The module has onboard constant voltage (CV) and constant current (CC) control feature which is useful for general purpose power supply and battery charger applications.
There are two multiturn trimpots to adjust the output voltage and output current. Further, there are three LED indicators – the first one near the input connector is the constant-current (cc) indicator, while next two LEDs are intended mainly for battery charging applications (battery charging and battery full indicators). 
Slowly turning the voltage adjustment (V-ADJ) trimpot clockwise will raise the output voltage gradually, and a counterclockwise rotation will lower it. Likewise, clockwise turning of the current adjustment (I-ADJ) trimpot increases the current limit while counterclockwise action decreases the current limit. It’s advised to adjust the voltage level at first, and then the current level.
The heart of the module is a XL4015 chip which is a 180 KHz fixed frequency PWM step-down (buck) DC/DC converter, capable of driving a 5A load with high efficiency, low ripple and excellent line and load regulation.
 An over current protection function is built inside so that when a short circuit occurs, the operation frequency will be reduced to 48KHz. 
 
SPECIFICATION AND FEATURES
Type: Buck, Step Down
Voltage
Input: 8 to 34V
Output: 1.25 to 32V
Regulation: ± 2.5%
Adjustable output current: 5A maximum
Power: 75W
Operating frequency: from 48KHz to 180KHz
Load Regulation: Average ±0.5%
Efficiency: 96%
Protection
Short circuit: Yes, up to 8A
Overheating: Yes, Automatically turns off the output
Reverse polarity protection: None
Operating temperature: -40°C to 85°C
Dimensions: 26mm x 52mm x 15.5mm