How to Use SparkFun PicoBuck LED Driver: Examples, Pinouts, and Specs

The SparkFun PicoBuck LED Driver is an exceptionally versatile board designed to drive high-power LEDs with ease. It is capable of controlling up to three separate channels of LEDs and is suitable for a variety of lighting projects, from DIY home decor to industrial applications. The PicoBuck is popular for its simplicity and efficiency, accepting a wide range of input voltages and providing built-in PWM control for adjustable brightness.

• Architectural lighting
• Automotive and bicycle lights
• DIY home lighting projects
• Signage and display lighting
• Horticulture and grow lights
• Prototyping for industrial lighting solutions

• Input Voltage: 6V to 20V
• Output Current: Up to 350mA per channel (adjustable)
• Maximum Power Rating: 1W per channel
• PWM Control: Up to 20kHz
• Efficiency: Up to 95%
• Operating Temperature: -40°C to 85°C

1. Connecting Power: Connect a power supply to the VIN and GND pins, ensuring that the voltage is within the specified range (6V to 20V).
2. Attaching LEDs: Connect your high-power LEDs to the OUT1, OUT2, and OUT3 channels, with the anode to the output pin and the cathode to the common ground.
3. Enabling the Driver: Apply a high signal to the EN pin to enable the driver. A low signal will turn off all outputs.
4. Controlling Brightness: Connect a PWM signal to the PWM pin to adjust the brightness of the LEDs. The frequency can be up to 20kHz.

• Ensure that the total power does not exceed the maximum power rating of the board.
• Use proper heat sinking for the LEDs to prevent overheating.
• If dimming is not required, the PWM pin can be tied to VIN for full brightness.
• Avoid applying a voltage to the PWM pin that is higher than VIN to prevent damage.

// Define the PWM pin connected to the PicoBuck
const int pwmPin = 9; // Must be a PWM-capable pin

void setup() {
  // Set the PWM pin as an output
  pinMode(pwmPin, OUTPUT);
}

void loop() {
  // Increase brightness gradually
  for (int dutyCycle = 0; dutyCycle <= 255; dutyCycle++) {
    analogWrite(pwmPin, dutyCycle);
    delay(10);
  }
  // Decrease brightness gradually
  for (int dutyCycle = 255; dutyCycle >= 0; dutyCycle--) {
    analogWrite(pwmPin, dutyCycle);
    delay(10);
  }
}

• LEDs Not Lighting Up: Ensure that the power supply is connected correctly and that the EN pin is set high.
• Flickering LEDs: Check the PWM signal for proper frequency and ensure it is not exceeding the input voltage.
• Overheating: Make sure that the LEDs are properly heat-sinked and that the current settings do not exceed the LEDs' ratings.

• Double-check all connections for any loose wires or solder joints.
• Verify that the input voltage is stable and within the specified range.
• Use a multimeter to check the current through each LED channel.
• If using PWM control, ensure that the signal is clean and within the correct voltage range.

Q: Can I drive LEDs that require more than 350mA? A: No, the PicoBuck is designed to drive LEDs up to 350mA per channel. Exceeding this limit may damage the board or the LEDs.

Q: Is it possible to chain multiple PicoBuck boards together? A: Yes, you can chain multiple boards for additional channels, but ensure that each board has its own power connection and that the PWM signals are synchronized.

Q: How do I adjust the current limit for each channel? A: The current limit is set by onboard resistors. To adjust the current, you would need to change these resistors to the appropriate values based on the desired current limit.

Q: Can I use the PicoBuck without a PWM signal? A: Yes, if you do not require dimming, you can tie the PWM pin to VIN for constant full brightness.