Circuitry and methods for driving a plurality of LED strings are disclosed herein. In one embodiment, the circuitry comprises a plurality of current regulating circuits electrically coupled to the LED strings and are configured to regulate a current flowing through the LED strings. At least two control circuits are coupled to the current regulating circuits and are configured to generate a control signal according to terminal voltages of the corresponding current regulating circuits. A voltage converter is electrically coupled to the LED strings and to the at least two control circuits, and is configured to regulate the DC driving voltage according to the at least two control signals.