AOKIN HW-212 DC-DC Buck Converter Module User Manual

Introduction

The AOKIN HW-212 is a versatile DC adjustable constant voltage and constant current step-down power supply module. Featuring an LCD display, it provides real-time readings of input voltage, output voltage, current, and power. This module allows for adjustable stable output voltage and current, making it suitable for various applications including a general buck power supply, battery charger, and LED constant current driver. It is designed for efficiency and practicality in DIY electronics projects.

Applications:

• Ordinary power supply
• Battery charger
• LED drive power
• Instrument voltage display
• Test meter
• Circuit testing
• Power conversion

Package Contents

The HW-212 module is supplied as a DIY kit and requires assembly. Please verify all components are present:

• 1x HW-212 5A Step Down Power Supply Module
• 1x 20*14*6mm Heat Sink
• 2x Acrylic Shell pieces
• 4x Blue Button Caps
• 4x M3*15mm Copper Columns
• 4x M3*8+6mm Copper Columns
• 8x M3*5mm Screws

Image: HW-212 DC-DC Buck Converter module with included assembly components (heat sink, acrylic case, standoffs, screws, button caps).

Product Features

• High voltage resistant terminals
• High quality acrylic shell for protection (requires assembly)
• Complete disability output support
• Anti-reverse protection
• Short circuit protection
• Enable output function
• HD LCD screen display
• Charging function support
• Selectable output display
• Display of input voltage
• Display of output voltage, current, and power
• Working status indicator LEDs
• Simultaneous display of multiple parameters
• High current capability with low heat generation

Specifications

Image: Dimensions of the HW-212 module.

Controls and Indicators

Image: HW-212 module controls and indicators.

• Long Press: Refers to holding a button for more than 3 seconds.
• ON/OFF Button:
  • Short Press: Toggles output voltage ON/OFF.
  • Long Press: Restores default settings for the next power cycle.
• IN/OUT Button:
  • Short Press: Switches display between input voltage and output voltage.
  • Long Press: Switches display between output current and output power.
• '+' Button: Regulates output voltage.
  • Short Press: Increases output voltage by 0.05V.
  • Long Press: Continuously increases output voltage (0.1V, then 1V increments).
• '-' Button: Regulates output voltage.
  • Short Press: Decreases output voltage by 0.05V.
  • Long Press: Continuously decreases output voltage (0.1V, then 1V increments).
• ADJ-I Potentiometer: Adjusts output current. Rotate clockwise to increase the output current. The module enters constant current (CC) mode if the load current reaches the set value, and the red CC LED indicator will illuminate.
• ON LED (Green): Output indicator. Illuminates when there is an output at the output terminals.
• CC LED (Red): Constant current output indicator. Illuminates when the module is operating in constant current mode (load current reaches the set current).
• FULL LED (Green): Charged fully indicator. Illuminates when a connected battery is fully charged (output current is less than 0.2A when the set current is 2A).
• CHAR LED: Charging indicator. Illuminates when charging is in progress.

Setup and Operation

1. As an Ordinary Step-Down Power Module

1. Connect the appropriate input voltage to the input terminals (IN+ and IN-).
2. Adjust the '+' and '-' constant voltage buttons to set the desired output voltage.
3. Initially, rotate the ADJ-I potentiometer counterclockwise for more than 10 turns.
4. Use a multimeter (set to 10A or 20A range) to test the output short-circuit current by connecting its probes to the module's output terminals (OUT+ and OUT-).
5. Rotate the ADJ-I constant current potentiometer clockwise to set the desired output current limit (overcurrent protection value).
6. Connect your load and begin using. For example, if the multimeter shows a maximum output current of 2A, the module will limit the current to 2A. The red CC LED will turn ON if the output current reaches 2A.
7. Note that the output voltage may slightly decrease due to the current sampling resistor at the output; this voltage drop increases with higher current.

2. As a Battery Charger

Important Considerations for Charging:

• A power module used as a charger must support constant current (CC) function to prevent excessive charging current that could damage the battery, especially when the battery voltage is low. The module should charge in CC mode until a certain level, then switch to constant voltage (CV) charging.
• Determine the floating charge voltage and maximum charge current for your battery. For example, a 3.7V/2200mAh lithium battery typically has a float charge voltage of 4.2V and a maximum charging current of 1C (2200mA).

1. Connect the appropriate input voltage to the input terminals. Do not connect the battery (load) during parameter setup.
2. Use a multimeter to measure the output voltage and adjust the '+' and '-' buttons to set the output voltage to the battery's required floating charge voltage (e.g., 4.2V for a 3.7V lithium battery).
3. Initially, rotate the ADJ-I potentiometer counterclockwise for more than 10 turns.
4. Use a multimeter (set to 10A or 20A range) to test the output short-circuit current by connecting its probes to the module's output terminals.
5. Rotate the ADJ-I constant current potentiometer clockwise to set the desired charge current value.
6. Connect the battery to the output terminals (OUT+ and OUT-) to begin charging.

3. As a High Power LED Constant Current Driver

1. Determine the LED's working current and maximum working voltage.
2. Connect the appropriate input voltage to the input terminals. Do not connect the LED (load) during parameter setup.
3. Use a multimeter to measure the output voltage at the output terminals and adjust the '+' and '-' buttons to set the output voltage to the LED's maximum working voltage.
4. Initially, rotate the ADJ-I potentiometer counterclockwise for more than 10 turns.
5. Use a multimeter (set to 10A or 20A range) to test the output short-circuit current by connecting its probes to the module's output terminals.
6. Rotate the ADJ-I constant current potentiometer clockwise to set the desired LED working current.
7. Connect the LED to the output terminals (OUT+ and OUT-) and test.

Important Notes

• The default output voltage is approximately 5V.
• This is a step-down power supply module; the output voltage must always be lower than the input voltage for normal operation.
• If there is no output voltage, repeatedly press the '-' button.
• This is a DC power module and cannot be connected to AC power.
• Do not short-circuit the output terminals.
• The input voltage must be at least 0.5V higher than the desired output voltage.
• When using as a charger, connect the input power before connecting the battery, and ensure the output voltage is higher than the battery voltage. It is recommended to add an anti-backflow diode in series at the input positive terminal.
• 'IN-' and 'OUT-' terminals cannot be connected together, as this will disable the constant current output function.
• Ensure the input power source can supply more power than the load requires.
• If the module becomes hot during operation, reduce the output power.
• The module's output voltage and current accuracy are 0.1V and 0.05A, respectively.
• Always read and understand this manual before use.

User Tips

No specific user tips were available from reviews or Q&A. General advice for electronic modules includes:

• Always double-check wiring before applying power to prevent damage.
• Use appropriate gauge wires for the expected current to avoid voltage drop and overheating.
• Consider adding external cooling (e.g., a fan) if operating at the upper limits of current/power, even with the included heat sink.
• When adjusting current limits, use a dummy load or a short-circuit test with a multimeter (as described in the "Setup and Operation" section) to accurately set the limit before connecting sensitive loads.

Troubleshooting

No specific troubleshooting steps were available from Q&A. Here are some general troubleshooting tips:

• No Output Voltage:
  • Check input power supply: Ensure it is within the specified working voltage range (DC 6.5V-36V) and correctly connected.
  • Verify input voltage is higher than desired output voltage (at least 0.5V higher).
  • Press the '-' button repeatedly to ensure the output is not set to a very low value or disabled.
  • Check for short circuits at the output.
• Output Current Not Reaching Desired Value:
  • Ensure the ADJ-I potentiometer is adjusted correctly (clockwise) to set the current limit.
  • Verify the load resistance is appropriate for the desired current and voltage.
  • Check if the module is overheating; if so, reduce the load or improve cooling.
  • Ensure 'IN-' and 'OUT-' are not connected together if constant current output is desired.
• Module Overheating:
  • Ensure the heat sink is properly installed.
  • Reduce the output current or power.
  • Provide adequate ventilation around the module.
• Inaccurate Readings:
  • The module has a specified accuracy of +/-0.1V for voltage and +/-0.05A for current. If readings are significantly off, verify with a calibrated multimeter.
  • Ensure good connections to avoid measurement errors due to contact resistance.

Maintenance

• Keep the module clean and free from dust and debris.
• Ensure proper ventilation to prevent overheating.
• Avoid exposing the module to moisture or extreme temperatures outside its operating range.
• Regularly check connections for tightness and corrosion.
• If the acrylic shell is used, ensure it is securely fastened to protect the circuitry.

Warranty and Support

For warranty information or technical support, please contact the seller or manufacturer directly. Keep your purchase receipt as proof of purchase.