H-bridge drive circuit with overcurrent detection

Abstract

The utility model provides an H-bridge drive circuit with overcurrent detection. The H-bridge drive circuit comprises a first drive circuit, a second drive circuit, a first switch circuit connected with the first drive circuit, and a second switch circuit connected with the second drive circuit. The first switching circuit comprises a first switching device and a second switching device; a third port of the second switching device is connected in series with the first sampling resistor and grounded; the second switching circuit comprises a third switching device and a fourth switching device; and a third port of the fourth switching device is connected in series with a second sampling resistor and grounded. According to the utility model, through the first sampling resistor and the second sampling resistor, current detection is carried out on the switching device in the H-bridge driving circuit, the response speed is fast, and through combination with the overcurrent protection circuit, when overcurrent is detected, for example, the switching device is not effectively switched on or switched off, the circuit is triggered to be switched off, so that the purpose of protecting the circuit is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of H-bridge drive circuits, in particular to an H-bridge drive circuit with overcurrent detection. Background Art

[0002] The drive circuit for driving MOSFET in the prior art lacks an overcurrent detection function. At the same time, a digital control unit is usually used for drive control, which is costly and has a complex circuit design. The H-bridge drive circuit is a common DC motor control circuit, which mainly realizes the forward and reverse drive of the DC motor. If the switching device in the H-bridge drive circuit cannot be effectively turned on or off, it may cause the current to pass through other unexpected paths, thereby causing overcurrent, which may cause the motor to burn or be damaged. Therefore, there is an urgent need for an H-bridge drive circuit with low cost, simple circuit, and overcurrent detection capability. Utility Model Content

[0003] In view of the deficiencies in the prior art, the utility model provides an H-bridge drive circuit with overcurrent detection, which solves the problem in the prior art that the switching device of the H-bridge drive circuit causes overcurrent when it is not effectively turned on or off, resulting in burning or damage to the motor.

[0004] According to an embodiment of the utility model, an H-bridge driving circuit with overcurrent detection includes:

[0005] a first drive circuit, a second drive circuit, a first switch circuit connected to the first drive circuit, and a second switch circuit connected to the second drive circuit;

[0006] The first switch circuit includes a first switch device and a second switch device;

[0007] The first port of the first switch device is connected to a power source, the second port of the first switch device is connected to the first drive circuit, and the third port of the first switch device is connected to the first port of the second switch device;

[0008] The second port of the second switch device is connected to the first drive circuit, and the third port of the second switch device is connected in series with the first sampling resistor and grounded;

[0009] The second switch circuit includes a third switch device and a fourth switch device;

[0010] The first port of the third switch device is connected to a power source, the second port of the third switch device is connected to the second drive circuit, and the third port of the third switch device is connected to the first port of the fourth switch device;

[0011] The second port of the fourth switch device is connected to the second drive circuit, and the third port of the fourth switch device is connected in series with the second sampling resistor and grounded;

[0012] The third port of the first switching device and the first port of the second switching device are connected to one end of the motor, and the third port of the third switching device and the first port of the fourth switching device are connected to the other end of the motor.

[0013] Optionally, a first discharge circuit is connected in series between the second port of the first switch device and the third port of the first switch device.

[0014] Optionally, the first discharge circuit includes a first capacitor, a first resistor and a first diode;

[0015] The first capacitor, the first resistor and the first diode are connected in parallel and then in series between the second port of the first switch device and the third port of the first switch device.

[0016] Optionally, a second discharge circuit is connected in series between the second port of the second switch device and the third port of the second switch device.

[0017] Optionally, the second discharge circuit includes a second capacitor, a second resistor and a second diode;

[0018] The second capacitor, the second resistor and the second diode are connected in parallel and in series between the second port of the second switch device and the third port of the second switch device.

[0019] Optionally, a third discharge circuit is connected in series between the second port of the third switch device and the third port of the third switch device.

[0020] Optionally, the third discharge circuit includes a third capacitor, a third resistor and a third diode;

[0021] The third capacitor, the third resistor and the third diode are connected in parallel and in series between the second port of the third switch device and the third port of the third switch device.

[0022] Optionally, a fourth discharge circuit is connected in series between the second port of the fourth switch device and the third port of the fourth switch device.

[0023] Optionally, the fourth discharge circuit includes a fourth capacitor, a fourth resistor and a fourth diode;

[0024] The fourth capacitor, the fourth resistor and the fourth diode are connected in parallel and then connected in series between the second port of the fourth switch device and the third port of the fourth switch device.

[0025] Optionally, the first switch device is an N-channel MOS transistor, the second switch device is an N-channel MOS transistor, the third switch device is an N-channel MOS transistor, and the fourth switch device is an N-channel MOS transistor.

[0026] The technical principle of the utility model is: the first drive circuit drives the first switch circuit to work, and the second drive circuit drives the second switch circuit to work, and under the influence of one current signal, the first drive circuit turns on the first switch device of the first switch circuit and turns off the second switch device, the second drive circuit turns off the third switch device of the second switch circuit and turns on the fourth switch device, the motor rotates forward, and the second sampling resistor collects the current size; and under the influence of another current signal, the first drive circuit turns off the first switch device of the first switch circuit and turns on the second switch device, the second drive circuit turns on the third switch device of the second switch circuit and turns off the fourth switch device, the motor reverses, and the first sampling resistor collects the current size.

[0027] Compared with the prior art, the utility model has the following beneficial effects: through the first sampling resistor and the second sampling resistor, the current of the switching device in the H-bridge drive circuit is detected, the response speed is fast, and combined with the overcurrent protection circuit, the circuit is triggered to disconnect when the overcurrent is detected, thereby achieving the purpose of protecting the circuit, and the cost is low and the circuit structure is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The figure is a schematic diagram of the structure of an H-bridge driving circuit with overcurrent detection according to an embodiment of the utility model.

[0029] Figure 2 The figure is a circuit structure diagram of an H-bridge driving circuit with overcurrent detection according to another embodiment of the present invention. DETAILED DESCRIPTION

[0030] The technical solution of the present utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0031] like Figure 1 As shown, an embodiment of the utility model proposes an H-bridge drive circuit with overcurrent detection, including a first drive circuit 1, a second drive circuit 2, a first switch circuit 3 connected to the first drive circuit 1, and a second switch circuit 4 connected to the second drive circuit 2; wherein the first switch circuit 3 includes a first switch device 31 and a second switch device 32, which are the upper bridge arm of the H-bridge drive circuit, and the second switch circuit 4 includes a third switch device 41 and a fourth switch device 42, which are the lower bridge arm of the H-bridge drive circuit.

[0032] The connection relationship between the above parts is as follows:

[0033] The first port of the first switch device 31 is connected to the power supply VCC, the second port of the first switch device 31 is connected to the first drive circuit 1, and the third port of the first switch device 31 is connected to the first port of the second switch device 32; the second port of the second switch device 32 is connected to the first drive circuit 1, and the third port of the second switch device 32 is connected in series with the first sampling resistor RS1 and grounded; the first port of the third switch device 41 is connected to the power supply VCC, the second port of the third switch device 41 is connected to the second drive circuit 2, and the third port of the third switch device 41 is connected to the first port of the fourth switch device 42; the second port of the fourth switch device 42 is connected to the second drive circuit 2, and the third port of the fourth switch device 42 is connected in series with the second sampling resistor RS2 and grounded; the third port of the first switch device 31 and the first port of the second switch device 32 are connected to one end of the motor M, and the third port of the third switch device 41 and the first port of the fourth switch device 42 are connected to the other end of the motor M.

[0034] The detailed working process of this embodiment is as follows: the first drive circuit 1 drives the first switch circuit 3 to work, the second drive circuit 2 drives the second switch circuit 4 to work, and under the influence of one current signal, the first drive circuit 1 turns on the first switch device 31 of the first switch circuit 3 and turns off the second switch device 32, the second drive circuit 2 turns off the third switch device 41 of the second switch circuit 4 and turns on the fourth switch device 42, the motor M rotates forward, and the second sampling resistor RS2 collects the current magnitude of the passing current; and under the influence of another current signal, the first drive circuit 1 turns off the first switch device 31 of the first switch circuit 3 and turns on the second switch device 32, the second drive circuit 2 turns on the third switch device 41 of the second switch circuit 4 and turns off the fourth switch device 42, the motor M rotates reversely, and the first sampling resistor RS1 collects the current magnitude of the passing current. Through the first sampling resistor RS1 and the second sampling resistor RS2, the switch device in the H-bridge drive circuit is current-detected, and the response speed is fast. Combined with the overcurrent protection circuit, when overcurrent is detected, if the switch device is not effectively turned on or off, the disconnection circuit is triggered to achieve the purpose of protecting the circuit.

[0035] like Figure 2 As shown, another embodiment of the present invention provides an H-bridge driving circuit with overcurrent detection, which also protects the switching device through a discharge circuit. Figure 2 In the embodiment, a first discharge loop 5 is connected in series between the second port of the first switch device 31 and the third port of the first switch device 31. Exemplarily, the first discharge loop 5 includes a first capacitor C1, a first resistor R1 and a first diode D1; the first capacitor C1, the first resistor R1 and the first diode D1 are connected in parallel and connected in series between the second port of the first switch device 31 and the third port of the first switch device 31.

[0036] The structures of the discharge circuits used by the second switch device 32, the third switch device 41 and the fourth switch device 42 are the same as those of the first switch device 31. Figure 2 , a second discharge loop 6 is connected in series between the second port of the second switch device 32 and the third port of the second switch device 32. The second discharge loop 6 includes a second capacitor C2, a second resistor R2, and a second diode D2; the second capacitor C2, the second resistor R2, and the second diode D2 are connected in parallel and connected in series between the second port of the second switch device 32 and the third port of the second switch device 32. A third discharge loop 7 is connected in series between the second port of the third switch device 41 and the third port of the third switch device 41. The third discharge loop 7 includes a third capacitor C3, a third resistor R3, and a third diode D3; the third capacitor C3, the third resistor R3, and the third diode D3 are connected in parallel and connected in series between the second port of the third switch device 41 and the third port of the third switch device 41. A fourth discharge loop 8 is connected in series between the second port of the fourth switch device 42 and the third port of the fourth switch device 42. The fourth discharge loop 8 includes a fourth capacitor C4 , a fourth resistor R4 and a fourth diode D4 ; the fourth capacitor C4 , the fourth resistor R4 and the fourth diode D4 are connected in parallel and then in series between the second port of the fourth switch device 42 and the third port of the fourth switch device 42 .

[0037] In one embodiment, the first switch device 31 is an N-channel MOS transistor, the second switch device 32 is an N-channel MOS transistor, the third switch device 41 is an N-channel MOS transistor, and the fourth switch device 42 is an N-channel MOS transistor. Then the first end of the first switch device 31 is the drain of the N-channel MOS transistor, the second end of the first switch device 31 is the gate of the N-channel MOS transistor, and the third end of the first switch device 31 is the source of the N-channel MOS transistor. The first end of the second switch device 32 is the drain of the N-channel MOS transistor, the second end of the second switch device 32 is the gate of the N-channel MOS transistor, and the third end of the second switch device 32 is the source of the N-channel MOS transistor. The first end of the third switch device 41 is the drain of the N-channel MOS transistor, the second end of the third switch device 41 is the gate of the N-channel MOS transistor, and the third end of the third switch device 41 is the source of the N-channel MOS transistor. A first end of the fourth switch device 42 is a drain of the N-channel MOS transistor, a second end of the fourth switch device 42 is a gate of the N-channel MOS transistor, and a third end of the fourth switch device 42 is a source of the N-channel MOS transistor.

[0038] Figure 2 Also shown is a structure of the first drive circuit 1 and the second drive circuit 2. Figure 2In the embodiment, the first driving circuit 1 includes a first half-bridge driving chip U1, a fifth diode D5, a fifth resistor R5, a sixth resistor R6, a fifth capacitor C5 and a sixth capacitor C6. The VCC terminal of the first half-bridge driving chip U1 is electrically connected to a power supply with a voltage of 15V; the HIN terminal of the first half-bridge driving chip U1 is connected to a high-level input; the LIN terminal of the first half-bridge driving chip U1 is connected to a low-level input; the COM terminal of the first half-bridge driving chip U1 is electrically connected to a reference voltage terminal GND; a fifth capacitor C5 is also connected in series between the VCC terminal of the first half-bridge driving chip U1 and the COM terminal of the first half-bridge driving chip U1; the VB terminal of the first half-bridge driving chip U1 is a voltage input terminal, and the input terminal of the fifth diode D5 is connected to the power supply with a voltage of 15V. The output end of the fifth diode D5 is electrically connected to the VB end of the first half-bridge driver chip U1; the HO end of the first half-bridge driver chip U1 is connected in series with a fifth resistor R5 and then connected to the input end of the first discharge loop; the VS end of the first half-bridge driver chip U1 is a floating power supply bias end, which is simultaneously connected to one end of the motor M and one end of the sixth capacitor C6, and the other end of the sixth capacitor C6 is connected to the output end of the fifth diode D5; the LO end of the first half-bridge driver chip U1 is connected in series with a sixth resistor R6 and then connected to the input end of the second discharge loop. The second drive circuit 2 includes a second half-bridge driver chip U2, a sixth diode D6, a seventh resistor R7, an eighth resistor R8, a seventh capacitor C7 and an eighth capacitor C8. The VCC terminal of the second half-bridge driver chip U2 is electrically connected to a power supply with a voltage of 15V; the HIN terminal of the second half-bridge driver chip U2 is connected to a high-level input; the LIN terminal of the second half-bridge driver chip U2 is connected to a low-level input; the COM terminal of the second half-bridge driver chip U2 is electrically connected to the reference voltage terminal GND; a seventh capacitor C7 is also connected in series between the VCC terminal of the second half-bridge driver chip U2 and the COM terminal of the second half-bridge driver chip U2; the VB terminal of the second half-bridge driver chip U2 is a voltage input terminal, and the input terminal of the sixth diode D6 is electrically connected to the 15V power supply. The output end of the sixth diode D6 is electrically connected to the VB end of the second half-bridge driver chip U2; the HO end of the second half-bridge driver chip U2 is connected in series with a seventh resistor R7 and then connected to the input end of the third discharge loop 7; the VS end of the second half-bridge driver chip U2 is a floating power supply bias end, which is simultaneously connected to the other end of the motor M and to one end of the eighth capacitor C8, and the other end of the eighth capacitor C8 is connected to the output end of the sixth diode D6; the LO end of the second half-bridge driver chip U2 is connected in series with an eighth resistor R8 and then connected to the input end of the fourth discharge loop 8.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. An H-bridge drive circuit with overcurrent detection, characterized in that: include: a first drive circuit, a second drive circuit, a first switch circuit connected to the first drive circuit, and a second switch circuit connected to the second drive circuit; The first switch circuit includes a first switch device and a second switch device; The first port of the first switch device is connected to a power source, the second port of the first switch device is connected to the first drive circuit, and the third port of the first switch device is connected to the first port of the second switch device; The second port of the second switch device is connected to the first drive circuit, and the third port of the second switch device is connected in series with the first sampling resistor and grounded; The second switch circuit includes a third switch device and a fourth switch device; The first port of the third switch device is connected to a power source, the second port of the third switch device is connected to the second drive circuit, and the third port of the third switch device is connected to the first port of the fourth switch device; The second port of the fourth switch device is connected to the second drive circuit, and the third port of the fourth switch device is connected in series with the second sampling resistor and grounded; The third port of the first switching device and the first port of the second switching device are connected to one end of the motor, and the third port of the third switching device and the first port of the fourth switching device are connected to the other end of the motor.

2. The H-bridge driving circuit with overcurrent detection as claimed in claim 1, characterized in that: A first discharge loop is connected in series between the second port of the first switch device and the third port of the first switch device.

3. The H-bridge driving circuit with overcurrent detection as claimed in claim 2, characterized in that: The first discharge circuit includes a first capacitor, a first resistor and a first diode; The first capacitor, the first resistor and the first diode are connected in parallel and then in series between the second port of the first switch device and the third port of the first switch device.

4. The H-bridge driving circuit with overcurrent detection as claimed in claim 1, characterized in that: A second discharge circuit is connected in series between the second port of the second switch device and the third port of the second switch device.

5. The H-bridge driving circuit with overcurrent detection as claimed in claim 4, characterized in that: The second discharge circuit includes a second capacitor, a second resistor and a second diode; The second capacitor, the second resistor and the second diode are connected in parallel and in series between the second port of the second switch device and the third port of the second switch device.

6. The H-bridge driving circuit with overcurrent detection as claimed in claim 1, characterized in that: A third discharge loop is connected in series between the second port of the third switch device and the third port of the third switch device.

7. The H-bridge driving circuit with overcurrent detection as claimed in claim 6, characterized in that: The third discharge circuit includes a third capacitor, a third resistor and a third diode; The third capacitor, the third resistor and the third diode are connected in parallel and in series between the second port of the third switch device and the third port of the third switch device.

8. The H-bridge driving circuit with overcurrent detection as claimed in claim 1, characterized in that: A fourth discharge loop is connected in series between the second port of the fourth switch device and the third port of the fourth switch device.

9. The H-bridge driving circuit with overcurrent detection as claimed in claim 8, characterized in that: The fourth discharge circuit includes a fourth capacitor, a fourth resistor and a fourth diode; The fourth capacitor, the fourth resistor and the fourth diode are connected in parallel and then connected in series between the second port of the fourth switch device and the third port of the fourth switch device.

10. The H-bridge driving circuit with overcurrent detection according to any one of claims 1 to 9, characterized in that: The first switch device is an N-channel MOS transistor, the second switch device is an N-channel MOS transistor, the third switch device is an N-channel MOS transistor, and the fourth switch device is an N-channel MOS transistor.

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