A digital device generates a fixed duty cycle signal with an internal oscillator after a Power-On-Reset (POR). This fixed duty cycle signal is output on a signal pin that normally is used for a PWM control signal. The fixed duty cycle signal is used to stimulate the voltage generation circuits so as to power up the digital device for initialization thereof. Once the digital device has powered-up and initialized, the digital device switches over to normal operation for control of the power system.