To study the feasibility of a shallow-depth neutrino detector, a Cosmic Muon Veto Detector (CMVD) is being built around the mini-ICAL detector at the IICHEP in Madurai, India. The CMVD will use extruded plastic scintillators for muon detection and wavelength-shifting fibers coupled with silicon photomultipliers (SiPMs) for signal readout. A power supply source is needed for biasing the SIPMs, where the accuracy, precision, and stability of the source are crucial to ensure consistent gain characteristics. We developed a biasing power supply circuit capable of sourcing 50-58V in 50 mV steps and up to 1mA of current. It features digital voltage adjustment and stabilization, as well as current monitoring capabilities using an external controller such as microcontrollers. In addition to providing better flexibility, the controller enables possibilities such as temperature compensation. Designed to power multiple SiPMs, this circuit can be easily integrated with the front-end electronics of SiPMs.