Abstract: A system and method for providing a constant current source driver for a light emitting diode string. The converter includes a current sensor that derives feedback signal corresponding to a peak current through the light emitting diode string. The feedback signal is used by a controller to vary a duty cycle of the controller to regulate the average current. The controller is operable to regulate the average current as the number of light emitting diodes is increased and/or decreased.

Abstract: A system and method for providing a constant current source driver for a light emitting diode string. The converter includes a current sensor that derives feedback signal corresponding to a peak current through the light emitting diode string. The feedback signal is used by a controller to vary a duty cycle of the controller to regulate the average current. The controller is operable to regulate the average current as the number of light emitting diodes is increased and/or decreased.

Abstract: A power supply circuit includes: a switching flyback transformer having a primary winding and a secondary winding; a current transformer having a primary winding and a secondary winding; and a switching transistor have a conduction path and a control terminal. The primary winding of the switching flyback transformer, the primary winding of the current transformer and the conduction path of the switching transistor are coupled together in a series circuit. The switching flyback transformer and the current transformer share a common core. The windings of the switching flyback transformer may be wound around one leg of the common core, while the windings of the current transformer may be wound around a different leg of the common core.