LM2596S 3A Constant Current Constant Voltage Buck Converter Module

The 3A LM2596S Buck module is a DC-to-DC step-down converter that combines adjustable constant-voltage (CV) and constant-current (CC) regulation in a single compact board. It is built around the LM2596S switching regulator from Texas Instruments, a 150kHz fixed-frequency PWM buck controller capable of delivering up to 3A of output current. The module accepts an input voltage from 7V to 35V DC and produces an output adjustable from 1.25V to 30V DC, with the requirement that the input voltage remain at least 1.5V above the desired output. Two onboard multi-turn potentiometers allow independent setting of the output voltage and the current limit, making the module suitable for both general-purpose voltage regulation and current-sensitive loads such as high-power LEDs and battery charging circuits.

In constant-voltage mode, the module behaves as a conventional adjustable buck regulator, holding the output voltage steady as the load varies. In constant-current mode, the module limits the output current to a user-set threshold, which protects LEDs from overcurrent and allows the module to serve as a simple CC/CV charger for lithium and lead-acid batteries. The board uses an SS36 Schottky diode for reverse protection and achieves a conversion efficiency above 92%, with output ripple held to a maximum of 50mV. Voltage regulation is specified at ±2.5%, and the module operates across a temperature range of -40°C to +85°C.

The 3A LM2596S 3A buck converter module measures 48mm × 23mm × 14mm and is suited to solar battery chargers, high-power LED drivers, constant-current power supplies, automotive electronics, and projects that require a non-standard voltage rail. Because the output current is limited to 3A, sustained loads above roughly 2A benefit from additional airflow or heat sinking. The module is a practical building block for bench supplies, LED lighting, battery charging, and embedded power systems where both voltage and current need to be controlled.