PWM modulation assembly of H-bridge drive circuit

Abstract

The invention provides a PWM modulation assembly of an H-bridge drive circuit. Four switch tubes of the H-bridge drive circuit are NMOS tubes. Gates of the switch tubes are respectively connected withthe drive circuit; the input end of the drive circuit is connected with the signal output end of an H-bridge drive signal generation circuit; the H-bridge drive signal generation circuit continuouslyoutputs a conduction signal to the drive circuit corresponding to an upper tube on one side, continuously outputs a cut-off signal to the drive circuit corresponding to a lower tube on the other side, and alternately outputs cut-off and conduction signals to the drive circuits corresponding to an upper tube and a lower tube on the other side. According to the modulation assembly, the upper tube on the first side is always in a conduction state, and large parasitic capacitance exists between the grid electrode of the upper tube on the first side and the power supply voltage, so that the storage capacitance of a boost circuit is greatly reduced; and the upper tube on the first side is conducted, and the lower tube on the first side is cut off, so that the output end of the H-bridge drive circuit cannot generate negative voltage, and the circuit works more reliably than before.

Description

technical field

[0001] The invention relates to an H bridge drive circuit, in particular to a PWM modulation component of the H bridge drive circuit. Background technique

[0002] Integrated H-bridge driver chips are widely used in DC brushless motors. In the traditional H-bridge drive circuit designed with integrated circuit technology, the upper tube of the H-bridge generally uses a PMOS tube, and the lower tube of the H-bridge generally uses an NMOS tube. When the withstand voltage and area are equal, the on-resistance of the PMOS transistor is much larger than that of the NMOS transistor. In applications where the driving current is large and the on-resistance is required to be small, using a PMOS tube as the upper tube of the H-bridge requires a very large area to achieve a small on-resistance, which makes the chip cost high and packaging difficult. This leads to the fact that in the case of high-current applications, the general H-bridge is implemented with discrete ...

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