A short-circuit protection circuit based on the rate of change of inductor current

Abstract

The present invention discloses a short - circuit protection circuit based on the rate of change of inductor current, which relates to the technical field of short - circuit protection. It includes a power switch module for power transmission; a switch driving module for driving the power switch module; an inductor detection module for detecting the rate of change of inductor current and signal processing; a short - circuit protection module for short - circuit judgment; a desaturation detection module for voltage sampling, over - voltage judgment and power dissipation; a self - locking module for high - level self - locking; a primary detection module for voltage comparison and regulating the buck rate of the driving and regulating module; a secondary detection module for controlling the switch driving module to stop working when the input voltage is less than a set second voltage threshold; and a driving and regulating module for regulating the voltage of the output signal of the switch driving module. The short - circuit protection circuit based on the rate of change of inductor current of the present invention can avoid the impact voltage on the power switch module during short - circuit, and improve the safety of the power switch module.

Description

Technical Field

[0001] The present invention relates to the technical field of short - circuit protection, and particularly to a short - circuit protection circuit based on the rate of change of inductor current. Background Art

[0002] High - power IGBTs have been widely used in high - power variable - frequency applications such as rail transit, aerospace, new - energy power generation, industrial drive, and smart grid. For IGBTs, short - circuit is one of the most severe operating conditions. To avoid IGBT damage caused by short - circuit faults, in the prior art, IGBTs generally use the method of detecting the rate of change of inductor current to quickly detect short - circuits in IGBTs. When a short - circuit occurs, the IGBT is disconnected. However, when a short - circuit occurs in the IGBT, directly controlling the IGBT to cut off will cause the IGBT to experience a desaturation phenomenon, resulting in a large voltage across its collector and emitter, which directly leads to IGBT damage. Therefore, improvement is needed. Summary of the Invention

[0003] An embodiment of the present invention provides a short - circuit protection circuit based on the rate of change of inductor current to solve the problems raised in the above - mentioned background art.

[0004] According to an embodiment of the present invention, a short - circuit protection circuit based on the rate of change of inductor current is provided, including: a power - switch module, a switch - driving module, an inductor - detecting module, a short - circuit protection module, a desaturation - detecting module, a self - locking module, a primary - detecting module, a secondary - detecting module, and a driving - adjusting module;

[0005] The power - switch module is connected to the switch - driving module and is used to access working electrical energy and adjust the voltage of the working electrical energy input to the load when receiving a driving signal output by the switch - driving module;

[0006] The switch - driving module is connected to the secondary - detecting module and is used to provide a pulse signal, amplify the pulse signal, output a driving signal, and stop providing the pulse signal when receiving a first protection signal output by the secondary - detecting module;

[0007] The inductor - detecting module is connected to the power - switch module and is used to detect the rate of change of the current of the inductor of the power - switch module, clamp and divide the detected signal, and output a first detection signal;

[0008] The short - circuit protection module is connected to the inductor - detecting module and is used to filter the first detection signal and, when the filtered signal is greater than a set short - circuit threshold, self - lock and output a first control signal;

[0009] A desaturation detection module, connected to the power switch module, the secondary detection module, and the switch driving module, is configured to sample the voltage of the power switch module and output a first sampling signal. When the first sampling signal is greater than a set overvoltage threshold, it outputs a second control signal. When receiving the first protection signal output by the secondary detection module, it performs an electric energy discharge process on the power switch module;

[0010] A self-locking module, connected to the desaturation detection module, is configured to perform a high-level self-locking operation and output a third control signal when receiving the second control signal;

[0011] A primary detection module, connected to the self-locking module and the short-circuit protection module, is configured to receive the first sampling signal when receiving the third control signal or the first control signal, and when the first sampling signal is less than a set first voltage threshold, output a fourth control signal;

[0012] A secondary detection module, connected to the primary detection module, is configured to receive the first sampling signal when receiving the fourth control signal, and when the first sampling signal is less than a set second voltage threshold, output a first protection signal and perform a self-locking process on the first protection signal;

[0013] A drive adjustment module, connected to the switch driving module, the self-locking module, and the primary detection module, is configured to receive and store a pulse signal. When receiving the third control signal, it reduces the voltage of the pulse signal. When receiving the fourth control signal, it accelerates the rate of reducing the voltage of the pulse signal.

[0014] As a further solution of the present invention: The power switch module includes an input port, a first load, a first power switch, and a first inductor;

[0015] Preferably, the input port is connected to the collector of the first power switch through the first load. The gate of the first power switch is connected to the switch driving module. The emitter of the first power switch is connected to the first end of the first inductor, and the second end of the first inductor is grounded.

[0016] As a further solution of the present invention: The inductor detection module includes a second diode, a fifth resistor, a sixth resistor, a third diode, a seventh resistor, and an eighth resistor;

[0017] Preferably, the anode of the second diode is connected to the first end of the first inductor. The cathode of the second diode is connected to one end of the sixth resistor, the cathode of the third diode, and the first end of the eighth resistor through the fifth resistor. The second end of the eighth resistor is connected to the short-circuit protection module and is connected to the anode of the third diode, the other end of the sixth resistor, and the second end of the first inductor through the seventh resistor.

[0018] As a further aspect of the present invention: The switch driving module includes a first resistor, a first power supply, a first switching tube, a second switching tube, a second power supply, a second resistor, a first logic device, and a switch driving device;

[0019] Preferably, the emitter of the first switching tube is connected to the emitter of the second switching tube and is connected to the gate of the first power switch through the first resistor. The collector of the first switching tube is connected to the first power supply. The base of the first switching tube is connected to the base of the second switching tube and is connected to the Y terminal of the first logic device and the driving adjustment module through the second resistor. The B terminal of the first logic device is connected to the switch driving device. The A terminal of the first logic device is connected to the desaturation detection module and the secondary detection module. The collector of the second switching tube is connected to the second power supply.

[0020] As a further aspect of the present invention: The driving adjustment module includes a first diode, a first capacitor, a third resistor, a fourth resistor, a first MOS tube, an eighth diode, and a third switching tube;

[0021] Preferably, the anode of the first diode is connected to the Y terminal of the first logic device. The cathode of the first diode is connected to one end of the third resistor and one end of the fourth resistor and is connected to the second power supply and the emitter of the third switching tube through the first capacitor. The other end of the third resistor is connected to the drain of the first MOS tube. The source of the first MOS tube is connected to the anode of the eighth diode. The gate of the first MOS tube is connected to the other end of the fourth resistor and the primary detection module. The collector of the third switching tube is connected to the cathode of the eighth diode. The base of the third switching tube is connected to the self-locking module.

[0022] As a further aspect of the present invention: The desaturation detection module includes a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourth diode, a third capacitor, a second MOS tube, and a first inverter;

[0023] Preferably, one end of the tenth resistor is connected to the collector of the first power switch. The other end of the tenth resistor is connected to the first end of the twelfth resistor and is connected to the second end of the first inductor through the eleventh resistor. The second end of the twelfth resistor is connected to the primary detection module, the secondary detection module, the drain of the second MOS tube, and one end of the third capacitor and is connected to the cathode of the fourth diode through the thirteenth resistor. The anode of the fourth diode is connected to the self-locking module. The source of the second MOS tube is connected to the other end of the third capacitor and the ground terminal. The gate of the second MOS tube is connected to the output terminal of the first inverter. The input terminal of the first inverter is connected to the A terminal of the first logic device.

[0024] As a further aspect of the present invention: The self-locking module includes a fourteenth resistor, a third power supply, a fifth diode, a sixth diode, and a second logic device;

[0025] Preferably, the A terminal of the second logic device is connected to the third power supply through the fourteenth resistor. The B terminal of the second logic device is connected to the cathodes of the sixth diode and the fifth diode. The anode of the fifth diode is connected to the anode of the fourth diode. The anode of the sixth diode is connected to the Y terminal of the second logic device, the base of the third switching transistor, and the first-level detection module.

[0026] As a further aspect of the present invention: The first-level detection module includes a first thyristor, a fifteenth resistor, a first threshold device, and a second comparator.

[0027] Preferably, the anode of the first thyristor is connected to the second terminal of the twelfth resistor. The cathode of the first thyristor is connected to the inverting terminal of the second comparator and grounded through the fifteenth resistor. The non-inverting terminal of the second comparator is connected to the first threshold device. The control terminal of the first thyristor is connected to the Y terminal of the second logic device and the short-circuit protection module. The output terminal of the second comparator is connected to the gate of the first MOS transistor and the second-level detection module.

[0028] As a further aspect of the present invention: The second-level detection module includes a second thyristor, a sixteenth resistor, a second threshold device, a third comparator, a second flip-flop, and a second inverter.

[0029] Preferably, the anode of the second thyristor is connected to the second terminal of the twelfth resistor. The cathode of the second thyristor is connected to the inverting terminal of the third comparator and connected to the D terminal of the second flip-flop and the ground terminal through the sixteenth resistor. The output terminal of the third comparator is connected to the CLK terminal of the second flip-flop. The control terminal of the second thyristor is connected to the output terminal of the second comparator. The non-inverting terminal of the third comparator is connected to the second threshold device. The Q terminal of the second flip-flop is connected to the input terminal of the second inverter. The output terminal of the second inverter is connected to the A terminal of the first logic device.

[0030] As a further aspect of the present invention: The short-circuit protection module includes a ninth resistor, a second capacitor, a first comparator, a third threshold device, a first flip-flop, and a seventh diode.

[0031] Preferably, the non-inverting terminal of the first comparator is connected to one end of the ninth resistor and connected to the D terminal of the first flip-flop and the ground terminal through the second capacitor. The other end of the ninth resistor is connected to the second terminal of the eighth resistor. The inverting terminal of the first comparator is connected to the third threshold device. The Q terminal of the first flip-flop is connected to the anode of the seventh diode. The cathode of the seventh diode is connected to the control terminal of the first thyristor.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: The short-circuit protection circuit based on the rate of change of inductor current of the present invention can drive the power switch module to conduct by the switch driving module. The inductor detection module detects the rate of change of the inductor current of the power switch module and cooperates with the short-circuit protection module to judge short circuit. When a short circuit occurs, the self-locking module and the first-level detection module are triggered to work. The desaturation detection module detects the voltage conditions at the input and output ends of the power switch module and performs desaturation detection and overvoltage detection. When overvoltage occurs, the self-locking module controls the driving adjustment module and the first-level detection module to work self-locked, reducing the voltage of the signal output by the switch driving module. When the voltage of the power switch module is lower than the set first voltage threshold, the first-level detection module will control the driving adjustment module to increase the buck rate of the driving adjustment module. When the voltage of the power switch module is lower than the set second voltage threshold, the second-level detection module will control the switch driving module to stop driving, and the desaturation detection module will perform power dissipation processing on the power switch module, avoiding the impact of the impact voltage on the power switch module during short circuit and improving the safety of the power switch module. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 It is a schematic block diagram of the principle of a short-circuit protection circuit based on the rate of change of inductor current provided by an embodiment of the present invention.

[0035] Figure 2 It is a circuit diagram of a short-circuit protection circuit based on the rate of change of inductor current provided by an embodiment of the present invention.

[0036] Figure 3 It is a circuit diagram of the desaturation detection module provided by an embodiment of the present invention.

[0037] Figure 4 It is a circuit diagram of the self-locking module provided by an embodiment of the present invention.

[0038] Figure 5 It is a circuit diagram of the first-level detection module provided by an embodiment of the present invention.

[0039] Figure 6 It is a circuit diagram of the second-level detection module provided by an embodiment of the present invention.

[0040] Figure 7 It is a circuit diagram of the short-circuit protection module provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] Next, in combination with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0042] In one embodiment, please refer to Figure 1 , a short - circuit protection circuit based on the rate of change of inductor current, comprising: a power switch module 1, a switch driving module 2, an inductor detection module 3, a short - circuit protection module 4, a desaturation detection module 5, a self - locking module 6, a primary detection module 7, a secondary detection module 8, and a drive adjustment module 9;

[0043] Specifically, the power switch module 1 is connected to the switch driving module 2 and is used to access working electrical energy and adjust the voltage of the working electrical energy input to the load when receiving the driving signal output by the switch driving module 2.

[0044] The switch driving module 2 is connected to the secondary detection module 8 and is used to provide a pulse signal, amplify the pulse signal, output a driving signal, and stop providing the pulse signal when receiving the first protection signal output by the secondary detection module 8.

[0045] The inductor detection module 3 is connected to the power switch module 1 and is used to detect the rate of change of the current of the inductor of the power switch module 1, perform clamping and voltage - dividing processing on the detected signal, and output a first detection signal.

[0046] The short - circuit protection module 4 is connected to the inductor detection module 3 and is used to filter the first detection signal, and when the filtered signal is greater than the set short - circuit threshold, self - lock and output a first control signal.

[0047] The desaturation detection module 5 is connected to the power switch module 1, the secondary detection module 8, and the switch driving module 2 and is used to sample the voltage of the power switch module 1 and output a first sampling signal. When the first sampling signal is greater than the set over - voltage threshold, output a second control signal. When receiving the first protection signal output by the secondary detection module 8, perform electrical energy discharge processing on the power switch module 1.

[0048] The self - locking module 6 is connected to the desaturation detection module 5 and is used to perform high - level self - locking operation and output a third control signal when receiving the second control signal.

[0049] The first-level detection module 7, connected to the self-locking module 6 and the short-circuit protection module 4, is configured to receive the first sampling signal when receiving the third control signal or the first control signal, and output a fourth control signal when the first sampling signal is less than a set first voltage threshold;

[0050] The second-level detection module 8, connected to the first-level detection module 7, is configured to receive the first sampling signal when receiving the fourth control signal, and output a first protection signal and perform self-locking processing on the first protection signal when the first sampling signal is less than a set second voltage threshold;

[0051] The drive adjustment module 9, connected to the switch drive module 2, the self-locking module 6, and the first-level detection module 7, is configured to receive and store pulse signals, reduce the voltage of the pulse signals when receiving the third control signal, and accelerate the rate of reducing the voltage of the pulse signals when receiving the fourth control signal.

[0052] In a specific embodiment, the above-mentioned power switch module 1 may adopt a power switch circuit composed of an IGBT, an inductor, a load, and an input port. The electric energy provided by the input port to the input load can be adjusted by adjusting the conduction degree of the IGBT. The above-mentioned switch drive module 2 may adopt a switch drive circuit composed of a voltage source, a triode, a switch drive device, a logic device, etc. A pulse signal is provided by the switch drive device to improve the driving ability of the pulse signal and output a drive signal. The above-mentioned inductor detection module 3 may adopt an inductor detection circuit composed of a diode and a resistor, and can detect the change rate of the inductor current of the detected power switch module 1 and perform voltage division and clamping processing on the detected signal. The above-mentioned short-circuit protection module 4 may adopt a short-circuit protection circuit composed of a comparator, a threshold device, a trigger, etc. A short-circuit threshold is set by the threshold device, and this short-circuit threshold is used to determine whether the power switch module 1 has a short circuit. When the input signal is greater than the short-circuit threshold, it indicates that the power switch module 1 has a short circuit, and then a first control signal in a high-level state is self-locked and output. The above-mentioned desaturation detection module 5 may adopt a desaturation detection circuit composed of a resistor, a MOS transistor, a diode, an inverter, etc. An overvoltage threshold is set, and this overvoltage threshold is greater than the short-circuit threshold. Voltage sampling is performed on the electric energy input and output by the power switch module 1, overvoltage judgment is performed, and electric energy discharge processing is performed on the power switch module 1. The above-mentioned self-locking module 6 may adopt a self-locking circuit composed of a logic device, a resistor, a diode, etc., and perform self-locking processing on the second control signal in a high-level state output by the desaturation detection module 5. The above-mentioned primary detection module 7 may adopt a primary detection circuit composed of a thyristor, a threshold device, a comparator, etc., and provide a first voltage threshold, and this first voltage threshold is less than the short-circuit threshold. When the input signal is less than the first voltage threshold or the first control signal is received, the drive adjustment module 9 and the secondary detection module 8 are controlled to operate. The above-mentioned secondary detection module 8 may adopt a secondary detection circuit composed of a thyristor, a trigger, a comparator, a threshold device, etc., and can set a second voltage threshold and when the input signal is less than the second voltage threshold, self-lock and output a first protection signal in a low-level state. The above-mentioned drive adjustment module 9 may adopt a drive adjustment circuit composed of a diode, a capacitor, a MOS transistor, a triode, etc., and can adjust the voltage value of the pulse signal output by the switch drive module 2 and adjust the step-down rate.

[0053] In another embodiment, please refer to Figure 1 、 Figure 2 and Figure 3 , the power switch module 1 includes an input port, a first load RL, a first power switch G1, and a first inductor L1;

[0054] Specifically, the input port is connected to the collector of the first power switch G1 through the first load RL. The gate of the first power switch G1 is connected to the switch drive module 2. The emitter of the first power switch G1 is connected to the first end of the first inductor L1, and the second end of the first inductor L1 is grounded.

[0055] In a specific embodiment, the above-mentioned first power switch G1 can be an IGBT.

[0056] Further, the inductor detection module 3 includes a second diode D2, a fifth resistor R5, a sixth resistor R6, a third diode D3, a seventh resistor R7, and an eighth resistor R8;

[0057] Specifically, the anode of the second diode D2 is connected to the first end of the first inductor L1. The cathode of the second diode D2 is connected to one end of the sixth resistor R6, the cathode of the third diode D3, and the first end of the eighth resistor R8 through the fifth resistor R5. The second end of the eighth resistor R8 is connected to the short-circuit protection module 4 and is connected to the anode of the third diode D3, the other end of the sixth resistor R6, and the second end of the first inductor L1 through the seventh resistor R7.

[0058] In a specific embodiment, the above-mentioned second diode D2, fifth resistor R5, sixth resistor R6, and third diode D3 perform voltage division and clamping processing; the above-mentioned eighth resistor R8 and seventh resistor R7 perform voltage division processing.

[0059] Further, the switch driving module 2 includes a first resistor R1, a first power supply VCC1, a first switching tube V1, a second switching tube V2, a second power supply VCC2, a second resistor R2, a first logic device J1, and a switch driving device;

[0060] Specifically, the emitter of the first switching tube V1 is connected to the emitter of the second switching tube V2 and is connected to the gate of the first power switch G1 through the first resistor R1. The collector of the first switching tube V1 is connected to the first power supply VCC1. The base of the first switching tube V1 is connected to the base of the second switching tube V2 and is connected to the Y terminal of the first logic device J1 and the drive adjustment module 9 through the second resistor R2. The B terminal of the first logic device J1 is connected to the switch driving device. The A terminal of the first logic device J1 is connected to the desaturation detection module 5 and the secondary detection module 8. The collector of the second switching tube V2 is connected to the second power supply VCC2.

[0061] In a specific embodiment, the above-mentioned first switching tube V1 can be an NPN-type triode, the second switching tube V2 can be a PNP-type triode, the absolute value of the voltage of the second power supply VCC2 is equal to the voltage of the first power supply VCC1, and the second resistor R2 and the first resistor R1 are used to improve the driving ability of the pulse signal; the above-mentioned first logic device J1 can be an AND gate chip; the above-mentioned switch driving device can be a single-chip microcomputer, which provides the pulse signal required to drive the IGBT.

[0062] Further, the drive adjustment module 9 includes a first diode D1, a first capacitor C1, a third resistor R3, a fourth resistor R4, a first MOS tube Q1, an eighth diode D8, and a third switching tube V3;

[0063] Specifically, the anode of the first diode D1 is connected to the Y terminal of the first logic device J1. The cathode of the first diode D1 is connected to one end of the third resistor R3 and one end of the fourth resistor R4, and is connected to the second power supply VCC2 and the emitter of the third switching transistor V3 through the first capacitor C1. The other end of the third resistor R3 is connected to the drain of the first MOS transistor Q1. The source of the first MOS transistor Q1 is connected to the anode of the eighth diode D8. The gate of the first MOS transistor Q1 is connected to the other end of the fourth resistor R4 and the primary detection module 7. The collector of the third switching transistor V3 is connected to the cathode of the eighth diode D8. The base of the third switching transistor V3 is connected to the self-locking module 6.

[0064] In a specific embodiment, the above-mentioned first diode D1 performs unidirectional power transmission control; the above-mentioned first capacitor C1 is a storage capacitor. The third resistor R3 and the first MOS transistor Q1 can adjust the discharge rate of the first capacitor C1, and then adjust the voltage of the pulse signal at the anode of the first diode D1; the above-mentioned first MOS transistor Q1 can be an N-channel field effect transistor; the above-mentioned third switching transistor V3 can be an NPN-type triode.

[0065] Further, the desaturation detection module 5 includes a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourth diode D4, a third capacitor C3, a second MOS transistor Q2, and a first inverter INV1;

[0066] Specifically, one end of the tenth resistor R10 is connected to the collector of the first power switch G1. The other end of the tenth resistor R10 is connected to the first end of the twelfth resistor R12 and is connected to the second end of the first inductor L1 through the eleventh resistor R11. The second end of the twelfth resistor R12 is connected to the primary detection module 7, the secondary detection module 8, the drain of the second MOS transistor Q2, and one end of the third capacitor C3, and is connected to the cathode of the fourth diode D4 through the thirteenth resistor R13. The anode of the fourth diode D4 is connected to the self-locking module. The source of the second MOS transistor Q2 is connected to the other end of the third capacitor C3 and the ground terminal. The gate of the second MOS transistor Q2 is connected to the output terminal of the first inverter INV1. The input terminal of the first inverter INV1 is connected to the A terminal of the first logic device J1.

[0067] In a specific embodiment, the above-mentioned tenth resistor R10 and eleventh resistor R11 perform voltage division processing; the above-mentioned thirteenth resistor R13 and fourth diode D4 set the overvoltage threshold; the above-mentioned second MOS transistor Q2 can be an N-channel field effect transistor; the above-mentioned first inverter INV1 can be a NOT gate chip.

[0068] In another embodiment, please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4, Figure 5 , Figure 6 and Figure 7 , the self-locking module 6 includes a fourteenth resistor R14, a third power supply VCC3, a fifth diode D5, a sixth diode D6, and a second logic device J2;

[0069] Specifically, the A terminal of the second logic device J2 is connected to the third power supply VCC3 through the fourteenth resistor R14. The B terminal of the second logic device J2 is connected to the cathodes of the sixth diode D6 and the fifth diode D5. The anode of the fifth diode D5 is connected to the anode of the fourth diode D4. The anode of the sixth diode D6 is connected to the Y terminal of the second logic device J2, the base of the third switching transistor V3, and the primary detection module 7.

[0070] In a specific embodiment, the above-mentioned second logic device J2 can be selected as an AND gate chip, which, in cooperation with the fourteenth resistor R14, the third power supply VCC3, the fifth diode D5, and the sixth diode D6, performs high-level self-locking processing on the signal in the high-level state input to the B terminal of the second logic device J2.

[0071] Furthermore, the primary detection module 7 includes a first thyristor S1, a fifteenth resistor R15, a first threshold device, and a second comparator A2;

[0072] Specifically, the anode of the first thyristor S1 is connected to the second terminal of the twelfth resistor R12. The cathode of the first thyristor S1 is connected to the inverting terminal of the second comparator A2 and grounded through the fifteenth resistor R15. The non-inverting terminal of the second comparator A2 is connected to the first threshold device. The control terminal of the first thyristor S1 is connected to the Y terminal of the second logic device J2 and the short-circuit protection module 4. The output terminal of the second comparator A2 is connected to the gate of the first MOS transistor Q1 and the secondary detection module 8.

[0073] In a specific embodiment, the above-mentioned first thyristor S1 can be selected as a unidirectional thyristor; the above-mentioned first threshold device can be composed of a reference power supply and a resistor to provide a first voltage threshold; the above-mentioned second comparator A2 can be selected as an LM358 comparator.

[0074] Furthermore, the secondary detection module 8 includes a second thyristor S2, a sixteenth resistor R16, a second threshold device, a third comparator A3, a second flip-flop U2, and a second inverter INV2;

[0075] Specifically, the anode of the second thyristor S2 is connected to the second end of the twelfth resistor R12. The cathode of the second thyristor S2 is connected to the inverting input terminal of the third comparator A3 and is connected to the D terminal of the second flip-flop U2 and the ground terminal through the sixteenth resistor R16. The output terminal of the third comparator A3 is connected to the CLK terminal of the second flip-flop U2. The control terminal of the second thyristor S2 is connected to the output terminal of the second comparator A2. The non-inverting input terminal of the third comparator A3 is connected to the second threshold device. The Q terminal of the second flip-flop U2 is connected to the input terminal of the second inverter INV2. The output terminal of the second inverter INV2 is connected to the A terminal of the first logic device J1.

[0076] In a specific embodiment, the above-mentioned second thyristor S2 can be a unidirectional thyristor; the above-mentioned third comparator A3 can be an LM358 comparator; the above-mentioned second threshold device can be composed of a reference power supply and a resistor to provide a second voltage threshold; the above-mentioned second flip-flop U2 can be a D flip-flop; the above-mentioned second inverter INV2 can be a NOT gate chip.

[0077] Furthermore, the short-circuit protection module 4 includes a ninth resistor R9, a second capacitor C2, a first comparator A1, a third threshold device, a first flip-flop U1, and a seventh diode D7;

[0078] Specifically, the non-inverting input terminal of the first comparator A1 is connected to one end of the ninth resistor R9 and is connected to the D terminal of the first flip-flop U1 and the ground terminal through the second capacitor C2. The other end of the ninth resistor R9 is connected to the second end of the eighth resistor R8. The inverting input terminal of the first comparator A1 is connected to the third threshold device. The Q terminal of the first flip-flop U1 is connected to the anode of the seventh diode D7. The cathode of the seventh diode D7 is connected to the control terminal of the first thyristor S1.

[0079] In a specific embodiment, the above-mentioned first comparator A1 can be an LM358 comparator; the above-mentioned third threshold device can be composed of a reference power supply and a resistor to provide a short-circuit threshold; the above-mentioned first flip-flop U1 can be a D flip-flop.

[0080] In the short - circuit protection circuit based on the rate of change of inductor current in this embodiment, working electrical energy is accessed through the input port. The switch driving device provides a pulse signal. The first inverter INV1 makes the A terminal of the first logic gate J1 at a high level. Subsequently, the Y terminal of the first logic gate J1 outputs a pulse signal. After being amplified by the second resistor R2, the second power supply VCC2, the first power supply VCC1, the first switching transistor V1, the second switching transistor V2, and the first resistor R1, the pulse signal drives the first power switch G1 to conduct, and then adjusts the working electrical energy input to the first load RL. At this time, the second diode D2, the fifth resistor R5, the sixth resistor R6, the third diode D3, the eighth resistor R8, and the seventh resistor R7 detect, divide the voltage, and clamp the rate of change of the current on the first inductor L1, and output a first detection signal. When the first detection signal is greater than the short - circuit threshold set by the third threshold device, the first comparator A1 outputs a high level, the Q terminal of the first flip - flop U1 changes from a low level to a high level, triggering the first thyristor S1 to conduct, and at the same time making the Y terminal of the second logic gate J2 become a high level, triggering the third switching transistor V3 to conduct. The third switching transistor V3, in cooperation with the eighth diode D8, the first MOS transistor Q1, the third resistor R3, the first diode D1, and the first capacitor C1, reduces the voltage of the pulse signal output by the Y terminal of the first logic gate J1. Then, when turning off the first power switch G1, it reduces the rate of change of the current of the first power switch G1, suppresses the turn - off overvoltage. At the same time, the voltage of the first sampling signal sampled by the tenth resistor R10, the twelfth resistor R12, and the eleventh resistor R11 will decrease. When the first sampling signal is less than the first voltage threshold set by the first threshold device, the second comparator A2 outputs a high level, increasing the gate voltage of the first MOS transistor Q1, increasing the conduction degree of the first MOS transistor Q1, then increasing the voltage - reducing rate of the pulse signal, reducing the conduction degree of the first power switch G1. When the first sampling signal is less than the second voltage threshold set by the second threshold device, the third comparator A3 outputs a high level, the Q terminal of the second flip - flop U2 changes from a low level to a high level, the second inverter INV2 outputs a low level, making the Y terminal of the first logic gate J1 output a low level, stopping the output of the pulse signal, then the first power switch G1 stops working. At the same time, the first inverter INV1 will output a high level and control the second MOS transistor Q2 to conduct, cooperating with the tenth resistor R10 and the twelfth resistor R12 to perform a discharging process on the first power switch G1. Similarly, if the first sampling signal is greater than the over - voltage threshold set by the thirteenth resistor R13 and the fourth diode D4, the second logic gate J2, in cooperation with the fourteenth resistor R14, the third power supply VCC3, the fifth diode D5, and the sixth diode D6, performs self - locking and outputs a third control signal, triggering the third switching transistor V3 and the first thyristor S1 to conduct, then reducing the rate of change of the current of the first power switch G1, suppressing the turn - off overvoltage until the first power switch G1 is turned off.

[0081] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, in any aspect, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0082] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A short-circuit protection circuit based on the rate of change of inductor current, characterized in that: The short-circuit protection circuit based on the inductor current change rate comprises: a power switch module, a switch drive module, an inductor detection module, a short-circuit protection module, a desaturation detection module, a self-locking module, a primary detection module, a secondary detection module and a drive adjustment module; The power switch module is connected to the switch driving module and is used to receive the working power and adjust the voltage of the working power input to the load when receiving the driving signal output by the switch driving module; The switch driving module is connected to the secondary detection module, and is used to provide a pulse signal, amplify the pulse signal, output a driving signal, and stop providing the pulse signal when receiving the first protection signal output by the secondary detection module; The inductance detection module is connected to the power switch module, and is used to detect the current change rate of the inductance of the power switch module and clamp and divide the detected signal to output a first detection signal; The short-circuit protection module is connected to the inductance detection module and is used to filter the first detection signal and self-lock and output the first control signal when the filtered signal is greater than a set short-circuit threshold; The desaturation detection module is connected to the power switch module, the secondary detection module and the switch driving module, and is used to perform voltage sampling on the power switch module and output a first sampling signal, output a second control signal when the first sampling signal is greater than a set overvoltage threshold, and perform power discharge processing on the power switch module when receiving the first protection signal output by the secondary detection module; The self-locking module is connected to the desaturation detection module and is used to perform a high-level self-locking operation and output a third control signal when receiving the second control signal; The primary detection module is connected to the self-locking module and the short-circuit protection module, and is used to receive the first sampling signal when receiving the third control signal or the first control signal, and output a fourth control signal when the first sampling signal is less than a set first voltage threshold; The secondary detection module is connected to the primary detection module, and is used to receive the first sampling signal when receiving the fourth control signal, and when the first sampling signal is less than a set second voltage threshold, output a first protection signal and perform self-locking processing on the first protection signal; The drive adjustment module is connected to the switch drive module, the self-locking module and the primary detection module, and is used to receive and store the pulse signal, reduce the voltage of the pulse signal when receiving the third control signal, and speed up the rate of reducing the voltage of the pulse signal when receiving the fourth control signal; The inductance detection module detects the inductance current change rate of the power switch module and cooperates with the short-circuit protection module to make a short-circuit judgment, triggering the self-locking module and the first-level detection module to work when a short circuit occurs.

2. A short-circuit protection circuit based on inductor current change rate according to claim 1, characterized in that: The power switch module includes an input port, a first load, a first power switch and a first inductor; The input port is connected to the collector of the first power switch through the first load, the gate of the first power switch is connected to the switch driving module, the emitter of the first power switch is connected to the first end of the first inductor, and the second end of the first inductor is grounded.

3. A short-circuit protection circuit based on inductor current change rate according to claim 2, characterized in that: The inductance detection module includes a second diode, a fifth resistor, a sixth resistor, a third diode, a seventh resistor and an eighth resistor; The anode of the second diode is connected to the first end of the first inductor, the cathode of the second diode is connected to one end of the sixth resistor, the cathode of the third diode and the first end of the eighth resistor through the fifth resistor, the second end of the eighth resistor is connected to the short-circuit protection module and connected to the anode of the third diode, the other end of the sixth resistor and the second end of the first inductor through the seventh resistor.

4. A short-circuit protection circuit based on inductor current change rate according to claim 3, characterized in that: The switch driving module includes a first resistor, a first power supply, a first switch tube, a second switch tube, a second power supply, a second resistor, a first logic device and a switch driving device; The emitter of the first switch tube is connected to the emitter of the second switch tube and is connected to the gate of the first power switch through the first resistor, the collector of the first switch tube is connected to the first power supply, the base of the first switch tube is connected to the base of the second switch tube and is connected to the Y end of the first logic device and the drive adjustment module through the second resistor, the B end of the first logic device is connected to the switch drive device, the A end of the first logic device is connected to the desaturation detection module and the secondary detection module, and the collector of the second switch tube is connected to the second power supply.

5. A short-circuit protection circuit based on inductor current change rate according to claim 4, characterized in that: The driving adjustment module includes a first diode, a first capacitor, a third resistor, a fourth resistor, a first MOS tube, an eighth diode and a third switch tube; The anode of the first diode is connected to the Y end of the first logic device, the cathode of the first diode is connected to one end of the third resistor and one end of the fourth resistor and is connected to the second power supply and the emitter of the third switch tube through the first capacitor, the other end of the third resistor is connected to the drain of the first MOS tube, the source of the first MOS tube is connected to the anode of the eighth diode, the gate of the first MOS tube is connected to the other end of the fourth resistor and the primary detection module, the collector of the third switch tube is connected to the cathode of the eighth diode, and the base of the third switch tube is connected to the self-locking module.

6. A short-circuit protection circuit based on inductor current change rate according to claim 5, characterized in that: The desaturation detection module includes a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourth diode, a third capacitor, a second MOS tube and a first inverter; One end of the tenth resistor is connected to the collector of the first power switch, the other end of the tenth resistor is connected to the first end of the twelfth resistor and is connected to the second end of the first inductor through the eleventh resistor, the second end of the twelfth resistor is connected to the primary detection module, the secondary detection module, the drain of the second MOS tube and one end of the third capacitor and is connected to the cathode of the fourth diode through the thirteenth resistor, the anode of the fourth diode is connected to the self-locking module, the source of the second MOS tube is connected to the other end of the third capacitor and the ground, the gate of the second MOS tube is connected to the output end of the first inverter, and the input end of the first inverter is connected to the A end of the first logic device.

7. A short-circuit protection circuit based on inductor current change rate according to claim 6, characterized in that: The self-locking module includes a fourteenth resistor, a third power supply, a fifth diode, a sixth diode and a second logic device; The A end of the second logic device is connected to the third power supply through the fourteenth resistor, the B end of the second logic device is connected to the cathode of the sixth diode and the cathode of the fifth diode, the anode of the fifth diode is connected to the anode of the fourth diode, and the anode of the sixth diode is connected to the Y end of the second logic device, the base of the third switch tube and the first-level detection module.

8. The short-circuit protection circuit based on the inductor current change rate according to claim 7, characterized in that: The primary detection module includes a first thyristor, a fifteenth resistor, a first threshold device, and a second comparator; The anode of the first thyristor is connected to the second end of the twelfth resistor, the cathode of the first thyristor is connected to the inverting end of the second comparator and grounded through the fifteenth resistor, the non-inverting end of the second comparator is connected to the first threshold device, the control end of the first thyristor is connected to the Y end of the second logic device and the short-circuit protection module, and the output end of the second comparator is connected to the gate of the first MOS tube and the secondary detection module.

9. The short-circuit protection circuit based on the inductor current change rate according to claim 7, characterized in that: The secondary detection module includes a second thyristor, a sixteenth resistor, a second threshold device, a third comparator, a second trigger and a second inverter; The anode of the second thyristor is connected to the second end of the twelfth resistor, the cathode of the second thyristor is connected to the inverting end of the third comparator and is connected to the D end and the ground end of the second trigger through the sixteenth resistor, the output end of the third comparator is connected to the CLK end of the second trigger, the control end of the second thyristor is connected to the output end of the second comparator, the in-phase end of the third comparator is connected to the second threshold device, the Q end of the second trigger is connected to the input end of the second inverter, and the output end of the second inverter is connected to the A end of the first logic device.

10. The short-circuit protection circuit based on the inductor current change rate according to claim 8, characterized in that: The short circuit protection module includes a ninth resistor, a second capacitor, a first comparator, a third threshold device, a first trigger and a seventh diode; The in-phase end of the first comparator is connected to one end of the ninth resistor and is connected to the D end and the ground end of the first trigger through the second capacitor. The other end of the ninth resistor is connected to the second end of the eighth resistor. The inverting end of the first comparator is connected to the third threshold device. The Q end of the first trigger is connected to the anode of the seventh diode, and the cathode of the seventh diode is connected to the control end of the first thyristor.

Images