Patent ID: 8310849

Claim:
A pulse width modulation (PWM) regulator integrated circuit (IC), for controlling a duty cycle of at least one switch to convert an input voltage signal into an output voltage, comprising: a pin, for receiving an input signal different from the input voltage signal, wherein the input signal has a lasting time substantially the same as a time of the input voltage signal situated at a high level, but the input signal has a waveform different from that of the input voltage signal; a conversion unit, coupled to the pin, for converting the input signal into a square wave signal; and a PWM controller, for generating at least one PWM drive signal according to the square wave signal to control a duty cycle of the switch; wherein the PWM controller generates two PWM drive signals for controlling duty cycles of a high voltage switch and a low voltage switch respectively, the pin is a boost (BST) pin, and the input signal is a bootstrap high voltage signal for providing a voltage required for driving the high voltage switch.