DC-DC converter and voltage conversion method thereof

摘要

A DC-DC converter is provided. When a load of the DC-DC converter is too light, the DC-DC converter can raise a frequency of its PWM signal, and reduce a pulse width of the PWM signal, so as to avoid the frequency of the PWM signal falling into a frequency range that can heard by human's ear and maintain high conversion efficiency of the DC-DC converter.

主权项

1. A direct current (DC)-DC converter, comprising:
an adjustment module, outputting a second pulse width modulation (PWM) signal according to a first PWM signal and an output voltage of the DC-DC converter; an output module, coupled to the adjustment module, and providing the output voltage in response to the second PWM signal; and a control module, coupled to the adjustment module and the output module, for detecting a frequency of the first PWM signal or the second PWM signal, wherein when the frequency of the first PWM signal or the second PWM signal is lower than a predetermined frequency, the control module outputs a control signal to control the output module to pull down the output voltage, so that the first PWM signal is generated earlier, and controls the adjustment module to reduce a pulse width of the second PWM signal.