The LM317-M IC is a reliable regulator with typical line regulation of 0.01% and load regulation of 0.1%. It also has internal short-circuit current limiting and thermal overload protection. The circuit regulates voltage by turning all input/output difference into heat (effectively dissipating all the excess power). If it gets too hot it may damage the board or cause unexpected behavior.
VReg click is a digitally controlled DC Voltage regulator in mikroBUS™ form factor. The design is based on the well-known LM317-M circuit, with the addition of a 12-bit DAC, 12-bit ADC, and an Operational Amplifier. Two pairs of screw terminals serve as inputs and outputs.