How to Use L6203 Full Bridge Driver: Examples, Pinouts, and Specs

The L6203 is a dual full-bridge driver manufactured by STMicroelectronics. It is specifically designed for driving inductive loads such as DC motors and stepper motors. The L6203 allows for precise control of motor direction and speed, making it ideal for applications requiring high current output and robust protection features. With built-in thermal shutdown, overcurrent protection, and high voltage operation, the L6203 is a reliable choice for motor control in industrial, automotive, and robotic systems.

• DC motor control for robotics and automation
• Stepper motor driving in CNC machines and 3D printers
• Industrial motorized actuators
• Automotive systems such as electric window lifters and wipers
• Home appliances requiring motorized components

The L6203 is available in a Multiwatt-11 package. Below is the pinout and description:

1. Power Supply: Connect a DC power supply (12V to 48V) to the VS pin. Ensure the supply voltage matches the motor's requirements.
2. Logic Inputs: Use the IN1 and IN2 pins to control the direction of the motor. These pins accept standard logic levels (0V for LOW, 5V for HIGH).
3. Enable Pin: Set the EN pin HIGH to activate the driver. When LOW, the driver is disabled, and the outputs are in a high-impedance state.
4. Motor Connections: Connect the motor terminals to the OUT1, OUT2, OUT3, and OUT4 pins, depending on the motor type (DC or stepper motor).
5. Heatsinking: Attach a heatsink to the L6203 to dissipate heat effectively, especially when driving high currents.
6. Protection Features: The L6203 includes built-in protection for thermal shutdown and overcurrent. Ensure proper circuit design to avoid triggering these protections unnecessarily.

Below is an example of how to control a DC motor using the L6203 and an Arduino UNO:

// Define pin connections
const int IN1 = 7;  // Connect to L6203 IN1 pin
const int IN2 = 8;  // Connect to L6203 IN2 pin
const int EN = 9;   // Connect to L6203 EN pin

void setup() {
  // Set pin modes
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(EN, OUTPUT);

  // Enable the L6203 driver
  digitalWrite(EN, HIGH);
}

void loop() {
  // Rotate motor in one direction
  digitalWrite(IN1, HIGH);  // Set IN1 HIGH
  digitalWrite(IN2, LOW);   // Set IN2 LOW
  delay(2000);              // Run motor for 2 seconds

  // Stop the motor
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, LOW);
  delay(1000);              // Pause for 1 second

  // Rotate motor in the opposite direction
  digitalWrite(IN1, LOW);   // Set IN1 LOW
  digitalWrite(IN2, HIGH);  // Set IN2 HIGH
  delay(2000);              // Run motor for 2 seconds

  // Stop the motor
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, LOW);
  delay(1000);              // Pause for 1 second
}

• Decoupling Capacitors: Place a decoupling capacitor (e.g., 100µF electrolytic) near the VS pin to stabilize the power supply.
• Heatsinking: Ensure adequate heatsinking to prevent thermal shutdown during high-current operation.
• Current Sensing: Use the Vref pin for current sensing or limiting if required by your application.
• Logic Levels: Ensure the logic input levels are compatible with the L6203 (0V to 7V range).

1. Motor Not Spinning

   • Cause: The EN pin is not set HIGH.
   • Solution: Verify that the EN pin is connected to a HIGH logic level.

2. Driver Overheating

   • Cause: Insufficient heatsinking or excessive current draw.
   • Solution: Attach a proper heatsink and ensure the motor's current requirements are within the L6203's limits.

3. Motor Vibrates but Does Not Rotate

   • Cause: Incorrect logic input signals.
   • Solution: Verify the IN1 and IN2 signals. Ensure they are not both HIGH or both LOW simultaneously.

4. Thermal Shutdown Triggered

   • Cause: Prolonged high current or inadequate cooling.
   • Solution: Reduce the motor load or improve the heatsink design.

5. No Output Voltage

   • Cause: Faulty connections or undervoltage on the VS pin.
   • Solution: Check all connections and ensure the supply voltage is within the specified range.

• Can the L6203 drive stepper motors? Yes, the L6203 can drive stepper motors by controlling the two full bridges independently.

• What is the maximum current the L6203 can handle? The L6203 can handle up to 4A per bridge, provided proper heatsinking is used.

• Is the L6203 compatible with 3.3V logic? Yes, the L6203 accepts logic levels as low as 0V and as high as 7V, making it compatible with both 3.3V and 5V systems.

• Does the L6203 require external diodes for protection? No, the L6203 has built-in diodes for flyback protection, simplifying circuit design.

This concludes the documentation for the L6203 Full Bridge Driver. For further details, refer to the official datasheet provided by STMicroelectronics.