MIKROE 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.

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 behaviour.

Because of that, the board’s operating range is defined by two factors. 1) maximum input voltage and current (should not exceed 20V/0.5A); and 2) maximum wattage arising from current and I/O voltage difference (should not exceed 1W, measured as I x (Input V - Output V).

The board also carries a MOSFET chip to toggle the output on and off.

VReg Click communicates with the target board MCU through the SPI interface (CS, SCK, MISO, MOSI). The board can use either a 3.3V or a 5V power supply.

It is also possible to use the board’s power supply as the Input, by resoldering the onboard INPUT SEL jumper.

• Interface: SPI
• Compatibility: mikroBUS™
• Dimensions: 57.15 x 25.4mm
• Input Voltage: 3.3V or 5V

• Schematic
• LM317M Datasheet
• GitHub