L293D H-bridge driver is the most commonly used driver for Bidirectional motor driving applications. The image below depicts the example application circuit and the logic for driving the motor in two directions.
The L293D has 4-half H-bridge drivers, which can be used to drive 2-DC motors bidirectionally. Here we are demonstrating how to drive a single DC motor using Half bridges 1 & 2. The DC motor is connected between OUT1 and OUT2 pins, and the pin IN1 is connected to the Microcontroller PWM output and pin IN2 is connected to a Microcontroller I/O port.
Clockwise rotation: To rotate the motor in clockwise direction the IN2 pin is made LOW and a PWM signal is generated on IN1 pin.
Anti-Clockwise rotation: To rotate the motor in clockwise direction the IN2 pin is made HIGH and a PWM signal is generated on IN1 pin.
Note: The pulse durations for Clockwise and anticlockwise rotations are opposite. i.e., if T is the period of the PWM. FOR 100 RPM in clockwise direction, Ton = 0.3T, & Toff = 0.7T & IN2 = LOW FOR 100 RPM in anticlockwise direction, Ton = 0.7T, & Toff = 0.3T & IN2 = HIGH