This article discussed how to create a negative power supply using either a switching regulator (buck) or a charge pump. Schematics were presented along with equations, so that designers can determine the best solution to meet their own requirements. Negative power supply. It is common for Internet of Things (IoT) devices, industrial sensors, meters, precision, and medical equipment to require both a positive and negative voltage. Often, these voltages must be symmetrical and sourced from a single power supply. 3V or 5V), negative voltage remains critical for specific applications such as operational amplifiers, RS232 communication, and GaN (Gallium Nitride) transistor biasing. +15V, 0V, -15V for example, vs 30V, 0V.