Patent ID: 8779745

Claim:
A three-quarter bridge power converter circuit configured for providing regulated power to a load, comprising: a first switch configured to selectively couple a switch node to a higher voltage; a second switch configured to selectively couple the switch node to a lower voltage; a clamp voltage element configured to store a clamp voltage intermediate the higher and lower voltages; a bi-directional clamping switch configured to selectively couple the switch node to the voltage element when the first and second switches are not coupling the switch node to the higher and lower voltages, and thereby clamp the switch node to the clamp voltage; and a control circuit configured to generate control signals G 1 , G 2 , and G 3 to cooperatively switch respectively the first and second switches and the bi-directional clamping switch, including generating G 1 and G 2 based on values associated with switching frequency and duty cycle, converted to respectively a reference phase value related to the switching frequency, and a variable phase value related to both the switching frequency and the duty cycle, such that the reference phase value and the variable phase value have a predetermined resolution, the difference between the reference phase value and the variable phase value is used to generate the G 1 and G 2 control signals, the G 3 control signal is asserted to clamp the switch node to the clamp voltage when neither G 1 nor G 2 is asserted, such that the G 1 , G 2 and G 3 control signals provide a predetermined duty factor resolution.