High-side MOS tube driving protection circuit with current detection function

Abstract

The utility model relates to the technical field of circuit protection, in particular to a high-side MOS (Metal Oxide Semiconductor) tube driving protection circuit with a current detection function. Comprising a working circuit, a protection circuit and a current detection module. The working circuit comprises an MOS tube Q2, a third resistor R2 and a fourth resistor R4, a source electrode of the MOS tube Q2 is connected with power input, a drain electrode of the MOS tube Q2 is connected with output, one end of the second resistor R2 is connected with control input, the other end of the second resistor R2 is connected with the fourth resistor R4, and the other end of the fourth resistor R4 is connected with a grid electrode of the MOS tube Q2. The protection circuit comprises a third diode D3, a capacitor C1, a first triode Q1B, a first voltage stabilizing diode D1, a second resistor R2 and a first resistor R1. And the current detection module comprises a fifth resistor R5 and a current detection module.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit protection, in particular to a high-side MOS tube driving protection circuit with a current detection function. Background Art

[0002] MOS tube is a metal-oxide-semiconductor field effect transistor, or metal-insulator-semiconductor. Field effect transistor is a semiconductor device that controls the current of the output loop by controlling the electric field of the input loop to the right. It conducts electricity only by the majority carriers in the semiconductor, and is also called a unipolar transistor. Field effect transistor is a voltage-controlled semiconductor device with the advantages of high input resistance, low noise, low power consumption, large dynamic range, easy integration, no secondary breakdown phenomenon, and wide safe working area.

[0003] In the circuit using MOS tube as switch, when MOS tube is turned on, the source and drain are connected, and the internal resistance is very small. If the load at the output end is disconnected and the drain is disconnected to the ground, the current between the source and the drain will instantly rise to a larger value, causing the MOS tube Q1 to burn out. Although there are intelligent MOS with protection that can avoid burning through short-circuit protection, the cost is too high. Utility Model Content

[0004] The technical problem solved by the utility model is to provide a high-side MOS tube driving protection circuit with a current detection function, which can prevent the MOS tube from burning out after a load short circuit at the output end of the MOS tube and detect the load end current at the same time.

[0005] The basic scheme provided by the utility model: a high-side MOS tube driving protection circuit with a current detection function, including a working circuit, a protection circuit and a current detection module; the working circuit includes a MOS tube Q2, a third resistor R3, a fourth resistor R4, a first voltage regulator diode D1, and a second band-blocking transistor Q1A, the source of the MOS tube Q2 is connected to a power input, the drain of the MOS tube Q2 is connected to an output, one end of the third resistor R3 is connected to the collector of the second band-blocking transistor Q1A, the other end of the third resistor R3 is connected to the fourth resistor R4, the other end of the fourth resistor R4 is connected to the gate of the MOS tube Q2, the base of the second band-blocking transistor Q1A is connected to a control input, the emitter of the second band-blocking transistor Q1A is connected to ground, the cathode of the first voltage regulator diode D1 is connected to a power supply, and the anode of the first voltage regulator diode D1 is connected to the gate of the MOS tube Q2;

[0006] The protection circuit includes a third diode D3, a capacitor C1, a first transistor Q1B, a second resistor R2, a first resistor R1, and a transient suppression diode TVS1, wherein the anode of the third diode D3 is connected to the drain of the MOS transistor Q2, the cathode of the third diode D3 is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to the emitter of the first band-stop transistor Q1B, the emitter of the first band-stop transistor Q1B is also connected to the power input, the collector of the first band-stop transistor Q1B is connected to the common end of the fourth resistor R4 and the gate of the MOS transistor Q2, the base of the first band-stop transistor Q1B is connected to the third resistor R3 through the first resistor R1 and the second resistor R2, and the common end of the second resistor R2 and the first resistor R1 is connected to the common end of the capacitor C1 and the cathode of the third diode D3;

[0007] The current detection module includes a fifth resistor R5 and a current detection chip. One end of the fifth resistor R5 is electrically connected to the drain of the MOS tube Q2, and the other end of the fifth resistor R5 is electrically connected to the current detection module.

[0008] The principle and advantage of the utility model are: when the output end of the circuit (i.e., the drain of the MOS tube Q2) is short-circuited to the ground, the common terminal voltage of the drain of the MOS tube Q2 and the positive electrode of the third diode D3 changes from high to low, and the positive-negative voltage difference of the third diode D3 does not reach its conduction condition, resulting in the first capacitor C1 being unable to maintain charge balance. At this time, the first capacitor C1 is discharged through the second resistor R2, the third resistor R3, and the second transistor Q1A. After the first capacitor C1 is discharged, the common terminal voltage of the first capacitor C1 and the fourth resistor R4 is reduced, and then the first band-resistance transistor Q1B reaches the conduction condition and conducts. After Q1B is turned on, the gate-source voltage difference of the MOS tube does not reach the conduction condition of the MOS tube, so that the MOS tube Q2 is turned off, and Q2 is prevented from being burned due to a short circuit. After Q2 is turned off, the circuit is in a self-locking state. Only by eliminating the short-circuit fault of the output end and re-controlling the input signal can the normal working state of the circuit be restored.

[0009] Other control modules in the circuit can detect the current flowing through R5 in real time through the current signal output port of the current detection module. When the drive is normally turned on, the normal operation, open circuit, and overcurrent conditions of the output load end can be judged by the current flowing through R5.

[0010] It also includes a short circuit detection module, which includes a sixth resistor R6 and a fourth voltage stabilizing diode D4;

[0011] The positive electrode of the fourth voltage zener diode is connected to the emitter of the second band-blocking transistor Q1A, the other end of the fourth voltage zener diode is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is electrically connected to the cathode of the third diode D3 and the common end of the drain of the MOS tube Q2, and the common end of the sixth resistor R6 and the fourth voltage zener diode D4 is connected to the short-circuit detection port.

[0012] Through the "short circuit detection" port, when the drive is normally turned on, the port is high level, when the output is short-circuited, the port is low level, and other control modules in the circuit can collect the signal to realize the short circuit detection function.

[0013] The second capacitor C2 and the second diode D2 are used to absorb reverse surge voltage and burrs at the load end. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The utility model is a schematic diagram of an embodiment of a high-side MOS tube driving protection circuit with a current detection function. DETAILED DESCRIPTION

[0015] The following is further described in detail through specific implementation methods:

[0016] The embodiment is basically as shown in the attached Figure 1 As shown:

[0017] It includes a working circuit, a protection circuit and a current detection module; the working circuit includes a MOS tube Q2, a third resistor R3, a fourth resistor R4, a first voltage regulator diode D1, and a second band-blocking transistor Q1A; the source of the MOS tube Q2 is connected to a power input, the drain of the MOS tube Q2 is connected to an output, one end of the third resistor R3 is connected to a collector of the second band-blocking transistor Q1A, the other end of the third resistor R3 is connected to a fourth resistor R4, the other end of the fourth resistor R4 is connected to a gate of the MOS tube Q2, the base of the second band-blocking transistor Q1A is connected to a control input, the emitter of the second band-blocking transistor Q1A is connected to a ground, the cathode of the first voltage regulator diode D1 is connected to a power supply, and the anode of the first voltage regulator diode D1 is connected to the gate of the MOS tube Q2;

[0018] The protection circuit includes a third diode D3, a capacitor C1, a first transistor Q1B, a second resistor R2, a first resistor R1, and a transient suppression diode TVS1, wherein the anode of the third diode D3 is connected to the drain of the MOS transistor Q2, the cathode of the third diode D3 is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to the emitter of the first band-stop transistor Q1B, the emitter of the first band-stop transistor Q1B is also connected to the power input, the collector of the first band-stop transistor Q1B is connected to the common end of the fourth resistor R4 and the gate of the MOS transistor Q2, the base of the first band-stop transistor Q1B is connected to the third resistor R3 through the first resistor R1 and the second resistor R2, and the common end of the second resistor R2 and the first resistor R1 is connected to the common end of the capacitor C1 and the cathode of the third diode D3;

[0019] The current detection module includes a fifth resistor R5 and a current detection module, one end of the fifth resistor R5 is electrically connected to the drain of the MOS tube Q2, and the other end of the fifth resistor R5 is electrically connected to the current detection module. The current detection chip is specifically TP181, the IN+ pin is connected to the common end of the MOS tube Q2 and the fifth resistor R5, and the IN- pin is connected to the other end of the sixth resistor R6. The Out pin is connected to the current signal output, the V+ pin is connected to the 3.3V power supply, and the GND pin and the REF pin are grounded.

[0020] It also includes a short circuit detection module, which includes a sixth resistor R6 and a fourth voltage stabilizing diode D4;

[0021] The positive electrode of the fourth voltage zener diode is connected to the emitter of the second band-blocking transistor Q1A, the other end of the fourth voltage zener diode is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is electrically connected to the cathode of the third diode D3 and the common end of the drain of the MOS tube Q2, and the common end of the sixth resistor R6 and the fourth voltage zener diode D4 is connected to the short-circuit detection port.

[0022] When the output end of the circuit (i.e., the drain of the MOS tube Q2) is short-circuited to the ground, the common terminal voltage of the drain of the MOS tube Q2 and the positive electrode of the third diode D3 changes from high to low, and the positive-negative voltage difference of the third diode D3 does not meet its conduction condition, resulting in the first capacitor C1 being unable to maintain charge balance. At this time, the first capacitor C1 is discharged through the second resistor R2, the third resistor R3, and the second transistor Q1A. After the first capacitor C1 is discharged, the common terminal voltage of the first capacitor C1 and the fourth resistor R4 is reduced, and then the first band-resistance transistor Q1B meets the conduction condition and conducts. After Q1B is turned on, the gate-source voltage difference of the MOS tube does not meet the conduction condition of the MOS tube, so that the MOS tube Q2 is turned off to prevent Q2 from being burned due to a short circuit. After Q2 is turned off, the circuit is in a self-locking state. Only by eliminating the short-circuit fault at the output end and re-controlling the input signal can the normal working state of the circuit be restored.

[0023] Other control modules in the circuit can detect the current flowing through R5 in real time through the current signal output port of the current detection module. When the drive is normally turned on, the normal operation, open circuit, and overcurrent conditions of the output load end can be judged by the current flowing through R5.

[0024] Through the "short circuit detection" port, when the drive is normally turned on, the port is high level, when the output is short-circuited, the port is low level, and other control modules in the circuit can collect the signal to realize the short circuit detection function.

[0025] The second capacitor C2 and the second diode D2 are used to absorb reverse surge voltage and burrs at the load end.

[0026] The above are only embodiments of the utility model. The common sense such as the known specific structures and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the utility model before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for the technicians in this field, without departing from the structure of the utility model, several deformations and improvements can be made, which should also be regarded as the protection scope of the utility model, which will not affect the effect of the implementation of the utility model and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to explain the content of the claims.

Claims

1. A high-side MOS tube drive protection circuit with current detection function, characterized in that: It includes a working circuit, a protection circuit and a current detection module; the working circuit includes a MOS tube Q2, a third resistor R3, a fourth resistor R4, a first voltage regulator diode D1, and a second band-blocking transistor Q1A; the source of the MOS tube Q2 is connected to a power input, the drain of the MOS tube Q2 is connected to an output, one end of the third resistor R3 is connected to a collector of the second band-blocking transistor Q1A, the other end of the third resistor R3 is connected to a fourth resistor R4, the other end of the fourth resistor R4 is connected to a gate of the MOS tube Q2, the base of the second band-blocking transistor Q1A is connected to a control input, the emitter of the second band-blocking transistor Q1A is connected to a ground, the cathode of the first voltage regulator diode D1 is connected to a power supply, and the anode of the first voltage regulator diode D1 is connected to the gate of the MOS tube Q2; The protection circuit includes a third diode D3, a capacitor C1, a first transistor Q1B, a second resistor R2, a first resistor R1, and a transient suppression diode TVS1, wherein the anode of the third diode D3 is connected to the drain of the MOS transistor Q2, the cathode of the third diode D3 is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to the emitter of the first band-stop transistor Q1B, the emitter of the first band-stop transistor Q1B is also connected to the power input, the collector of the first band-stop transistor Q1B is connected to the common end of the fourth resistor R4 and the gate of the MOS transistor Q2, the base of the first band-stop transistor Q1B is connected to the third resistor R3 through the first resistor R1 and the second resistor R2, and the common end of the second resistor R2 and the first resistor R1 is connected to the common end of the capacitor C1 and the cathode of the third diode D3; The current detection module includes a fifth resistor R5 and a current detection chip. One end of the fifth resistor R5 is electrically connected to the drain of the MOS tube Q2, and the other end of the fifth resistor R5 is electrically connected to the current detection module.

2. The high-side MOS tube driving protection circuit with current detection function according to claim 1, characterized in that: It also includes a short circuit detection module, which includes a sixth resistor R6 and a fourth voltage stabilizing diode D4; The positive electrode of the fourth voltage zener diode is connected to the emitter of the second band-blocking transistor Q1A, the other end of the fourth voltage zener diode is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is electrically connected to the cathode of the third diode D3 and the common end of the drain of the MOS tube Q2, and the common end of the sixth resistor R6 and the fourth voltage zener diode D4 is connected to the short-circuit detection port.

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