How to Use DC-DC 3.7..5v 12/5/8/9v BS02: Examples, Pinouts, and Specs

The DC-DC 3.7..5V 12/5/8/9V BS02 is a versatile DC-DC converter designed to step up or step down voltage levels efficiently. It is commonly used to convert a 3.7V input (e.g., from a lithium-ion battery) to various output voltages such as 12V, 5V, 8V, or 9V. This makes it ideal for powering a wide range of electronic devices, including microcontrollers, sensors, and small appliances.

• Powering microcontrollers like Arduino, ESP32, or Raspberry Pi.
• Supplying voltage to sensors, relays, and other peripherals.
• Portable electronics powered by lithium-ion batteries.
• DIY projects requiring multiple voltage levels.

• Input Voltage Range: 3.7V to 5V DC
• Output Voltage Options: 12V, 5V, 8V, 9V (selectable)
• Maximum Output Current: 1A (varies with output voltage)
• Efficiency: Up to 90% (depending on input/output voltage and load)
• Operating Temperature: -40°C to +85°C
• Dimensions: Compact module, typically 22mm x 17mm x 4mm
• Weight: ~5g

The DC-DC 3.7..5V 12/5/8/9V BS02 module typically has the following pins:

1. Connect the Input Voltage:
   • Attach the VIN pin to a 3.7V to 5V DC power source (e.g., a lithium-ion battery or USB power).
   • Connect the GND pin to the ground of the power source.
2. Select the Output Voltage:
   • Use the SEL pin to configure the desired output voltage. This is typically done by connecting the SEL pin to a specific resistor or jumper setting as per the module's datasheet.
3. Connect the Load:
   • Attach the VOUT pin to the device or circuit you want to power.
   • Ensure the load does not exceed the maximum output current (1A).
4. Power On:
   • Once all connections are secure, power on the input source. The module will regulate the voltage to the selected output level.

• Heat Dissipation: Ensure proper ventilation or heat sinking if the module operates near its maximum current capacity.
• Input Voltage Range: Do not exceed the specified input voltage range (3.7V to 5V) to avoid damaging the module.
• Output Voltage Selection: Refer to the module's datasheet for precise instructions on configuring the SEL pin for the desired output voltage.
• Load Compatibility: Verify that the connected load operates within the selected output voltage and current limits.

To power an Arduino UNO with 5V output from the module:

1. Connect the VIN pin to a 3.7V lithium-ion battery.
2. Set the SEL pin to configure the output voltage to 5V.
3. Connect the VOUT pin to the Arduino's 5V pin and the GND pin to the Arduino's GND.

Here is an example Arduino code to blink an LED while powered by the DC-DC converter:

// Simple LED blink example for Arduino UNO
// Ensure the DC-DC converter is set to output 5V for the Arduino UNO.

const int ledPin = 13; // Built-in LED pin on Arduino UNO

void setup() {
  pinMode(ledPin, OUTPUT); // Set LED pin as 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 voltage or loose connections.
   • Solution: Verify that the input voltage is within the 3.7V to 5V range and all connections are secure.

2. Overheating:

   • Cause: Excessive load or poor ventilation.
   • Solution: Reduce the load current or improve ventilation around the module.

3. Incorrect Output Voltage:

   • Cause: Misconfigured SEL pin or faulty module.
   • Solution: Double-check the SEL pin configuration and ensure it matches the desired output voltage.

4. Load Not Powering On:

   • Cause: Load requires more current than the module can provide.
   • Solution: Ensure the load's current requirements are within the module's 1A limit.

• Can I use this module with a 3.3V input? No, the input voltage must be between 3.7V and 5V for proper operation.

• How do I select the output voltage? Refer to the module's datasheet for specific instructions on configuring the SEL pin.

• What happens if I exceed the maximum current? The module may overheat, shut down, or become damaged. Always ensure the load current is within the 1A limit.

• Can I use this module to power a Raspberry Pi? Yes, but ensure the output voltage is set to 5V and the current requirements of the Raspberry Pi are met.