Patent ID: 8730698

Claim:
A power conversion controller for controlling the operation of a switch in a power conversion circuit, wherein the power conversion controller is configured to operate the switch according to: a variable frequency mode of operation for switching frequencies greater than a minimum threshold value, wherein the variable frequency mode of operation is a first boundary conduction mode of operation with valley switching only or a second boundary conduction mode of operation with valley switching and additional valley skipping, wherein the power conversion controller is configured to transit between the first boundary conduction mode of operation and the second boundary conduction mode of operation based on a maximum switching frequency; and a fixed frequency mode of operation at a switching frequency equal to the minimum threshold value, wherein the power conversion controller is configured to transit between the fixed frequency mode of operation and the variable frequency mode based on a minimum switching frequency, wherein the power conversion controller comprises: an AND logic module; an OR logic module connected to an output terminal of the AND logic module; a flipflop module connected to an output terminal of the OR logic module; a first signal generation module having the maximum switching frequency and connected to an output terminal of the flipflop module and an input terminal of the AND logic module; and a second signal generation module having the minimum switching frequency and connected to the output terminal of the flipflop module and an input terminal of the OR logic module.