Patent ID: 7288924
Filing Date: 2007-10-30
Classification: H02M

Abstract:
1. A method for controlling a switch mode power supply which couples a power source to a load, the method comprising: operating at least one switch with a switching period T, wherein, during a given switching period, operating the at least one switch comprises operating the at least one switch with a first duty cycle D=t sampling a power supply input current at one or more sample times during the given switching period to obtain one or more sampled input current values, the one or more sample times synchronized with respect to the time t=t determining an estimate of a median input current I determining an estimate of an average input current I determining a new duty cycle D based at least in part on the estimate of the average input current I operating the at least one switch with the new duty cycle D during a subsequent switching period; wherein operating the at least one switch with the new duty cycle D causes the average input current I in,avg to track a desired average input current I in,avg,des .