H-bridge driving circuit with clamping protection

Abstract

The utility model relates to the technical field of circuit protection, in particular to an H-bridge driving circuit with clamping protection, which comprises an H-bridge main circuit, the H-bridge main circuit comprises four metal oxide semiconductor (MOS) tubes M1, M2, M3 and M4, the H-bridge driving circuit further comprises two independent clamping protection circuits which are respectively connected with grid electrodes of the MOS tubes M3 and M4 under the H-bridge main circuit, and each clamping protection circuit comprises a first current source biasing circuit, a second current source biasing circuit, a third current source biasing circuit and a fourth current source biasing circuit, the first current source biasing circuit is used for controlling pull-up capability, the second current source biasing circuit is used for controlling pull-down capability, and output ends of the first current source biasing circuit and the second current source biasing circuit are respectively provided with a tg switching tube. Compared with the prior art, the H-bridge protection circuit has the advantages that through the arrangement of the H-bridge protection circuit, a transistor in an H-bridge circuit can be protected only by constructing a clamping voltage by using a current source, overcharge of a follow current to the circuit is reduced, and the H-bridge protection circuit does not need to depend on a sampling voltage and other voltages.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit protection, in particular to an H-bridge driving circuit with clamping protection. Background Art

[0002] An H-bridge is an electronic circuit that reverses the voltage or changes the direction of the current at the connected load or output terminal. This circuit is widely used in robotics and other practical applications, such as forward and reverse control of DC motors, speed regulation, and stepper motor drives (particularly bipolar stepper motors, which require two H-bridge motor controllers). It is also used in power electronics such as most DC-to-AC power converters (such as inverters and frequency converters) and some DC-to-DC converters (such as push-pull converters). Due to the characteristics of inductance, traditional H-bridge circuits do not abruptly interrupt current changes. This generates a large reverse electromotive force (EMF) when the current continues to flow, flowing from ground to the power supply. This causes the power supply voltage to rise, potentially exceeding the withstand voltage of the transistors on the left and right sides of the H-bridge, posing a risk of breakdown. To address this issue, a new H-bridge driver circuit with clamping protection is needed. Utility Model Content

[0003] The purpose of the utility model is to overcome the deficiencies of the prior art and provide an H-bridge drive circuit with clamping protection to reduce the risk of breakdown of transistors on the upper left and right sides of the H-bridge, thereby protecting the circuit.

[0004] To achieve the above objectives, a clamping protection function control circuit for an H-bridge drive circuit is designed, comprising an H-bridge main circuit, the H-bridge main circuit including four MOS transistors: M1, M2, M3, and M4; and two independent clamping protection circuits respectively connected to the gates of the lower MOS transistors M3 and M4 of the H-bridge main circuit. The clamping protection circuits include a first current source bias circuit for controlling the pull-up capability and a second current source bias circuit for controlling the pull-down capability. TG switching tubes are respectively provided at the output ends of the first current source bias circuit and the second current source bias circuit.

[0005] Preferably, the circuit designed in the present invention also includes other technical features, wherein the first current source bias circuit includes a first current source, the first current source is connected to p3, p4, n1, n2, p3 and p4 form a PMOS current mirror, n1 and n2 form an NMOS current mirror, and p4 is connected to the first output end, the first current source bias circuit includes a second current source, the second current source is connected to p1, p2, n3, n4, p1 and p2 form a PMOS current mirror, n3 and n4 form an NMOS current mirror, and n4 is connected to the second output end, and the first output end and the second output end are respectively provided with a tg switch tube.

[0006] Preferably, the circuit designed in the present invention also includes other technical features, wherein the clamping protection circuit also includes an operational amplifier, and the operational amplifier is connected to the first output terminal of p4 and the second output terminal of n4.

[0007] Preferably, the circuit designed in the present invention also includes other technical features, wherein the first current source bias circuit includes p3, p4, n1, and n2 MOS tubes, and its amplification factor is determined by the product of the ratio of the number of MOS tubes p3 to p4 and the ratio of the number of MOS tubes n1 to n2.

[0008] Preferably, the circuit designed in the present invention also includes other technical features, wherein the second current source bias circuit includes p1, p2, n3, and n4 MOS tubes, and its amplification factor is determined by the product of the ratio of the number of MOS tubes p1 to p2 and the ratio of the number of MOS tubes n3 to n4.

[0009] Compared with the prior art, the utility model has the following advantages:

[0010] Through the arrangement of the present invention, it is only necessary to use a current source to construct a clamping voltage to protect the transistors in the H-bridge circuit, thereby reducing the overcharging of the circuit by the freewheeling current and not relying on the sampling voltage or other voltages. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 , is the overall structural diagram of the utility model;

[0012] Figure 2 , is a partial structural diagram of location A of the present utility model;

[0013] Figure 3 , is the current overcharge waveform diagram before the protection of the utility model is adopted;

[0014] Figure 4 , is the current overcharge waveform after adopting the protection of the utility model. DETAILED DESCRIPTION

[0015] In order to make the purpose, principle and structure of the present invention more clear, it is further described below with reference to the accompanying drawings and specific embodiments.

[0016] See also Figure 1 、 Figure 2. The utility model provides an H-bridge drive circuit with clamping protection, which uses two current sources as bias currents. The current flowing through it remains unchanged. One current source is amplified by a mirror image and passes through p3, p4, n1, and n2. The amplification factor is the product of the ratio of the number of MOS tubes of p3 and p4 and the ratio of the number of MOS tubes of n1 and n2. The amplification factor determines the pull-up capability of the p4 tube. The other current source is amplified by the current mirrors p1, p2, n3, and n4. The amplification factor is the product of the ratio of p1 and p2 and the ratio of the number of MOS tubes of n3 and n4, which determines the pull-down capability of the n4 tube. When the pull-up capability is greater than the pull-down capability to a certain extent, the lower left tube M3 is driven to be weakly turned on, thereby reducing the overcharging of the circuit by the freewheeling current. To ensure proper conduction of the lower left and right transistors, two TG switches are added to the output for control, separating the clamping voltage from the normal voltage. When the output is low, the switch connected to the output is disconnected, while the other switch is turned on, outputting a high level and ensuring normal conduction of the lower left transistor M3. When the output is high, the switch connected to the output is closed, while the other switch is disconnected, outputting a clamping voltage that weakly conducts the lower left transistor M3. This technology is simpler than other technologies, requiring only a current source to create a clamping voltage, without relying on sampling voltage or other voltages.

[0017] The principle of this utility model is:

[0018] Two clamping protection circuits are connected to the gates of the lower transistors of the H-bridge. When the lower left and upper right transistors are conducting, the freewheeling phase (when the upper left and lower right transistors are conducting) causes the lower left transistor to conduct weakly. When the upper left and lower right transistors are conducting, the freewheeling phase (when the lower left and upper right transistors are conducting) causes the lower right transistor to conduct weakly. The circuit remains conducting normally at all other times. In a traditional H-bridge, assume that the upper left transistor M1 and the lower right transistor M4 are conducting, while the other MOS transistors are off. Current flows from right output terminal 2 to left output terminal 1. After switching control, the lower left transistor M3 and the upper right transistor M2 are conducting. Due to the characteristics of the intermediate inductor, the current direction cannot change suddenly. Instead, the current flows from ground to right output terminal O2, left output terminal O1, and the power supply. Right output terminal O2 generates a negative voltage relative to ground, and the voltage at left output terminal O1 exceeds the power supply voltage, causing current to flow back into the power supply. After the switching control, the clamping protection circuit will control the MOS tube to be weakly turned on. At this time, part of the freewheeling current will flow from the lower left tube M3 to the ground, and the original freewheeling current will be reduced, effectively preventing the impact on the power supply voltage. Figure 3 、 Figure 4 .

[0019] The above description is only a specific implementation method of this utility model, but the protection scope of this utility model is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by this utility model, can make equivalent substitutions or changes based on the technical solutions and new concepts of this utility model, which should be covered by the protection scope of this utility model.

Claims

1. An H-bridge driving circuit with clamping protection, comprising an H-bridge main circuit, wherein the H-bridge main circuit comprises four MOS transistors: M1, M2, M3, and M4, characterized in that: Also includes: Two independent clamping protection circuits are connected to the gates of MOS tubes M3 and M4 under the H-bridge main circuit respectively. The clamping protection circuit comprises: The first current source bias circuit is used to control the pull-up capability, The second current source bias circuit is used to control the pull-down capability. The output ends of the first current source bias circuit and the second current source bias circuit are respectively provided with tg switching tubes.

2. The H-bridge driving circuit with clamping protection according to claim 1, characterized in that: The first current source bias circuit includes a first current source, which is connected to p3, p4, n1, and n2. P3 and p4 form a PMOS current mirror, n1 and n2 form an NMOS current mirror, and p4 is connected to the first output terminal. The first current source bias circuit includes a second current source, which is connected to p1, p2, n3, and n4. P1 and p2 form a PMOS current mirror, n3 and n4 form an NMOS current mirror, and n4 is connected to the second output terminal. The first output terminal and the second output terminal are respectively provided with a tg switch tube.

3. The H-bridge driving circuit with clamping protection according to claim 2, characterized in that: The clamping protection circuit further includes an operational amplifier connected to the first output terminal of p4 and the second output terminal of n4.

4. The H-bridge driving circuit with clamping protection according to claim 1, characterized in that: The first current source bias circuit includes MOS transistors p3, p4, n1, and n2, and its amplification factor is determined by the product of the ratio of the number of MOS transistors p3 to p4 and the ratio of the number of MOS transistors n1 to n2.

5. The H-bridge driving circuit with clamping protection according to claim 1, characterized in that: The second current source bias circuit includes MOS transistors p1, p2, n3, and n4, and its amplification factor is determined by the product of the ratio of the number of MOS transistors p1 to p2 and the ratio of the number of MOS transistors n3 to n4.

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