How to Use L293D Motor Driver: Examples, Pinouts, and Specs

The L293D is a dual H-bridge motor driver IC designed to control the direction and speed of DC motors and stepper motors. It is capable of driving two motors simultaneously, making it an essential component in robotics, automation, and motor control projects. The IC can handle bidirectional control of motors, allowing for forward and reverse motion, and supports PWM (Pulse Width Modulation) for speed control.

• Robotics (e.g., controlling wheels or robotic arms)
• Automation systems
• Conveyor belts
• Remote-controlled vehicles
• Stepper motor control in CNC machines or 3D printers

The L293D is a robust and versatile IC with the following key specifications:

The L293D comes in a 16-pin DIP (Dual Inline Package). Below is the pinout and description:

1. Power Connections:

   • Connect Vcc1 (Pin 16) to the logic voltage (e.g., 5V for Arduino).
   • Connect Vcc2 (Pin 8) to the motor supply voltage (e.g., 9V or 12V, depending on the motor).
   • Connect all GND pins (Pins 4, 5, 12, 13) to the ground of the power supply.

2. Motor Connections:

   • Connect the motor terminals to the output pins (Output 1 and Output 2 for Motor 1, Output 3 and Output 4 for Motor 2).

3. Control Logic:

   • Use the input pins (Input 1, Input 2, Input 3, Input 4) to control the direction of the motors.
   • Enable the H-bridges using the Enable pins (Enable 1,2 for Motor 1, Enable 3,4 for Motor 2).

4. PWM for Speed Control:

   • Apply a PWM signal to the Enable pins to control motor speed.

Below is an example of how to control a single DC motor using the L293D and Arduino UNO:

• Connect Vcc1 to the Arduino's 5V pin.
• Connect Vcc2 to an external 9V power supply.
• Connect GND to the Arduino's GND pin.
• Connect Input 1 to Arduino pin 9.
• Connect Input 2 to Arduino pin 10.
• Connect Enable 1,2 to Arduino pin 11.
• Connect the motor terminals to Output 1 and Output 2.

// Define motor control pins
const int enablePin = 11; // Enable pin for Motor 1
const int input1Pin = 9;  // Input 1 for Motor 1
const int input2Pin = 10; // Input 2 for Motor 1

void setup() {
  // Set motor control pins as outputs
  pinMode(enablePin, OUTPUT);
  pinMode(input1Pin, OUTPUT);
  pinMode(input2Pin, OUTPUT);

  // Initialize motor to stop
  digitalWrite(input1Pin, LOW);
  digitalWrite(input2Pin, LOW);
  analogWrite(enablePin, 0); // Set speed to 0
}

void loop() {
  // Rotate motor forward at 50% speed
  digitalWrite(input1Pin, HIGH);
  digitalWrite(input2Pin, LOW);
  analogWrite(enablePin, 128); // PWM value for 50% speed
  delay(2000); // Run for 2 seconds

  // Rotate motor backward at full speed
  digitalWrite(input1Pin, LOW);
  digitalWrite(input2Pin, HIGH);
  analogWrite(enablePin, 255); // PWM value for 100% speed
  delay(2000); // Run for 2 seconds

  // Stop the motor
  digitalWrite(input1Pin, LOW);
  digitalWrite(input2Pin, LOW);
  analogWrite(enablePin, 0); // Set speed to 0
  delay(2000); // Wait for 2 seconds
}

• Ensure the motor voltage (Vcc2) matches the motor's rated voltage.
• Do not exceed the maximum current rating of 600mA per channel.
• Use a heat sink if the IC becomes too hot during operation.
• Always connect all ground pins to a common ground.

1. Motor Not Running:

   • Check if the Enable pin is set to HIGH.
   • Verify the power supply connections (Vcc1, Vcc2, and GND).
   • Ensure the input pins are receiving the correct logic signals.

2. Motor Running in the Wrong Direction:

   • Swap the logic levels on the input pins (e.g., HIGH on Input 1 and LOW on Input 2).

3. IC Overheating:

   • Ensure the motor's current draw does not exceed 600mA.
   • Use a heat sink or reduce the load on the motor.

4. PWM Not Controlling Speed:

   • Verify that the PWM signal is applied to the Enable pin.
   • Check the PWM frequency and duty cycle settings in your code.

Q: Can the L293D drive stepper motors?
A: Yes, the L293D can drive stepper motors by controlling the sequence of inputs to the H-bridges.

Q: Can I use the L293D with a 3.3V microcontroller?
A: Yes, but ensure that the logic voltage (Vcc1) is compatible with the microcontroller's output levels.

Q: What is the difference between L293 and L293D?
A: The L293D includes internal flyback diodes for protection, while the L293 does not.

Q: Can I control more than two motors with one L293D?
A: No, the L293D can control only two motors. For more motors, use additional L293D ICs.