App-Notes » Circuit Design » L293D Motor Driver IC: Pinout, Applications, and Circuits

L293D Motor Driver IC: Pinout, Applications, and Circuits

motor driver h bridge motor control robotics circuit design

The L293D is a widely used motor driver IC that allows you to control DC motors in both directions. This dual H-bridge motor driver can drive up to two motors independently and provides bidirectional current flow, making it ideal for robotics and various motor control applications.

Features of the L293D Motor Driver IC

Here’s a look at some of the key features of the L293D:

  • Dual H-Bridge: Can control two DC motors independently, allowing forward and reverse direction control.
  • Maximum Operating Voltage: 36V, with an output current of 600 mA per channel.
  • Peak Output Current: 1.2A per channel (for a short duration).
  • Enable Pins: Allows turning each motor on or off without altering the control logic.
  • Thermal Shutdown Protection: Protects against overheating, enhancing durability.
  • Diode Protection: Internal flyback diodes prevent damage from back-EMF generated by the motors.
  • 4 Input Pins: Provides flexibility for controlling motor speed and direction using PWM and logic signals.

L293D Pinout Diagram

The L293D IC comes in a 16-pin package, with two sets of pins dedicated to controlling each motor.

L293D pin diagram

Figure 1: L293D Motor driver IC pin diagram for N/NE package. Check the datasheet for DWP package.

The following table describes the function of each pin:

Pin NumberNameDescription
1Enable 1,2Enables/Disables Motor A. Connect to HIGH for enabling the motor.
2Input 1Logic input to control Motor A direction.
3Output 1Connects to one terminal of Motor A.
4, 5GNDGround pins for power stability.
6Output 2Connects to the other terminal of Motor A.
7Input 2Second logic input to control Motor A direction.
8Vcc2Motor voltage supply (up to 36V) for motor operation.
9Enable 3,4Enables/Disables Motor B. Connect to HIGH for enabling the motor.
10Input 3Logic input to control Motor B direction.
11Output 3Connects to one terminal of Motor B.
12, 13GNDGround pins for power stability.
14Output 4Connects to the other terminal of Motor B.
15Input 4Second logic input to control Motor B direction.
16Vcc1Logic voltage supply (typically 5V) for IC logic operation.

Working Principle

Here’s a breakdown of how the L293D works:

  • Bidirectional Motor Control: Each motor can be driven in both directions by controlling the combination of HIGH and LOW signals on the input pins (IN1, IN2 for Motor A, and IN3, IN4 for Motor B).
  • PWM Speed Control: By applying a PWM signal to the Enable pins (EN1 for Motor A and EN2 for Motor B), motor speed can be controlled by adjusting the duty cycle.

Application Example: Controlling a Robot Car’s Movement

The L293D is commonly used in robotic applications to control the movement of a two-wheeled robot car. Here’s how it can control both forward and backward motion:

  • Circuit Setup: Connect two DC motors to the outputs (OUT1 & OUT2 for Motor A and OUT3 & OUT4 for Motor B). Apply motor power to the VCC2 pin, logic voltage to VCC1, and connect all ground pins to the system ground. Enable both motors by connecting Enable 1,2 and Enable 3,4 to a logic HIGH signal or PWM signals for speed control.

  • Direction Control: Set IN1 HIGH and IN2 LOW to move Motor A forward; reversing this will change the direction. Similarly, control IN3 and IN4 for Motor B.

  • Programming the Microcontroller: The microcontroller can control motor directions by toggling IN1, IN2, IN3, and IN4, while applying PWM to the Enable pins for speed variation.

Other Applications

The L293D isn’t just limited to robotics. Here are a few other applications where you might find it:

  • Conveyor Belts: L293D can control small conveyor systems used in assembly lines.
  • RC Vehicles: Commonly used for bidirectional speed control in remote-controlled cars.
  • Robotic Arms: Enables precise movement control of robotic arms by managing motor rotation direction and speed.

Conclusion

The L293D IC simplifies motor control in embedded systems by efficiently managing both direction and speed. Its H-Bridge configuration, built-in protection features, and compatibility with microcontrollers make it ideal for various applications in robotics and automation.