How to Use HLK-LD2451: Examples, Pinouts, and Specs

The HLK-LD2451 is a compact and efficient AC-DC power supply module manufactured by Hi-Link. It is designed to convert a wide range of AC input voltages (85-265V AC) into a stable 5V DC output. This module is ideal for powering low-power electronic devices and is widely used in IoT applications, embedded systems, and home automation projects. Its small size and high efficiency make it a popular choice for space-constrained designs.

• Powering microcontrollers (e.g., Arduino, ESP8266, ESP32)
• IoT devices and smart home systems
• Low-power sensors and modules
• Industrial control systems
• Consumer electronics

The HLK-LD2451 module is designed to provide reliable and efficient power conversion. Below are its key technical specifications:

The HLK-LD2451 module has six pins for input and output connections. The table below describes each pin:

1. Connect the AC Input:

   • Connect the AC IN (L) pin to the live wire of the AC power source.
   • Connect the AC IN (N) pin to the neutral wire of the AC power source.
   • Ensure proper insulation and safety precautions when working with high-voltage AC.

2. Connect the DC Output:

   • Use the +5V pin to power your device or circuit.
   • Connect the GND pin to the ground of your circuit.

3. Mounting:

   • Secure the module on a PCB or enclosure to prevent movement or accidental contact.
   • Ensure adequate spacing between the high-voltage AC side and the low-voltage DC side.

4. Testing:

   • Verify the output voltage using a multimeter before connecting it to your device.
   • Ensure the load does not exceed the maximum output current of 450mA.

• Safety First: Always handle the module with care when working with AC voltage. Use proper insulation and avoid touching the module while it is powered.
• Heat Dissipation: Although the module is efficient, ensure proper ventilation to prevent overheating, especially in high-temperature environments.
• Load Requirements: Do not exceed the maximum output current of 450mA to avoid damaging the module.
• Isolation: Maintain sufficient isolation between the AC and DC sides to prevent electrical hazards.

The HLK-LD2451 can be used to power an Arduino UNO directly. Below is an example circuit and code to blink an LED using the module:

1. Connect the +5V pin of the HLK-LD2451 to the 5V pin of the Arduino UNO.
2. Connect the GND pin of the HLK-LD2451 to the GND pin of the Arduino UNO.
3. Connect an LED to pin 13 of the Arduino UNO with a 220-ohm resistor in series.

// Simple LED Blink Example
// This code blinks an LED connected to pin 13 of the Arduino UNO.

void setup() {
  pinMode(13, OUTPUT); // Set pin 13 as an output
}

void loop() {
  digitalWrite(13, HIGH); // Turn the LED on
  delay(1000);            // Wait for 1 second
  digitalWrite(13, LOW);  // Turn the LED off
  delay(1000);            // Wait for 1 second
}

1. No Output Voltage:

   • Cause: Incorrect AC input connections or no input power.
   • Solution: Verify the AC input connections and ensure the power source is active.

2. Overheating:

   • Cause: Insufficient ventilation or excessive load.
   • Solution: Ensure proper airflow around the module and reduce the load to within the specified limit.

3. Output Voltage Fluctuations:

   • Cause: Unstable AC input or excessive load.
   • Solution: Use a stable AC power source and ensure the load does not exceed 450mA.

4. Module Not Working:

   • Cause: Damage due to incorrect wiring or overloading.
   • Solution: Inspect the module for visible damage and replace it if necessary.

Q1: Can the HLK-LD2451 power a Raspberry Pi?
A1: No, the HLK-LD2451 provides a maximum current of 450mA, which is insufficient for most Raspberry Pi models.

Q2: Is the module safe for use in home automation projects?
A2: Yes, the module is certified for safety (CE, RoHS) and is commonly used in home automation systems. However, ensure proper insulation and mounting.

Q3: Can I use the HLK-LD2451 with a 12V DC input?
A3: No, the HLK-LD2451 is designed to work with an AC input voltage range of 85-265V. It cannot operate with a DC input.

Q4: What happens if I exceed the maximum output current?
A4: Exceeding the maximum output current may cause the module to overheat or fail. Always ensure the load is within the specified limit.

Q5: Can I use this module outdoors?
A5: The HLK-LD2451 is not weatherproof. If used outdoors, it must be enclosed in a weatherproof housing.