Method and circuit for switching source modulation frequency

摘要

The DC to DC converter has an oscillator and generates an output voltage to drive a system. The modulation frequency is used for modulating a pulse width modulation (PWM) circuit in the DC to DC converter. The method includes steps of: 1. providing the modulation frequency from the oscillator; 2. switching the source of the modulation frequency from the oscillator to the system clock to provide the modulation frequency when the system is driven by the output voltage from the DC to DC converter; and 3. stopping the oscillator for reducing a power loss.