Patent ID: 7106602
Filing Date: 2006-09-12
Classification: H02M,Y02B

Abstract:
1. A method of providing no-load to full-load regulation and reducing the power consumption under low-load or no-load conditions of a power converter in an open feedback loop system using a first switch to control current flow through the primary winding of a transformer, comprising the steps of: providing an output to a secondary winding of said transformer through self-oscillation; increasing the turn off time of the first switch at no-load via a second switch driven by a zener diode; maintaining said zener diode in conduction via a first capacitor charged by an auxiliary winding of the transformer; and maintaining conduction of said second switch using a very small control current so as to prolong the off time of said first switch such that a reduced duty cycle with longer off time of said first switch is maintained at no-load and to substantially reduce the difference between said output voltage under low-load or no-load and the corresponding output voltage under a full-load condition.