How to Use XH-M131: Examples, Pinouts, and Specs

The XH-M131 is a DC-DC buck converter module manufactured by Easyware. It is designed to step down a higher input voltage to a lower, adjustable output voltage, making it ideal for powering devices that require a stable and regulated power supply. The module also features adjustable current limiting, which adds an extra layer of protection for sensitive components.

• Powering low-voltage devices from a higher-voltage source (e.g., 12V to 5V).
• Battery charging applications with adjustable current control.
• LED driver circuits.
• DIY electronics projects requiring a regulated power supply.
• Arduino and microcontroller-based systems.

The XH-M131 module is equipped with robust features to ensure reliable performance in various applications. Below are its key technical specifications:

The XH-M131 module has the following input and output terminals:

1. Connect the Input Voltage:

   • Connect the VIN+ terminal to the positive terminal of your power source.
   • Connect the VIN- terminal to the ground of your power source.
   • Ensure the input voltage is within the range of 5V to 36V DC.

2. Connect the Output Load:

   • Connect the VOUT+ terminal to the positive terminal of your load or device.
   • Connect the VOUT- terminal to the ground of your load.

3. Adjust the Output Voltage:

   • Use the onboard potentiometer labeled "CV" (Constant Voltage) to adjust the output voltage.
   • Turn the potentiometer clockwise to increase the voltage and counterclockwise to decrease it.

4. Set the Output Current Limit:

   • Use the potentiometer labeled "CC" (Constant Current) to set the maximum output current.
   • This is particularly useful for protecting sensitive devices or for battery charging applications.

5. Power On and Test:

   • After making all connections, power on the module and measure the output voltage and current using a multimeter to ensure proper settings.

• Heat Dissipation: For currents above 2A, ensure proper heat dissipation by attaching a heat sink to the module.
• Input Voltage: Always ensure the input voltage is at least 1.5V higher than the desired output voltage.
• Polarity: Double-check the polarity of the input and output connections to avoid damage to the module.
• Load Testing: Before connecting sensitive devices, test the output voltage and current with a dummy load.

The XH-M131 can be used to power an Arduino UNO from a 12V power source by stepping down the voltage to 5V. Below is an example circuit and code:

• Connect the VIN+ terminal of the XH-M131 to the positive terminal of a 12V DC power source.
• Connect the VIN- terminal to the ground of the power source.
• Adjust the output voltage to 5V using the CV potentiometer.
• Connect the VOUT+ terminal to the 5V pin of the Arduino UNO.
• Connect the VOUT- terminal to the GND pin of the Arduino UNO.

// Example code to blink an LED using Arduino UNO powered by XH-M131
// Ensure the XH-M131 output is set to 5V before connecting to the Arduino

const int ledPin = 13; // Pin connected to the onboard LED

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

void loop() {
  digitalWrite(ledPin, HIGH); // Turn the LED on
  delay(1000);                // Wait for 1 second
  digitalWrite(ledPin, LOW);  // Turn the LED off
  delay(1000);                // Wait for 1 second
}

1. No Output Voltage:

   • Cause: Incorrect input connections or insufficient input voltage.
   • Solution: Verify the polarity and ensure the input voltage is within the specified range.

2. Output Voltage Not Adjustable:

   • Cause: Faulty potentiometer or incorrect adjustment.
   • Solution: Check the CV potentiometer and ensure it is not damaged. Turn it slowly to adjust the voltage.

3. Overheating:

   • Cause: High output current without proper heat dissipation.
   • Solution: Attach a heat sink to the module and ensure adequate ventilation.

4. Load Not Powering On:

   • Cause: Current limit set too low.
   • Solution: Adjust the CC potentiometer to increase the current limit.

Q: Can the XH-M131 be used to charge batteries?
A: Yes, the module can be used for battery charging applications. Set the output voltage to match the battery's charging voltage and adjust the current limit to prevent overcharging.

Q: What is the maximum input voltage for the XH-M131?
A: The maximum input voltage is 36V DC. Exceeding this limit may damage the module.

Q: Can I use the XH-M131 to power a Raspberry Pi?
A: Yes, you can use the XH-M131 to step down voltage to 5V for powering a Raspberry Pi. Ensure the output voltage is precisely set to 5V and the current limit is sufficient for the Raspberry Pi's requirements.

Q: Is the XH-M131 protected against reverse polarity?
A: No, the module does not have built-in reverse polarity protection. Always double-check the polarity of your connections.