Patent ID: 9209696
Filing Date: 2015-12-08
Classification: H02M,Y02B

Abstract:
1. A power controller for a switching mode power supply, wherein the switching mode power supply has a power switch connected in series with an inductive device, a voltage drop of the inductive device is capable of oscillating to generate at least one signal valley, and the power switch is controlled by a PWM signal defining an ON time and an OFF time, the power controller comprising: a valley detector coupled to the inductive device, for providing a valley indication signal indicating the occurrence of the signal valley; a block time generator for providing a block time; and an OFF time controller, for recording an oscillation time record to provide a prior oscillation time, for concluding the OFF time in response to the oscillation time record, the block time, and the valley indication signal, and for updating the oscillation time record basing on a present oscillation time, wherein the prior oscillation time is in association with a previous switching cycle; wherein the present oscillation time starts after the voltage drop has oscillated and ends when the OFF time is concluded.