Overcurrent protection control circuit with multi-stage protection threshold adaptive variable speed response

Abstract

The invention discloses a multi-stage protection threshold self-adaptive variable-speed response over-current protection control circuit, and belongs to the technical field of current protection. Comprising a power supply enabling control relay circuit, a bus current acquisition circuit, a multistage threshold trigger circuit and a pulse transformer isolation circuit. The power supply enabling control relay circuit is used for receiving an enabling signal, controlling power supply of a post-stage circuit and further controlling reset and restart after over-current protection self-sustaining; the bus current acquisition circuit is used for acquiring bus current and sending a bus current sampling signal to the multi-stage threshold trigger circuit; the multi-stage threshold trigger circuit is used for receiving the bus current sampling signal and comparing the bus current sampling signal with an internal protection threshold voltage, and when the bus current sampling signal reaches the protection threshold voltage and lasts for a set time, a response pulse is triggered. According to the method, the overcurrent protection response time can be adaptively adjusted according to the bus overcurrent peak values in different intervals, so that the bus overcurrent problem under the complex load working condition of the power supply is comprehensively treated in different intervals.

Description

Technical Field

[0001] The present invention relates to the technical field of overcurrent protection, and in particular to an overcurrent protection control circuit with multi-level protection threshold adaptive speed response. Background Art

[0002] In the field of power electronics and automation control, overcurrent protection circuits are one of the core links to ensure safe and stable operation of the system, especially in working scenarios with complex power load conditions, instantaneous overcurrent on the input bus, and a wide overcurrent range. Although the traditional overcurrent protection circuit is relatively simple in structure, it usually consists of three parts: current detection circuit, overcurrent threshold comparison circuit, and judgment flip circuit. However, this type of circuit gradually reveals its limitations in the face of the increasing complexity and diversity of modern industrial and household equipment.

[0003] First of all, as the front end of the overcurrent protection circuit, the core function of the current detection circuit is to accurately convert the current signal in the circuit into a voltage value for further processing by the subsequent circuit. This conversion process is crucial to the accuracy and response speed of the protection circuit. However, under complex and changeable power load conditions, the current signal often exhibits nonlinear and dynamically changing characteristics. Traditional current detection circuits may not be able to capture these subtle current changes in a timely and accurate manner due to insufficient sampling accuracy or conversion delays, thereby affecting the overall performance of the protection circuit.

[0004] Secondly, the overcurrent threshold comparison circuit is responsible for comparing the voltage value output by the current detection circuit with the preset threshold value to determine whether the current flowing into the circuit exceeds the safe range. In traditional designs, this link usually adopts a single overcurrent protection threshold and response speed, that is, once the current exceeds the set threshold, regardless of its size, the same protection action will be triggered. However, in working scenarios where there is instantaneous overcurrent on the input bus and the overcurrent range is wide, this "one-size-fits-all" protection strategy is obviously not flexible and efficient enough. Instantaneous overcurrent may only be caused by short-term fluctuations in the load or external interference, rather than a real overload or short circuit. At this time, if a fixed threshold and response speed are still used for protection, it may cause malfunction of the protection circuit and affect the normal operation of the system.

[0005] Finally, the judgment flip circuit outputs a flip control signal according to the comparison result of the overcurrent threshold comparison circuit to cut off the power supply or take other protective measures. However, under complex working conditions, due to the insufficiency of the front-end detection and comparison links, the decision basis of the judgment flip circuit may not be sufficient or accurate, resulting in untimely or erroneous protection actions. In addition, the traditional overcurrent protection circuit also lacks the ability to adjust the protection response time according to the bus overcurrent peak value, which makes the protection circuit unable to provide the most optimized protection strategy when facing different types of overcurrent events.

[0006] In summary, the traditional overcurrent protection circuit has significant shortcomings when dealing with working scenarios with complex power load conditions, instantaneous overcurrent on the input bus and a wide overcurrent range, resulting in the overcurrent protection response time being unable to match the bus overcurrent peak for interval adjustment. Summary of the invention

[0007] Aiming at the problem in the prior art that the overcurrent protection response time cannot match the bus overcurrent peak value for zone adjustment when the power supply load condition is complex, the input bus has instantaneous overcurrent and the overcurrent range is wide, the present invention provides an overcurrent protection control circuit with multi-level protection threshold adaptive variable speed response, which can adaptively adjust the overcurrent protection response time according to the bus overcurrent peak value in different zones, thereby comprehensively managing the bus overcurrent problem under the power supply complex load condition.

[0008] In order to achieve the above object, the present invention provides the following technical solutions.

[0009] The present invention provides an overcurrent protection control circuit with a multi-level protection threshold adaptive speed response, comprising a power supply enable control relay circuit, a bus current acquisition circuit, a multi-level threshold trigger circuit, a pulse transformer isolation circuit, an overcurrent protection trigger and hold circuit, a MOS tube fast shutdown circuit and an N MOS tube switch group; the power supply enable control relay circuit is used to receive an enable signal, control the power supply of a subsequent circuit, and further control the reset and restart after the overcurrent protection is self-sustaining; the bus current acquisition circuit is used to perform bus current acquisition and send the bus current sampling signal to the multi-level threshold trigger circuit; the multi-level threshold trigger circuit is used to receive the bus current sampling signal and compare it with the internal protection threshold voltage, when the bus current sampling signal reaches the protection threshold voltage and lasts for a set time, trigger a response pulse to form an overcurrent protection response pulse signal; the pulse transformer isolation circuit is used to send the overcurrent protection response pulse signal generated by the multi-level threshold trigger circuit to the overcurrent protection trigger and hold circuit; the overcurrent protection trigger and hold circuit is used to receive the overcurrent protection pulse signal from the pulse transformer isolation circuit, drive the MOS tube fast shutdown circuit to complete the discharge of the gate-source voltage of the N MOS tube switch group, and shut down the N MOS tube switch group.

[0010] As a further improvement of the present invention, the N MOS switch group is connected to the bus return line, the power supply return line of the subsequent power supply circuit and the power supply positive line of the subsequent power supply circuit.

[0011] As a further improvement of the present invention, the N MOS tube switch group includes a capacitor C5, a voltage regulator tube Z2, a resistor R38, a resistor R39, an N MOS tube and a driving resistor; one end of the resistor R38 is connected to the positive power supply line Vin+ of the subsequent power supply circuit, the other end of the resistor R38 is connected to the cathode of the voltage regulator tube Z2, and the anode of the voltage regulator tube Z2 is connected to the bus return line VinGnd; the capacitor C5 and the resistor R39 are connected in parallel with the voltage regulator tube Z2; one end of the driving resistor is connected to the cathode of the voltage regulator tube Z2, the other end of the driving resistor is connected to the gate of the N MOS tube, the drain of the N MOS tube is connected to the power supply return line of the subsequent power supply circuit, and the source of the N MOS tube is connected to the bus return line VinGnd.

[0012] As a further improvement of the present invention, the multi-level threshold trigger circuit includes a protection comparison circuit; after several levels of the protection comparison circuits are combined, they are connected to a pulse transformer isolation circuit; the protection comparison circuit includes a capacitor, a diode, a comparator and a resistor; the number of the resistors is 4; the first resistor is connected to the inverting end of the comparator; one end of the capacitor is connected to the inverting end of the comparator, and the other end of the capacitor is connected to the first power supply ground Vgnd; one end of the second resistor is connected to the first power supply positive voltage Vcc+, and the other end of the second resistor is connected to the non-inverting end of the comparator; one end of the third resistor is connected to the non-inverting end of the comparator, and the other end of the third resistor is connected to the first power supply ground Vgnd; one end of the fourth resistor is connected to the first power supply positive voltage Vcc+, the other end of the fourth resistor is connected to the positive power supply end of the comparator, and the negative power supply end of the comparator is connected to the first power supply ground Vgnd; the output end of the comparator is connected to the cathode of the diode, and the anode of the diode is connected to the pulse transformer isolation circuit.

[0013] As a further improvement of the present invention, the pulse transformer isolation circuit includes a capacitor C4, a transistor V1, a pulse transformer T1, a diode D7, a resistor R21, a resistor R22, a resistor R23, a resistor R24 ​​and a resistor R25; one end of the resistor R21 is connected to a multi-level threshold trigger circuit; the base of the transistor V1 is connected to the other end of the resistor R21, the emitter of the transistor V1 is connected to the resistor R23, and the collector of the transistor V1 is connected to the pulse transformer T1; one end of the resistor R22 is connected to the The base of the transistor V1, the other end of the resistor R22 is connected to the emitter of the transistor V1; one end of the resistor R24 ​​is connected to the pulse transformer T1, and the other end of the resistor R24 ​​is connected to the first power supply ground Vgnd; one end of the resistor R25 is connected to the pulse transformer T1, and the other end of the resistor R25 is connected to the pulse transformer T1; the anode of the diode D7 is connected to the pulse transformer T1, the cathode of the diode D7 is connected to one end of the capacitor C4, and the other end of the capacitor C4 is connected to the pulse transformer T1.

[0014] As a further improvement of the present invention, the overcurrent protection trigger and holding circuit includes a diode D8, a comparator N3, a comparator N4, a resistor R26, a resistor R27, a resistor R28, a resistor R29, a resistor R30, a resistor R31 and a resistor R32; one end of the resistor R26 is connected to the cathode of the diode D8 and the in-phase end of the comparator N3, and the other end of the resistor R26 is connected to the pulse transformer T1 and the negative power supply end of the comparator N3; one end of the resistor R27 is connected to the inverting end of the comparator N3, and the other end of the resistor R27 is connected to the negative power supply end of the comparator N3; one end of the resistor R28 is connected to the inverting end of the comparator N3, and the other end of the resistor R28 is connected to the positive power supply end of the comparator N3; one end of the resistor R29 is connected to the output end of the comparator N3, and the other end of the resistor R29 is connected to the positive power supply end of the comparator N3; the anode of the diode D8 The cathode of the diode D8 is connected to the output end of the comparator N3, and the cathode of the diode D8 is connected to the non-inverting end of the comparator N3; the positive power supply end of the comparator N3 is connected to the second positive power supply voltage Vbh+, the negative power supply end of the comparator N3 is connected to the bus return line VinGnd, and the inverting end of the comparator N3 is also connected to the inverting end of the comparator N4; one end of the resistor R30 is connected to the output end of the comparator N3, and the other end of the resistor R30 is connected to the non-inverting end of the comparator N4; one end of the resistor R31 is connected to the output end of the comparator N4, and the other end of the resistor R31 is connected to the second positive power supply voltage Vbh+; one end of the resistor R32 is connected to the output end of the comparator N4, and the other end of the resistor R32 is connected to the MOS tube fast shutdown circuit; the positive power supply end of the comparator N4 is connected to the second positive power supply voltage Vbh+, and the negative power supply end of the comparator N4 is connected to the bus return line VinGnd.

[0015] As a further improvement of the present invention, the MOS tube fast shutdown circuit includes a transistor V2, a transistor V3, a resistor R33, a resistor R34, a resistor R35 and a resistor R36; the base of the transistor V2 is connected to the overcurrent protection trigger and holding circuit; one end of the resistor R33 is connected to the base of the transistor V2, and the other end of the resistor R33 is connected to the emitter of the transistor V2; one end of the resistor R34 is connected to the collector of the transistor V2, and the other end of the resistor R34 is connected to the base of the transistor V3; one end of the resistor R35 is connected to the base of the transistor V3, and the other end of the resistor R35 is connected to the emitter of the transistor V3; one end of the resistor R36 is connected to the emitter of the transistor V3, and the other end of the resistor R36 is connected to the N The gate-source supply voltage of the MOS switch group is Vgs+; the collector of the transistor V3 is connected to the bus return line VinGnd; the emitter of the transistor V2 is also connected to the bus return line VinGnd.

[0016] As a further improvement of the present invention, the power supply enable control relay circuit includes a capacitor C1, a diode D1, a diode D2, a diode D3, a diode D4, a voltage regulator Z1, a filter inductor L1, a filter inductor L2, a filter inductor L3, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11 and a resistor R12; one end of the resistor R1 is connected to the enable bus positive line, and the other end of the resistor R1 is connected to the relay J1; the cathode of the diode D1 is connected to the relay The anode of the diode D1 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the relay J1; the filter inductor L1 is connected in series with the resistor R3, and one end is connected to the relay J1, and the other end of the filter inductor L1 is connected in series with the resistor R3, and the first positive power supply voltage Vcc+ is connected; the filter inductor L2 is connected in series with the resistor R4, and one end is connected to the relay J1, and the other end of the filter inductor L2 is connected in series with the resistor R4, and the first negative power supply voltage Vcc- is connected; one end of the resistor R5 is connected to the positive line of the enabling bus, and the other end of the resistor R5 is connected to the relay J1. The cathode of the diode D2 is connected to the relay J1, the anode of the diode D2 is connected to one end of the resistor R6, and the other end of the resistor R6 is connected to the relay J1; one end of the resistor R7 is connected to the positive line of the enable bus, and the other end of the resistor R7 is connected to the relay J2; the cathode of the diode D3 is connected to the relay J2, the anode of the diode D3 is connected to one end of the resistor R8, and the other end of the resistor R8 is connected to the relay J2; one end of the filter inductor L3 is connected to the relay J2, and the other end of the filter inductor L3 is connected to the resistor R9. One end of the resistor R10 is connected to the enable bus positive line, the other end of the resistor R10 is connected to the relay J2, the cathode of the diode D4 is connected to the relay J2, the anode of the diode D4 is connected to one end of the resistor R11, and the other end of the resistor R11 is connected to the relay J2; the resistor R12, the capacitor C1 and the Zener diode Z1 are connected in parallel, the cathode of the Zener diode Z1 is connected to the second power supply positive voltage Vbh+, and the anode of the Zener diode Z1 is connected to the bus return line VinGnd.

[0017] As a further improvement of the present invention, one end of the bus current acquisition circuit is connected to the bus positive line; the other end of the bus current acquisition circuit is connected to the positive power supply line of the subsequent power supply circuit.

[0018] As a further improvement of the present invention, the bus current acquisition circuit includes a Hall current sensor and a resistor R37; one end of the resistor R37 is connected to the sampling output end of the Hall current sensor, and the other end of the resistor R37 is connected to the first power supply ground Vgnd; the positive power supply end of the Hall current sensor is connected to the first power supply positive voltage Vcc+, the negative power supply end of the Hall current sensor is connected to the first power supply negative voltage Vcc-, the power supply ground end of the Hall current sensor is connected to the first power supply ground Vgnd, the sampling output end of the Hall current sensor is connected to the bus current sampling signal IS, the measured current input end of the Hall current sensor is connected to the bus positive line, and the measured current output end of the Hall current sensor is connected to Vin+ of the positive power supply line of the subsequent power supply circuit.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention can adaptively adjust the response time of overcurrent protection according to different intervals of bus current (i.e., different levels of overcurrent peak value). This design enables the circuit to more accurately respond quickly and effectively to different levels of overcurrent conditions, thereby improving the protection efficiency and reliability of the power supply system. In particular, for the bus overcurrent problem under complex load conditions of the power supply, the present invention realizes comprehensive management between partitions. By setting a multi-level threshold, the circuit can more carefully identify and process overcurrent conditions in different ranges, avoiding the over-protection or under-protection problems that may be caused by the traditional single threshold protection method. Since the control circuit of the present invention can more accurately control the overcurrent protection response time and realize the partition management of different overcurrent conditions, the power density and reliability of the power supply can be significantly improved. This is conducive to reducing unnecessary energy loss and equipment damage while maintaining stable operation of the system. By optimizing the overcurrent protection strategy, the present invention reduces the dependence on high-power protection devices, thereby reducing the overall cost of the power supply system. Secondly, the design of the multi-level threshold enables the circuit to better adapt to different load conditions and bus current changes, thereby improving the adaptability and flexibility of the system. Through rapid and accurate overcurrent protection response, the present invention effectively reduces system failures and safety hazards caused by busbar overcurrent, and improves the overall stability and safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. In the drawings: Figure 1 The overall architecture of the overcurrent protection control circuit with multi-level protection threshold adaptive speed response of the present invention; Figure 2 The schematic diagram of the power supply enabling control relay circuit of the present invention; Figure 3It is a schematic diagram of the multi-level threshold trigger circuit, overcurrent protection trigger and holding circuit, pulse transformer isolation circuit and MOS tube fast shutdown circuit of the present invention; Figure 4 The figure is a schematic diagram of the bus current acquisition circuit and the N MOS tube switch group of the present invention. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0023] Aiming at the problem in the prior art that the power supply load condition is complex, the input bus has instantaneous overcurrent and the overcurrent range is wide, and the overcurrent protection response time cannot match the bus overcurrent peak value for zone adjustment. The present invention provides an overcurrent protection control circuit with multi-level protection threshold adaptive speed response, such as Figure 1 As shown, it includes a power supply enable control relay circuit, a bus current acquisition circuit, a multi-level threshold trigger circuit, a pulse transformer isolation circuit, an overcurrent protection trigger and holding circuit, a MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor, Metal-Oxide Semiconductor Field-Effect Transistor) fast shutdown circuit and an N MOS (N-Metal-Oxide-Semiconductor, N-type Metal-Oxide-Semiconductor) tube switch group.

[0024] The power supply enable control relay circuit, the multi-level threshold trigger circuit, the pulse transformer isolation circuit, the overcurrent protection trigger and hold circuit, the MOS tube fast shutdown circuit and the N MOS tube switch group are connected in sequence. The multi-level threshold trigger circuit is also connected to the bus current acquisition circuit. The overcurrent protection trigger and hold circuit is also connected to the power supply enable control relay circuit.

[0025] The input side of the power supply enable control relay circuit is connected to the enable bus positive line, the enable signal, the auxiliary source power supply positive terminal, the auxiliary source power supply negative terminal and the positive power supply line of the subsequent power supply circuit; the output side of the power supply enable control relay circuit is connected to the bus current acquisition circuit, the multi-level threshold trigger circuit and the power supply input terminal of the overcurrent protection trigger and holding circuit.

[0026] The bus current acquisition circuit is arranged on the bus positive line, one end of which is connected to the bus positive line, and the other end is connected to the power supply positive line of the subsequent power supply circuit.

[0027] The N MOS tube switch group is arranged on the bus return line, one end of which is connected to the bus return line and also connected to the power supply return line of the subsequent power supply circuit, and the other end is also connected to the power supply positive line of the subsequent power supply circuit.

[0028] like Figure 1 As shown, the present invention is an overcurrent protection control circuit with multi-level protection threshold adaptive speed response, wherein the functions of each component are as follows: The power supply enable control relay circuit receives an enable signal from the outside, controls the power supply of the subsequent circuit, and further controls the reset and restart after the overcurrent protection is self-sustaining.

[0029] The bus current acquisition circuit uses a Hall current sensor to collect the bus current and sends the bus current sampling signal to a multi-level threshold trigger circuit.

[0030] The multi-level threshold trigger circuit is composed of a multi-level comparison circuit. The protection threshold and overcurrent protection response time of each comparison circuit can be adjusted. When bus overcurrent occurs, the comparison circuit receives the bus current sampling signal and compares it with the internal protection threshold voltage. When the bus current sampling signal reaches the protection threshold voltage and lasts for a period of time, the multi-level comparison circuit adaptively triggers the response pulse and transmits the pulse signal to the overcurrent protection trigger and holding circuit through the pulse transformer isolation circuit.

[0031] The pulse transformer isolation circuit transmits the overcurrent protection response pulse to achieve ground isolation between the auxiliary source power supply and the busbar.

[0032] The overcurrent protection trigger and hold circuit receives the overcurrent protection pulse signal from the pulse transformer isolation circuit, triggers the overcurrent protection and holds itself, outputs a high level, drives the subsequent MOS tube fast shutdown circuit to quickly complete the discharge of the gate-source voltage of the N MOS tube switch group, thereby shutting down the N MOS tube switch group.

[0033] The MOS tube fast shutdown circuit receives the driving signal from the overcurrent protection trigger and holding circuit. When the driving signal is at a high level, the transistor inside the circuit is turned on, and the gate-source voltage of the N MOS tube switch group is quickly discharged to achieve fast shutdown of the NMOS tube switch group; when the driving signal is at a low level, the transistor is turned off, and the MOS tube driving voltage returns to a high level.

[0034] The N MOS switch group is composed of multiple N MOS tubes and their driving resistors, voltage regulator tubes and gate-source capacitors. It obtains the gate-source supply voltage from the bus through a voltage divider circuit, and receives overcurrent protection discharge control from the MOS tube fast shutdown circuit to achieve power supply startup surge current suppression and bus overcurrent protection shutdown and restart functions.

[0035] like Figure 2 As shown, the specific structure and working principle of the power supply enable control relay circuit are as follows: The power supply enable control relay circuit includes a capacitor C1, a diode D1, a diode D2, a diode D3, a diode D4, a voltage regulator Z1, a filter inductor L1, a filter inductor L2, a filter inductor L3, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11 and a resistor R12.

[0036] One end of the resistor R1 is connected to the positive line of the enable bus, and the other end of the resistor R1 is connected to one end of the first coil of the relay J1. The cathode of the diode D1 is also connected to one end of the first coil of the relay J1, and the anode of the diode D1 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the other end of the first coil of the relay J1, that is, the external enable signal "power off". After the filter inductor L1 is connected in series with the resistor R3, one end is connected to the contact of the relay J1, and the other end is connected to the first positive power supply voltage Vcc+. After the filter inductor L2 is connected in series with the resistor R4, one end is connected to the contact of the relay J1, and the other end is connected to the first negative power supply voltage Vcc-. One end of the resistor R5 is connected to the positive line of the enable bus, and the other end of the resistor R5 is connected to one end of the second coil of the relay J1. The cathode of the diode D2 is connected to one end of the second coil of the relay J1, and the anode of the diode D2 is connected to one end of the resistor R6, and the other end of the resistor R6 is connected to the other end of the second coil of the relay J1, that is, the external enable signal "power on". One end of the resistor R7 is connected to the positive line of the enable bus, and the other end of the resistor R7 is connected to one end of the first coil of the relay J2. The cathode of the diode D3 is connected to one end of the first coil of the relay J2, the anode of the diode D3 is connected to one end of the resistor R8, and the other end of the resistor R8 is connected to the other end of the first coil of the relay J2, that is, the external enable signal "power off". One end of the filter inductor L3 is connected to the contact of the relay J2, the other end of the filter inductor L3 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the second power supply positive voltage Vbh+. One end of the resistor R10 is connected to the positive line of the enable bus, and the other end of the resistor R10 is connected to one end of the second coil of the relay J2. The cathode of the diode D4 is connected to one end of the second coil of the relay J2, the anode of the diode D4 is connected to one end of the resistor R11, and the other end of the resistor R11 is connected to the other end of the second coil of the relay J2, that is, the external enable signal "power on". The resistor R12, the capacitor C1 and the voltage regulator Z1 are connected in parallel, the cathode of the voltage regulator Z1 is connected to the second positive power supply voltage Vbh+, and the anode of the voltage regulator Z1 is connected to the bus return line VinGnd.

[0037] Working principle of the power supply enable control relay circuit: Relay J1 and relay J2 in the power supply enable control relay circuit are both magnetic latching relays, and the initial state is the contact disconnected state. When the external enable signal "power on" has a low-level pulse signal, the internal contact of relay J1 is closed, and the auxiliary source power supply positive terminal and the auxiliary source power supply negative terminal supply power to the subsequent circuit. When the external enable signal "power off" has a low-level pulse signal, the internal contact of relay J1 is disconnected, and the auxiliary source power supply positive terminal and the auxiliary source power supply negative terminal stop supplying power to the subsequent circuit. Resistor R1 is the voltage-dividing and current-limiting resistor of the first coil of relay J1. Resistor R5 is the voltage-dividing and current-limiting resistor of the second coil of relay J1. Diode D1 and resistor R2 constitute a reverse elimination circuit to eliminate the back electromotive force generated by the first coil of relay J1 when the module external enable signal "power off" changes from a low level to a high level. Diode D2 and resistor R6 constitute a reverse elimination circuit to eliminate the back electromotive force generated by the second coil of relay J1 when the module external enable signal "power on" changes from a low level to a high level. The filter inductor L1 and the resistor R3 are connected in series to form an LR low-pass filter, which is used to suppress the current spike generated when the relay J1 contacts are closed, and filter out the high-frequency differential mode interference on the first power supply positive voltage Vcc+ line during the operation of the power system. The resistor R3 also has the function of overcurrent protection. The filter inductor L2 and the resistor R4 are connected in series to form an LR low-pass filter, which is used to suppress the current spike generated when the relay J1 contacts are closed, and filter out the high-frequency differential mode interference on the first power supply negative voltage Vcc- line during the operation of the power system. The resistor R4 also has the function of overcurrent protection.

[0038] When a low-level pulse signal appears in the external enable signal "power on", the internal contact of relay J2 is closed, and the positive power supply line Vin+ of the subsequent power supply circuit supplies power to the overcurrent protection trigger and holding circuit. When a low-level pulse signal appears in the external enable signal "power off", the internal contact of relay J2 is disconnected, and the positive power supply line Vin+ of the subsequent power supply circuit stops supplying power to the overcurrent protection trigger and holding circuit. Resistor R7 is the voltage-dividing and current-limiting resistor of the first coil of relay J2. Resistor R10 is the voltage-dividing and current-limiting resistor of the second coil of relay J2. Diode D3 and resistor R8 constitute a reverse elimination circuit to eliminate the back electromotive force generated by the first coil of relay J2 when the external enable signal "power off" of the module changes from a low level to a high level. Diode D4 and resistor R11 constitute a reverse elimination circuit to eliminate the back electromotive force generated by the second coil of relay J2 when the external enable signal "power on" of the module changes from a low level to a high level. The filter inductor L3, the resistor R9 and the capacitor C1 form an LRC low-pass filter to suppress the current spike generated when the relay J2 contacts are closed, and filter out the high-frequency differential mode interference on the positive line Vin+ of the power supply circuit of the subsequent power supply system during operation. The resistor R9 also has the function of overcurrent protection. The resistor R9 and the resistor R12 divide the voltage to obtain the second positive power supply voltage Vbh+, and the voltage regulator Z1 is used to stabilize the voltage.

[0039] like Figure 3 As shown, the core control circuit of the present invention includes a multi-level threshold trigger circuit, a pulse transformer isolation circuit, an overcurrent protection trigger and holding circuit and a MOS tube fast shutdown circuit.

[0040] The multi-level threshold trigger circuit is composed of N-level protection comparison circuits, and the structure and working principle of the single-level protection comparison circuit are similar.

[0041] The protection comparison circuit includes a capacitor, a diode, a comparator and a resistor, wherein the number of the resistors is 4.

[0042] One end of the first resistor is connected to the bus current sampling signal, and the other end of the first resistor is connected to the inverting end of the comparator; one end of the capacitor is connected to the inverting end of the comparator, and the other end of the capacitor is connected to the first power supply ground Vgnd. One end of the second resistor is connected to the first power supply positive voltage Vcc+, and the other end of the second resistor is connected to the non-inverting end of the comparator. One end of the third resistor is connected to the non-inverting end of the comparator, and the other end of the third resistor is connected to the first power supply ground Vgnd. One end of the fourth resistor is connected to the first power supply positive voltage Vcc+, and the other end of the fourth resistor is connected to the positive power supply end of the comparator, and the negative power supply end of the comparator is connected to the first power supply ground Vgnd. The output end of the comparator is connected to the cathode of the diode, and the anode of the diode is connected to the pulse transformer isolation circuit.

[0043] The structure and working principle of the single-stage protection comparison circuit are similar, so this specification takes the first-stage protection comparison circuit and the second-stage protection comparison circuit as examples to describe their specific structure and working principle in detail.

[0044] The first level protection comparison circuit includes a capacitor C2, a diode D5, a comparator N1, a resistor R13, a resistor R14, a resistor R15 and a resistor R16.

[0045] One end of the resistor R13 is connected to the bus current sampling signal IS, and the other end of the resistor R13 is connected to the inverting end of the comparator N1. One end of the capacitor C2 is connected to the inverting end of the comparator N1, and the other end of the capacitor C2 is connected to the first power supply ground Vgnd. One end of the resistor R14 is connected to the first power supply positive voltage Vcc+, and the other end of the resistor R14 is connected to the non-inverting end of the comparator N1. One end of the resistor R15 is connected to the non-inverting end of the comparator N1, and the other end of the resistor R15 is connected to the first power supply ground Vgnd. One end of the resistor R16 is connected to the first power supply positive voltage Vcc+, and the other end of the resistor R16 is connected to the positive power supply end of the comparator N1, and the negative power supply end of the comparator N1 is connected to the first power supply ground Vgnd. The output end of the comparator N1 is connected to the cathode of the diode D5, and the anode of the diode D5 is connected to one end of the resistor R21 after being combined with the anode of the output combining diode of the other protection comparison circuit.

[0046] The secondary protection comparison circuit includes a capacitor C3, a diode D6, a comparator N2, a resistor R17, a resistor R18, a resistor R19 and a resistor R20.

[0047] One end of the resistor R17 is connected to the bus current sampling signal IS, and the other end of the resistor R17 is connected to the inverting end of the comparator N2. One end of the capacitor C3 is connected to the inverting end of the comparator N2, and the other end of the capacitor C3 is connected to the first power supply ground Vgnd. One end of the resistor R18 is connected to the first power supply positive voltage Vcc+, and the other end of the resistor R18 is connected to the non-inverting end of the comparator N2. One end of the resistor R19 is connected to the non-inverting end of the comparator N2, and the other end of the resistor R19 is connected to the first power supply ground Vgnd. One end of the resistor R20 is connected to the first power supply positive voltage Vcc+, and the other end of the resistor R20 is connected to the positive power supply end of the comparator N2, and the negative power supply end of the comparator N2 is connected to the first power supply ground Vgnd. The output end of the comparator N2 is connected to the cathode of the diode D6, and the anode of the diode D6 is connected to one end of the resistor R21 after being combined with the anode of the output combining diode of the other protection comparison circuit.

[0048] The structure of the N-level protection comparison circuit is the same as that of the first-level protection comparison circuit and the second-level protection comparison circuit.

[0049] The working principle of the multi-level threshold trigger circuit: the protection threshold and the corresponding protection response time are set in each level of the protection comparison circuit. In principle, the lower protection threshold matches the longer protection response time, and the protection threshold increases step by step, and the protection response time decreases step by step. Now we analyze it based on the first-level protection comparison circuit and the second-level protection comparison circuit. In the first-level protection comparison circuit, resistors R14 and R15 are the first-level overcurrent protection threshold voltage-dividing resistors. By adjusting the ratio of the two, the first-level protection threshold can be adjusted; resistor R13 and capacitor C2 constitute the first-level overcurrent protection response delay circuit, and the first-level overcurrent protection response time can be adjusted by adjusting the resistance and capacitance parameters. In the second-level protection comparison circuit, resistors R18 and R19 are the second-level overcurrent protection threshold voltage-dividing resistors. By adjusting the ratio of the two, the second-level protection threshold can be adjusted; resistor R17 and capacitor C3 constitute the second-level overcurrent protection response delay circuit, and the second-level overcurrent protection response time can be adjusted by adjusting the resistance and capacitance parameters. During operation, both the primary protection comparison circuit and the secondary protection comparison circuit receive the bus current sampling signal IS and compare it with the internal protection threshold voltage. When the bus overcurrent amplitude is within the range from the primary protection threshold to the secondary protection threshold, the secondary protection comparison circuit cannot trigger the flip due to the high protection threshold of the secondary protection comparison circuit, and its comparator N2 maintains a high level output. At this time, the output of the comparator N1 in the primary protection comparison circuit is converted from a high level to a low level, the diode D5 is forward-conducted, the transistor V1 is driven to turn on, and the primary side of the pulse transformer generates a response pulse. Therefore, the protection response time at this time is controlled by the primary protection comparison circuit. When the bus overcurrent amplitude is within the range from the secondary protection threshold to the tertiary protection threshold, the protection response time of the primary protection comparison circuit is long, while the protection response time of the secondary protection comparison circuit is short. Therefore, the comparator N2 in the secondary protection comparison circuit completes the flip faster, and its output is converted from a high level to a low level. The diode D6 is forward-conducted, the transistor V1 is driven to turn on, and the primary side of the pulse transformer generates a response pulse. Therefore, the protection response time at this time is controlled by the secondary protection comparison circuit. This can be deduced to the N-level protection comparison circuit.

[0050] The pulse transformer isolation circuit includes a capacitor C4, a transistor V1, a pulse transformer T1, a diode D7, a resistor R21, a resistor R22, a resistor R23, a resistor R24 ​​and a resistor R25.

[0051] The base of transistor V1 is connected to the other end of resistor R21, the emitter of transistor V1 is connected to one end of resistor R23, the collector of transistor V1 is connected to pin 1 of pulse transformer T1, and the other end of resistor R23 is connected to the first positive power supply voltage Vcc+. One end of resistor R22 is connected to the base of transistor V1, and the other end of resistor R22 is connected to the emitter of transistor V1. One end of resistor R24 ​​is connected to pin 2 of pulse transformer T1, and the other end of resistor R24 ​​is connected to the first power supply ground Vgnd. One end of resistor R25 is connected to pin 3 of pulse transformer T1, and the other end of resistor R25 is connected to pin 4 of pulse transformer T1. The anode of diode D7 is connected to pin 3 of pulse transformer T1, the cathode of diode D7 is connected to one end of capacitor C4, and the other end of capacitor C4 is connected to pin 4 of pulse transformer T1. Pins 1 and 3 of pulse transformer T1 are the same-named terminals, and pins 2 and 4 are the same-named terminals. Pin 4 of pulse transformer T1 is connected to the bus return line VinGnd.

[0052] The transistor V1 is a PNP transistor.

[0053] Working principle of pulse transformer isolation circuit: When the output of any comparator in the multi-level threshold trigger circuit is converted from high level to low level, the diode connected to the comparator output is forward-conducted, driving transistor V1 to turn on, and the primary side of the pulse transformer T1 generates a response pulse, which is transmitted to the overcurrent protection trigger and holding circuit.

[0054] The over-current protection triggering and holding circuit includes a diode D8, a comparator N3, a comparator N4, a resistor R26, a resistor R27, a resistor R28, a resistor R29, a resistor R30, a resistor R31 and a resistor R32.

[0055] One end of the resistor R26 is connected to the cathode of the diode D8, and one end of the resistor R26 is also connected to the non-inverting end of the comparator N3 and the cathode of the diode D7; the other end of the resistor R26 is connected to the 4th pin of the pulse transformer T1, and the other end of the resistor R26 is also connected to the negative power supply end of the comparator N3. One end of the resistor R27 is connected to the inverting end of the comparator N3, and the other end of the resistor R27 is connected to the negative power supply end of the comparator N3. One end of the resistor R28 is connected to the inverting end of the comparator N3, and the other end of the resistor R28 is connected to the positive power supply end of the comparator N3. One end of the resistor R29 is connected to the output end of the comparator N3, and the other end of the resistor R29 is connected to the positive power supply end of the comparator N3. The anode of the diode D8 is connected to the output end of the comparator N3, and the cathode of the diode D8 is connected to the non-inverting end of the comparator N3. The positive power supply terminal of the comparator N3 is connected to the second positive power supply voltage Vbh+, the negative power supply terminal of the comparator N3 is connected to the bus return line VinGnd, and the inverting terminal of the comparator N3 is also connected to the inverting terminal of the comparator N4. One end of the resistor R30 is connected to the output end of the comparator N3, and the other end of the resistor R30 is connected to the non-inverting end of the comparator N4. One end of the resistor R31 is connected to the output end of the comparator N4, and the other end of the resistor R31 is connected to the second positive power supply voltage Vbh+. One end of the resistor R32 is connected to the output end of the comparator N4, and the other end of the resistor R32 is connected to the base of the triode V2. The positive power supply terminal of the comparator N4 is connected to the second positive power supply voltage Vbh+, and the negative power supply terminal of the comparator N4 is connected to the bus return line VinGnd.

[0056] Working principle of the overcurrent protection triggering and holding circuit: When a bus overcurrent fault occurs, after the overcurrent protection triggering and holding circuit receives a pulse signal, the output of comparator N3 and comparator N4 is converted from a low level to a high level, and the high level output is maintained to drive transistor V2 to turn on; when the overcurrent fault is eliminated, the relay in the power supply enable control relay circuit is turned off and then turned on again, the core control circuit is reset, and the output of comparator N3 and comparator N4 returns to a low level.

[0057] The MOS tube fast shutdown circuit includes a transistor V2, a transistor V3, a resistor R33, a resistor R34, a resistor R35 and a resistor R36.

[0058] The base of transistor V2 is connected to the other end of resistor R32. One end of resistor R33 is connected to the base of transistor V2, and the other end of resistor R33 is connected to the emitter of transistor V2, that is, bus return line VinGnd. One end of resistor R34 is connected to the collector of transistor V2, and the other end of resistor R34 is connected to the base of transistor V3. One end of resistor R35 is connected to the base of transistor V3, and the other end of resistor R35 is connected to the emitter of transistor V3. One end of resistor R36 is connected to the emitter of transistor V3, and the other end of resistor R36 is connected to the gate-source supply voltage Vgs+ of the N MOS switch group. The collector of transistor V3 is connected to the bus return line VinGnd.

[0059] Transistor V2 is an NPN transistor; transistor V3 is a PNP transistor.

[0060] Working principle of MOS tube fast shutdown circuit: When bus overcurrent fault occurs, comparator N4 in the overcurrent protection trigger and holding circuit outputs and maintains a high-level signal, driving transistor V2 to turn on, and then driving transistor V3 to turn on. The output drive current of comparator N4 is increased to several hundred times the original through the two-stage transistor current amplifier circuit, thereby achieving the purpose of fast discharge of gate-source voltage of N MOS tube switch group and fast shutdown of N MOS tube. When the overcurrent fault is eliminated, the relay in the power supply enable control relay circuit is turned off and then turned on again, the core control circuit is reset, the output end of comparator N4 returns to a low level, transistors V2 and V3 are in the off state, and the N MOS tube switch group is turned on. The MOS tube fast shutdown circuit can avoid the problem that the N MOS tube shutdown time is too long to affect the overcurrent protection response time, and at the same time avoid the problem that the NMOS tube is in the linear working area for a long time during the shutdown process under the bus overcurrent state, ensuring the working reliability of the N MOS tube.

[0061] like Figure 4 As shown, the specific structure and working principle of the bus current acquisition circuit and the N MOS tube switch group are as follows: The bus current acquisition circuit includes a Hall current sensor and a resistor R37.

[0062] One end of the resistor R37 is connected to the sampling output end of the Hall current sensor, and the other end of the resistor R37 is connected to the first power supply ground Vgnd. The positive power supply end of the Hall current sensor is connected to the first power supply positive voltage Vcc+, the negative power supply end of the Hall current sensor is connected to the first power supply negative voltage Vcc-, the power supply ground end of the Hall current sensor is connected to the first power supply ground Vgnd, the sampling output end of the Hall current sensor is connected to the bus current sampling signal IS, the measured current input end of the Hall current sensor is connected to the bus positive line, and the measured current output end of the Hall current sensor is connected to Vin+ of the positive power supply line of the subsequent power supply circuit.

[0063] Working principle of the bus current acquisition circuit: The bus current acquisition circuit acquires the bus current at the bus positive line port and sends the bus current sampling signal to the multi-level threshold trigger circuit.

[0064] The N MOS switch group includes a capacitor C5, a voltage regulator Z2, a resistor R38, a resistor R39, an N MOS tube and a driving resistor.

[0065] One end of the resistor R38 is connected to the positive power supply line Vin+ of the subsequent power supply circuit, and the other end of the resistor R38 is connected to the cathode of the voltage regulator tube Z2, and the anode of the voltage regulator tube Z2 is connected to the bus return line VinGnd. Capacitor C5 and resistor R39 are connected in parallel with the voltage regulator tube Z2.

[0066] There are n groups of N MOS tubes and driving resistors in parallel in the N MOS tube switch group, where the driving resistor One end is connected to the cathode of the voltage regulator tube Z2, driving the resistor The other end is connected to the N MOS tube The gate of the drive resistor One end is connected to the cathode of the voltage regulator tube Z2, driving the resistor The other end is connected to the N MOS tube The gate of the drive resistor One end is connected to the cathode of the voltage regulator tube Z2, driving the resistor The other end is connected to the N MOS tube Gate drive resistor One end is connected to the cathode of the voltage regulator tube Z2, driving the resistor The other end is connected to the N MOS tube The source of all N MOS tubes is connected to the bus return line VinGnd, and the drain of all N MOS tubes is connected to the power supply return line of the subsequent power supply circuit.

[0067] Working principle of N MOS switch group: The busbar is divided by resistors R38 and R39 to obtain the gate-source supply voltage Vgs+ of the N MOS switch group, and the voltage regulator Z2 is used for voltage stabilization. The N MOS switch group has the functions of power supply startup surge current suppression and busbar overcurrent protection shutdown and restart. When a busbar overcurrent fault occurs, the transistors V2 and V3 in the MOS fast shutdown circuit are turned on, the gate-source voltage of the N MOS switch group is quickly discharged, and the N MOS tube is quickly turned off, thereby protecting the subsequent power supply circuit. When the overcurrent fault is eliminated, the relay in the power supply enable control relay circuit is turned off and then turned on again, the core control circuit is reset, the transistors V2 and V3 in the MOS fast shutdown circuit are in the off state, the NMOS switch group is turned on, and the subsequent power supply circuit resumes normal operation. By adjusting the number of N MOS tubes and their driving resistors, the busbar current working requirements can be met, and by adjusting the gate-source capacitance, the power supply startup surge current suppression requirements can be met.

[0068] To summarize, the present invention is composed of several functional circuits, including a power supply enable control relay circuit, a bus current acquisition circuit, a multi-level threshold trigger circuit, a pulse transformer isolation circuit, an overcurrent protection trigger and holding circuit, a MOS tube fast shutdown circuit and an N MOS tube switch group. The overcurrent protection response time can be adaptively adjusted according to the bus overcurrent peak value in different intervals, thereby comprehensively managing the bus overcurrent problem under complex load conditions of the power supply in different intervals, meeting the use requirements under complex conditions, improving the power density and reliability of the power supply, reducing the number of high-power devices used, and reducing the power supply cost.

[0069] Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the preceding claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a disclaimer of such subject matter, nor should it be considered that the applicants did not consider such subject matter to be part of the disclosed inventive subject matter.

[0070] The above content is a further detailed description of the present invention. It cannot be determined that the specific implementation methods of the present invention are limited to these. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, they can also make several simple deductions or substitutions, which should be regarded as belonging to the protection scope of the present invention determined by the submitted claims.

Claims

1. An overcurrent protection control circuit with multi-level protection threshold adaptive speed response, characterized in that: It includes a power supply enabling control relay circuit, a bus current acquisition circuit, a multi-level threshold trigger circuit, a pulse transformer isolation circuit, an overcurrent protection trigger and holding circuit, a MOS tube fast shutdown circuit and an N MOS tube switch group; The power supply enable control relay circuit is used to receive an enable signal, control the power supply of the subsequent circuit, and further control the reset and restart of the overcurrent protection after self-sustaining; The bus current acquisition circuit is used to acquire bus current and send the bus current sampling signal to the multi-level threshold trigger circuit; The multi-level threshold trigger circuit is used to receive the bus current sampling signal and compare it with the internal protection threshold voltage. When the bus current sampling signal reaches the protection threshold voltage and lasts for a set time, a response pulse is triggered to form an overcurrent protection response pulse signal; The pulse transformer isolation circuit is used to send the overcurrent protection response pulse signal generated by the multi-level threshold trigger circuit to the overcurrent protection trigger and hold circuit; The overcurrent protection trigger and holding circuit is used to receive the overcurrent protection pulse signal from the pulse transformer isolation circuit, drive the MOS tube fast shutdown circuit to complete the discharge of the gate-source voltage of the N MOS tube switch group, and shut down the N MOS tube switch group.

2. The overcurrent protection control circuit with multi-level protection threshold adaptive speed response according to claim 1, characterized in that: The NMOS switch group is connected to the bus return line, the power supply return line of the subsequent power supply circuit and the power supply positive line of the subsequent power supply circuit.

3. The overcurrent protection control circuit with multi-level protection threshold adaptive speed response according to claim 2, characterized in that: The N MOS switch group includes a capacitor C5, a voltage regulator Z2, a resistor R38, a resistor R39, an N MOS tube and a driving resistor; One end of the resistor R38 is connected to the positive power supply line Vin+ of the subsequent power supply circuit, the other end of the resistor R38 is connected to the cathode of the voltage regulator tube Z2, and the anode of the voltage regulator tube Z2 is connected to the bus return line VinGnd; The capacitor C5 and the resistor R39 are connected in parallel with the voltage regulator tube Z2; One end of the driving resistor is connected to the cathode of the voltage regulator tube Z2, the other end of the driving resistor is connected to the gate of the N MOS tube, the drain of the N MOS tube is connected to the power supply return line of the subsequent power supply circuit, and the source of the N MOS tube is connected to the bus return line VinGnd.

4. The overcurrent protection control circuit with multi-level protection threshold adaptive speed response according to claim 1, characterized in that: The multi-level threshold trigger circuit includes a protection comparison circuit; After the protection comparison circuits of several stages are combined, they are connected to the pulse transformer isolation circuit; The protection comparison circuit includes a capacitor, a diode, a comparator and a resistor; The number of resistors is 4; The first resistor is connected to the inverting terminal of the comparator; one end of the capacitor is connected to the inverting terminal of the comparator, and the other end of the capacitor is connected to the first power supply ground Vgnd; One end of the second resistor is connected to the first positive power supply voltage Vcc+, and the other end of the second resistor is connected to the non-inverting terminal of the comparator; One end of the third resistor is connected to the non-inverting terminal of the comparator, and the other end of the third resistor is connected to the first power supply ground Vgnd; One end of the fourth resistor is connected to the first positive power supply voltage Vcc+, the other end of the fourth resistor is connected to the positive power supply terminal of the comparator, and the negative power supply terminal of the comparator is connected to the first power supply ground Vgnd; The output end of the comparator is connected to the cathode of the diode, and the anode of the diode is connected to the pulse transformer isolation circuit.

5. The overcurrent protection control circuit with multi-level protection threshold adaptive speed response according to claim 1, characterized in that: The pulse transformer isolation circuit includes a capacitor C4, a transistor V1, a pulse transformer T1, a diode D7, a resistor R21, a resistor R22, a resistor R23, a resistor R24 ​​and a resistor R25; One end of the resistor R21 is connected to a multi-level threshold trigger circuit; The base of the transistor V1 is connected to the other end of the resistor R21, the emitter of the transistor V1 is connected to the resistor R23, and the collector of the transistor V1 is connected to the pulse transformer T1; One end of the resistor R22 is connected to the base of the transistor V1, and the other end of the resistor R22 is connected to the emitter of the transistor V1; One end of the resistor R24 ​​is connected to the pulse transformer T1, and the other end of the resistor R24 ​​is connected to the first power supply ground Vgnd; One end of the resistor R25 is connected to the pulse transformer T1, and the other end of the resistor R25 is connected to the pulse transformer T1; The anode of the diode D7 is connected to the pulse transformer T1 , the cathode of the diode D7 is connected to one end of the capacitor C4 , and the other end of the capacitor C4 is connected to the pulse transformer T1 .

6. The overcurrent protection control circuit with multi-level protection threshold adaptive speed response according to claim 1, characterized in that: The overcurrent protection trigger and holding circuit includes a diode D8, a comparator N3, a comparator N4, a resistor R26, a resistor R27, a resistor R28, a resistor R29, a resistor R30, a resistor R31 and a resistor R32; One end of the resistor R26 is connected to the cathode of the diode D8 and the in-phase terminal of the comparator N3, and the other end of the resistor R26 is connected to the pulse transformer T1 and the negative power supply terminal of the comparator N3; One end of the resistor R27 is connected to the inverting end of the comparator N3, and the other end of the resistor R27 is connected to the negative power supply end of the comparator N3; One end of the resistor R28 is connected to the inverting end of the comparator N3, and the other end of the resistor R28 is connected to the positive power supply end of the comparator N3; One end of the resistor R29 is connected to the output end of the comparator N3, and the other end of the resistor R29 is connected to the positive power supply end of the comparator N3; The anode of the diode D8 is connected to the output terminal of the comparator N3, and the cathode of the diode D8 is connected to the non-inverting terminal of the comparator N3; The positive power supply terminal of the comparator N3 is connected to the second positive power supply voltage Vbh+, the negative power supply terminal of the comparator N3 is connected to the bus return line VinGnd, and the inverting terminal of the comparator N3 is also connected to the inverting terminal of the comparator N4; One end of the resistor R30 is connected to the output end of the comparator N3, and the other end of the resistor R30 is connected to the non-inverting end of the comparator N4; One end of the resistor R31 is connected to the output end of the comparator N4, and the other end of the resistor R31 is connected to the second positive power supply voltage Vbh+; One end of the resistor R32 is connected to the output end of the comparator N4, and the other end of the resistor R32 is connected to the MOS tube fast shutdown circuit; The positive power supply terminal of the comparator N4 is connected to the second positive power supply voltage Vbh+, and the negative power supply terminal of the comparator N4 is connected to the bus return line VinGnd.

7. The overcurrent protection control circuit with multi-level protection threshold adaptive speed response according to claim 1, characterized in that: The MOS tube fast shutdown circuit includes a transistor V2, a transistor V3, a resistor R33, a resistor R34, a resistor R35 and a resistor R36; The base of the transistor V2 is connected to an overcurrent protection trigger and holding circuit; One end of the resistor R33 is connected to the base of the transistor V2, and the other end of the resistor R33 is connected to the emitter of the transistor V2; One end of the resistor R34 is connected to the collector of the transistor V2, and the other end of the resistor R34 is connected to the base of the transistor V3; One end of the resistor R35 is connected to the base of the transistor V3, and the other end of the resistor R35 is connected to the emitter of the transistor V3; One end of the resistor R36 is connected to the emitter of the transistor V3, and the other end of the resistor R36 is connected to the gate-source supply voltage Vgs+ of the N MOS switch group; the collector of the transistor V3 is connected to the bus return line VinGnd; the emitter of the transistor V2 is also connected to the bus return line VinGnd.

8. The overcurrent protection control circuit with multi-level protection threshold adaptive speed response according to claim 1, characterized in that: The power supply enabling control relay circuit includes a capacitor C1, a diode D1, a diode D2, a diode D3, a diode D4, a voltage regulator Z1, a filter inductor L1, a filter inductor L2, a filter inductor L3, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11 and a resistor R12; One end of the resistor R1 is connected to the positive line of the enabling bus, and the other end of the resistor R1 is connected to the relay J1; the cathode of the diode D1 is connected to the relay J1, the anode of the diode D1 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the relay J1; One end of the filter inductor L1 connected in series with the resistor R3 is connected to the relay J1, and the other end of the filter inductor L1 connected in series with the resistor R3 is connected to the first positive power supply voltage Vcc+; One end of the filter inductor L2 and the resistor R4 connected in series is connected to the relay J1, and the other end of the filter inductor L2 and the resistor R4 connected in series is connected to the first negative power supply voltage Vcc-; One end of the resistor R5 is connected to the positive line of the enabling bus, and the other end of the resistor R5 is connected to the relay J1; the cathode of the diode D2 is connected to the relay J1, the anode of the diode D2 is connected to one end of the resistor R6, and the other end of the resistor R6 is connected to the relay J1; One end of the resistor R7 is connected to the positive line of the enabling bus, and the other end of the resistor R7 is connected to the relay J2; the cathode of the diode D3 is connected to the relay J2, the anode of the diode D3 is connected to one end of the resistor R8, and the other end of the resistor R8 is connected to the relay J2; One end of the filter inductor L3 is connected to the relay J2, the other end of the filter inductor L3 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the second positive power supply voltage Vbh+; One end of the resistor R10 is connected to the positive line of the enabling bus, the other end of the resistor R10 is connected to the relay J2, the cathode of the diode D4 is connected to the relay J2, the anode of the diode D4 is connected to one end of the resistor R11, and the other end of the resistor R11 is connected to the relay J2; The resistor R12, the capacitor C1 and the voltage regulator Z1 are connected in parallel, the cathode of the voltage regulator Z1 is connected to the second positive power supply voltage Vbh+, and the anode of the voltage regulator Z1 is connected to the bus return line VinGnd.

9. The overcurrent protection control circuit with multi-level protection threshold adaptive speed response according to claim 1, characterized in that: One end of the bus current collection circuit is connected to the bus positive line; The other end of the bus current acquisition circuit is connected to the positive power supply line of the subsequent power supply circuit.

10. The overcurrent protection control circuit with multi-level protection threshold adaptive speed response according to claim 9, characterized in that: The bus current acquisition circuit includes a Hall current sensor and a resistor R37; One end of the resistor R37 is connected to the sampling output end of the Hall current sensor, and the other end of the resistor R37 is connected to the first power supply ground Vgnd; The positive power supply terminal of the Hall current sensor is connected to the first positive power supply voltage Vcc+, the negative power supply terminal of the Hall current sensor is connected to the first negative power supply voltage Vcc-, the power ground terminal of the Hall current sensor is connected to the first power supply ground Vgnd, the sampling output terminal of the Hall current sensor is connected to the bus current sampling signal IS, the measured current input terminal of the Hall current sensor is connected to the bus positive line, and the measured current output terminal of the Hall current sensor is connected to Vin+ of the positive power supply line of the subsequent power supply circuit.

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