Driver circuit for at least one load and method of operating the same

Abstract

A driver circuit (1) for operating at least one load, such as a LED unit (7) is provided, comprising an input (2) for receiving an input voltage (V IN) from a power supply (6), an output (3) for providing an output voltage (V OUT) to said load and a switching converter (4) with at least a storage inductor (11) connected with a switching device (13), said switching converter (4) being disposed to generate an average output current by sequential switching operation of said switching device (13) between at least a charging mode and a discharging mode. Furthermore, a switching controller (5) is connected with said switching device (13) to control the switching operation of said switching device (13) and comprises a feedback inductor (24), inductively coupled to said storage inductor (11) to provide a feedback voltage, corresponding to the variation of an inductor current (I S) through said storage inductor (11) and a voltage compensation circuit (25), connected with said feedback inductor (24) to determine at least one compensation signal from said feedback voltage, said compensation signal corresponding to said input voltage (V IN) or said output voltage (V OUT). To provide a cost-efficient and versatile driver circuit (1), the switching controller (5) is configured to at least control said switching device (13) between said discharging and said charging mode in dependence on said inductor current (I s) and to control a duty cycle of the switching operation in dependence on said at least one compensation signal, so that in case of a variation of said input (V IN) or output voltage (V OUT), said average output current, provided to the load, is maintained substantially constant.

Dependencies are inferred from the claim text.