LM317 CC Mode

The LM317 is a versatile adjustable voltage regulator that can also be configured as a constant current regulator. In current regulation mode, it provides a stable, fixed current to a load regardless of fluctuations in supply voltage or load resistance, making it ideal for applications like battery charging and LED driving.

How the LM317 Works as a Current Regulator

The LM317 maintains a constant voltage of 1.25V between its output (Vout) and adjustment (Adj) terminals. This voltage can be used to create a constant current source by using a series resistor between the output pin (Vout) and the load.

Circuit diagram