Patent ID: 7592791
Filing Date: 2009-09-22
Classification: H02M,Y02B

Abstract:
1. A direct current to direct current (DC-DC) converter comprising: a pair of switches; a load capacitor operatively connected to said pair of switches; a pulse width modulator adapted to generate pulse signals for driving said pair of switches; an analog comparator with hysteresis adapted to control an output voltage level within a specified range, wherein as said output voltage level rises above a high threshold level, an analog comparator output becomes low and starts skipping clock pulses, wherein as said output voltage level drops below a low threshold level, said analog comparator output becomes high and a clock signal is passed to said pair of switches to charge said load capacitor, and wherein said analog comparator is further adapted to compare said output voltage level with either said low threshold level or said high threshold level; a first counter; a first register operatively connected to said first counter, wherein when said analog comparator output becomes low said first counter stops and stores its last value Non in said first register; a first digital comparator operatively connected to said first register; and an up-down counter operatively connected to said first digital comparator and said pulse width modulator, wherein during turn-on of said pair of switches, a load current at a load resistor is supplied by said pair of switches, and said load capacitor charges, wherein a turn-on time is a time when said output voltage level discharges from said low threshold level to said high threshold level through said load capacitor, wherein said turn-on time is measured by said first counter and said first register, wherein said first counter starts counting when said analog comparator output becomes high, which occurs when said output voltage level reaches said low threshold level and said pair of switches turn on, and wherein when said output voltage level reaches said high threshold level, said analog comparator output becomes low and said first counter stops counting and stores its last value, which represents the measured turn-on time, in said first register.