9A DC-DC Step Down Module – Precision voltage and current control for demanding projects
Whether you are powering a high-output LED, charging LiPo batteries, or building a custom bench power supply, the challenge is always the same: matching your available power source to your specific requirements. This adjustable step-down module is the perfect solution, efficiently converting any input between 5V and 40V into the exact voltage you need with laboratory-grade precision.
Note: For output currents exceeding 7A, we recommend active cooling with a fan. To add reverse polarity protection, simply install an external Schottky diode on the input line.
Why choose this module? (Key Advantages):
- 25-turn multi-turn potentiometers — Achieve fine, granular adjustments for both voltage and current without sudden jumps; ideal for sensitive battery chemistry or precision LED lighting.
- 95% efficiency — With 95% of power delivered to your load, the heatsink stays cool during standard operation, ensuring energy efficiency and long-term reliability.
- Independent CC/CV control — Features constant current and constant voltage modes, making it an excellent smart charger for LiPo, Li-Ion, or NiMH batteries without needing extra circuitry.
- Integrated short-circuit protection — Automatically cuts output if a short is detected, keeping your connected devices safe.
- Compact 65 × 48 mm footprint — Designed with 4 mounting holes (3 mm) for quick and easy integration into any DIY enclosure or control panel.
Performance and Specifications
At the heart of this module is a high-speed buck (step-down) converter, engineered to maintain a rock-solid output voltage even under fluctuating loads. With an input voltage range of 5V to 40V DC, it is highly versatile, supporting multi-cell LiPo batteries, PC power supplies, bench power units, or low-voltage solar panels.
The dual 25-turn potentiometers provide precise control over the output voltage (1.2V–35V) and current limit (0.2A–9A). While the module boasts an impressive 95% efficiency, we recommend adding a small cooling fan to the heatsink if you are running continuous loads above 7A.
| Parameter | Specification |
|---|---|
| Input Voltage | 5V – 40V DC |
| Adjustable Output Voltage | 1.2V – 35V DC |
| Max Input Current | 9A |
| Adjustable Output Current | 0.2A – 9A |
| Peak Efficiency | 95% |
| Adjustment Type | Multi-turn potentiometers (25 turns) – Voltage & Current |
| Protection | Short-circuit (Reverse polarity via external diode) |
| Cooling Requirement | Active (fan) for currents > 7A |
| Board Dimensions | 65 × 48 × 24 mm |
| Mounting | 4 screws, Ø 3 mm holes |
| Converter Type | Buck (Step Down) DC-DC |
Usage and Setup Instructions
- Connect your power source to the input terminals, ensuring correct polarity (+ and –). The input voltage should be at least 1.5V higher than your desired output voltage.
- Adjust the output voltage using the potentiometer marked V-ADJ. Turn slowly—the 25-turn design allows for high precision. Verify the output with a multimeter.
- Set the current limit using the I-ADJ potentiometer. Connect your load and adjust until the desired limit is reached, monitoring the current with an ammeter in series.
- Monitor temperatures during high-load operation. If the current exceeds 7A, attach a fan to the heatsink or directly over the board components.
- Install a Schottky diode (e.g., SB1040 or equivalent) on the positive input line if you require protection against accidental reverse polarity.
Package Contents
- 1x Adjustable DC-DC Step Down Module 5-40V / 9A
Frequently Asked Questions
Can I use this to charge a 3.7V LiPo battery from a 12V source?
Yes. Simply set the output voltage to 4.2V (the maximum for a single-cell LiPo) and limit the current to the manufacturer’s recommended charging rate. The module’s CC/CV capability is perfect for battery charging.
Is a cooling fan always required?
No. Active cooling is only necessary when the output current consistently exceeds 7A. Below this threshold, the 95% efficiency ensures the module runs at a safe, comfortable temperature.
How can I protect the module against incorrect wiring?
The module does not have internal reverse polarity protection. We recommend installing a Schottky diode (such as an SB1040) in series on the positive input line; it is an inexpensive way to prevent damage from accidental connection errors.
Does this work as a high-power LED driver?
Yes. Set the current to the LED’s nominal rating and the voltage to the required forward voltage. The adjustable current limiting makes it an efficient, all-in-one driver solution.
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