Patent ID: 8274266

Claim:
A power supply system for producing a regulated output voltage at an output node in response to an input voltage at an input node, comprising: an inductive device, a plurality of switching devices for providing connection of the inductive device to the input and output nodes and a ground node, a switch driver circuit for driving the switching devices so as to enable the power supply to operate in a boost mode to increase the input voltage, in a buck mode to decrease the input voltage, and in a solid-state flyback mode to transfer between the boost mode and the buck mode, and a duty cycle detection circuit for providing the switch driver circuit with a mode control signal based on a duty cycle of a signal for controlling switching of the switching devices, in the solid-state flyback mode, the switching devices being configured to provide switching of the inductive device between an input state in which the inductive device is connected between the input node and the ground node, and an output state in which the inductive device is connected between the ground node and the output node, wherein the duty cycle detection circuit is configured for comparing the duty cycle with first, second, third and fourth threshold levels Dth 1 , Dth 2 , Dth 3 and Dth 4 , respectively, where Dth 1 >Dth 2 >Dth 3 >Dth 4 .