Novel H bridge driving circuit

Abstract

The invention provides a novel H bridge driving circuit. The novel H bridge driving circuit comprises a power source end VCC, a grounding end GND, a first driving module and a second driving module, wherein the first driving module comprises a transistor NM1, a clamp circuit, a transistor NM2, a boost circuit and a control circuit, the transistor NM2 and the transistor NM1 are sequentially connected in series between the power source end VCC and the grounding end GND, the transistor NM2 is an NMOS tube, the boost circuit, the transistor NM1, the transistor NM2 and the clamp circuit are connected with the control circuit, the boost circuit is connected with the power source end VCC and the transistor NM2, and the clamp circuit is connected with the transistor NM1. The novel H bridge driving circuit is advantaged in that a pull-up tube of a traditional H bridge driving circuit is replaced by the NMOS tube from a PMOS tube, and conduction resistance of the whole H bridge driving circuit is reduced.

Description

technical field [0001] The invention relates to the field of circuits, in particular, the invention relates to a novel H-bridge drive circuit. Background technique [0002] H-bridge is a typical DC motor control circuit, because its circuit shape resembles the letter H, so it is named "H-bridge", such as figure 1 Shown is a conventional H-bridge circuit, it is worth noting that, figure 1 It is just a schematic diagram, not a complete circuit diagram. [0003] The circuit of the traditional H-bridge includes 4 vertical legs, wherein Q1 and Q3 form a group, and Q2 and Q4 form a group. The specific working principle is as follows: [0004] When Q1 and Q3 are turned on, the load current flows out from the power supply VCC and flows through A to B. At this time, point A of the load terminal is at a positive potential relative to point B, and the motor rotates forward; [0005] When the motor rotates at a certain angle, in order to ensure that the direction of the motor remain...

AI Technical Summary

Problems solved by technology

[0006] It is worth mentioning that there are two shortcomings in the traditional H-bridge drive circuit. One is that most of the traditional H-bridge drive circuits use PMOS transistors, such as figure 1 Q1 and Q2 in the circuit are used as pull-up tubes, and the carriers of the PMOS tube are holes, and the carriers of the NMOS tube are free electrons, and the mobility of electrons is about 3 times that of holes. Therefore, the conductivity of the PMOS tube The on-resistance is much larger than that of the NMOS tube; the second is to consider the existence of the parasitic inductance of the DC motor. Therefore, when the traditional H-bridge drive circuit changes the current direction, the current of the parasitic inductance can easily impact the power supply, resulting in damage to the entire drive circuit.

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