Introduction to H-bridge drive for DC motor speed regulation

H-bridge driver

Search Name

H-Bridge

Introduction

The H-bridge is a typical DC motor control circuit. It is named "H-bridge" because its circuit shape resembles the letter H. Four transistors form the four vertical legs of the H, and the motor is the horizontal bar in the H (Note: the figure is only a simplified schematic diagram, not a complete circuit diagram, and the transistor drive circuit is not drawn).

This block represents an H-bridge motor driver. This block can be driven by PWM or average voltage.

In PWM mode, if the PWM port voltage is higher than the enable threshold voltage, the motor will be powered.

In Average Voltage Mode, the PWM port voltage divided by the PWM signal amplitude parameter defines the ratio of the on-time to the PWM period. Using this ratio and assumptions about the load, the module applies an average voltage to the load to achieve the correct average load current.

The simulation mode parameter values ​​must be the same for the controlled PWM voltage and the H-bridge module.

Parameter settings

1. simulation mode & load assumption

1. Power supply: internal

2. Simulation mode: pwm

2. input thresholds

3. Enable threshold voltage

4. PWM signal amplitude

5. Reverse threshold voltage

6. Braking threshold voltage

7. bridge parameters

8. Output voltage amplitude

9. Total bridge on resistance

10. Freewheeling diode on resistance

Pinout

PWM: pwm signal input terminal (or average voltage)

REF: Reference voltage (ground)

REV: Direction control terminal: If the REV port voltage is greater than the reverse threshold voltage, the output voltage polarity is reversed.

BRK: Braking control terminal If the BRK terminal voltage is greater than the braking threshold voltage, the output terminal will be short-circuited through a bridge arm connected in series with the parallel combination of the second bridge arm and the freewheeling diode.

+ terminal: positive output terminal

- terminal: negative output terminal

Test Circuit

Voltage sensor package:

Related parameter settings

PWM generator:

H-bridge driver

Waveform