Patent ID: 8358519

Claim:
A switch control circuit for controlling a bridge circuit comprising: an upper and a lower switch element, connected to a positive and a negative voltage, respectively, and comprising a flywheel diode connected in parallel with each switch element, an inductor connected between a junction of the switch elements and a load, and at least one capacitor connected between the load and any of said voltages, a drive circuit for controlling each switch element in order to switch off the corresponding switch element when a reference current has been obtained in the inductor and for switching on the corresponding switch element when the current in the inductor is essentially zero, a first timer circuit adapted to prevent the on-switch of one of the switch elements until a minimum time period has passed such that the maximum switching frequency of the bridge circuit is limited, wherein the first timer circuit is adapted to prevent the on-switch of said one of the switch elements until the minimum time period has passed from the previous on-switch of said one of the switch elements, a current comparator for comparing an inductor current with the reference current and for switching off said one of the switch elements when the inductor current exceeds the reference current, and a voltage comparator for switching on said one of the switch elements when the junction voltage exceeds a preset voltage.