LM2596 DC-DC Buck Converter Module with LED Voltmeter Display

LM2596 DC-DC Buck Converter Module with LED Voltmeter Display is an adjustable step-down switching voltage regulator board based on the LM2596S-ADJ IC, enhanced with an onboard 3-digit 7-segment LED digital voltmeter and tactile control buttons. Accepting a 4.0V to 40V DC input and delivering a continuously adjustable 1.25V to 37V DC output at up to 2A continuous (3A peak), it allows users to monitor either input or output voltage in real time without an external multimeter.

Key Features:

• Integrated 3-Digit LED Voltmeter: Bright 0.28-inch 7-segment red LED display reads 0V–40V with ±0.1V resolution and self-powers from inputs ≥4.0V.
• One-Touch Input / Output Voltage Toggle: Right-hand tactile button switches the voltmeter readout between Input Voltage (IN LED lit) and Output Voltage (OUT LED lit), or turns the display off.
• Wide 4V–40V Input to 1.25V–37V Output: Steps down 12V, 24V, or 36V DC buses to 3.3V, 5V, 9V, 12V, or any custom voltage via the multi-turn 3296 potentiometer.
• Screw Terminal + Solder Pad Connectivity: Includes dual 2-pin 5.08mm screw terminal blocks alongside large IN+/IN- and OUT+/OUT- solder pads for tool-free lab wiring.
• Up to 3A Peak Current & Thermal Protection: Delivers 2A continuously (up to 3A with an added heatsink) with internal thermal shutdown and current limiting.

Technical Specifications:

• Regulator IC: LM2596S-ADJ 150kHz Step-Down Switching Regulator (TO-263-5L)
• Input Voltage Range: 4.0V to 40.0V DC (VIN must be ≥ 1.5V higher than VOUT)
• Output Voltage Range: 1.25V to 37.0V DC Continuously Adjustable
• Output Current: 2.0A Continuous / 3.0A Peak (Attach heatsink above 15W / 2A)
• Conversion Efficiency: Up to 92%
• Switching Frequency: 150 kHz
• Voltmeter Accuracy: ± 0.1V (User-calibratable via onboard button menu)

Mechanical Specifications:

• PCB Material: FR-4 Double-Sided Fiberglass Board with M3 Corner Mounting Holes
• Connectors: 2 × 2-Pin Screw Terminal Blocks + 4 × Solder Pads
• Controls: 3296W Multi-Turn Trimmer Potentiometer + Tactile Mode Switch

Dimensions:

• Length: 66 mm (or 56 mm compact variant)
• Width: 35 mm
• Height: 14 mm
• Weight: ~22 g

Pinout and Wiring:

• IN+ / IN- (Input Terminal): Connect 4.0V–40V DC power source (observe polarity strictly).
• OUT+ / OUT- (Output Terminal): Regulated 1.25V–37V DC step-down output.
• Mode Button: Short press switches voltmeter display between Input and Output voltage; long press turns the LED display off to save standby power.
• Potentiometer: Turn screw clockwise/counterclockwise (up to 15 turns on first use) to set output voltage.

Datasheet Reference:

• Primary IC Datasheet: Texas Instruments LM2596 Simple Switcher 3A Step-Down Voltage Regulator Datasheet (PDF)

Commonly Used in:

• DIY Variable Benchtop Lab Power Supplies
• 12V/24V Vehicle & Industrial to 5V/9V/12V Step-Down Converters
• 3D Printer (24V to 12V Noctua Cooling Fan) Voltage Reducers
• Solar Panel to Battery / Microcontroller Buck Regulation

Applications:

• Steps down a 24V 3D printer power supply to a quiet 12V rail for hotend and electronics cooling fans while displaying exact fan voltage.
• Serves as a compact variable 1.25V–35V bench power supply when powered from an old 19V laptop charger or 24V SMPS.
• Monitors 12V/24V vehicle or robotics battery voltage on the IN display while supplying regulated 5V to an Arduino or Raspberry Pi on the OUT terminals.

Equivalent Models:

• LM2596S DC-DC Buck Converter Adjustable Step-Down Power Supply Module: Compact 43mm × 21mm version without the onboard LED voltmeter.
• XL4015 5A Step-Down Adjustable Buck Power Supply with LED Voltmeter: Higher-current 5A (75W) buck converter with LED voltmeter.

Package Includes:

• 1 × LM2596 DC-DC Buck Converter Module with LED Voltmeter Display