This technical brief describes a microcontroller-based soft-start controller for power supplies in systems with multiple voltages. Sometimes applications have devices with multiple voltage requirements (such as core voltages and I/O voltages). The sequence in which these voltages rise is important. A common requirement is that one voltage must rise and stabilize before another voltage. The circuit described in this document operates by using Pulse Width Modulation (PWM) to slowly increase the amount of time the power supply is allowed to operate.