Could anyone please explain to me how the H-bridge in the picture works?

cocca

Could anyone please explain to me how the H-bridge in the picture works? [Copy link]

[;)] The picture is in the attachment.
Thanks!

rain

The H-bridge actually acts as a power amplifier in the circuit. By turning the MOSFET on and off in a certain sequence, the motor moves one step. The L/R time constant of each coil determines the rise time of the current. Slow rise times (usually the case with induction motors) will reduce performance. Adjusting the width of the current pulse can improve performance, so many motor control chips often include pulse-width modulation (PWM) circuits. These chips measure the voltage drop across the resistor in series with each coil and adjust the duty cycle of the pulses driving each coil. This method - similar to a switch-mode power supply - improves the efficiency of stepper motors. The H-bridge drives one coil in a DC motor or stepper motor. The controller (not shown) turns the MOSFET on and off to generate current. The PWM circuit uses the voltage in the sensitive resistor to determine the optimal MOSFET "on" period.

chenggaoyu

The PWM circuit uses the voltage across the sense resistor to determine the optimum MOSFET "on" period.