected to the power supply VCC+3.3VA, the 3rd pin of the chip D1 is respectively connected to one end of the resistor R26, one end of the capacitor C27, one end of the resistor R18 and one end of the resistor R22, the other end of the resistor R18 is respectively connected to one end of the capacitor C20 and the power supply VCC+3.3VA, the 4th pin of the chip D4 is respectively connected to the other end of the resistor R19, the other end of the capacitor C21 and one end of the resistor R20, the other end of the resistor R20 is respectively connected to one end of the resistor R21 and one end of the capacitor C25, the other end of the resistor R22 is respectively connected to one end of the capacitor C26 and one end of the resistor R23, the other end of the capacitor C22, the other end of the capacitor C20, the other end of the capacitor C25, the other end of the capacitor C26, the other end of the capacitor C27, the other end of the resistor R26 and the other end of the resistor R25 are respectively grounded.

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