Patent ID: 6791306
Filing Date: 2004-09-14
Classification: H02M

Abstract:
For use with a DCâ€”DC voltage generator having a controller which generates a pulse width modulation (PWM) switching signal that switchably controls operation of a switching circuit containing first and second electronic switching devices coupled between respective power supply terminals, and having a common node thereof coupled through an inductor to a regulated voltage output terminal, a method of controlling generation of said PWM switching signal comprising the steps of:(a) coupling said common node to a first input of a transconductance amplifier and coupling said regulated voltage output terminal to a second input of said transconductance amplifier, said transconductance amplifier providing at an output thereof an inductor voltage-representative current proportional to the voltage across said inductor, and supplying said inductor voltage-representative current to a capacitor to produce a ripple waveform; (b) coupling said ripple waveform produced in step (a) to a first input of a hysteretic comparator, having an output controls the generation of said PWM switching signal, and comparing the output voltage at said output voltage terminal with a prescribed DC reference voltage to produce an error voltage, and coupling said error voltage to a second input of said hysteretic comparator.