Patent ID: 8773038
Filing Date: 2014-07-08
Classification: H05B,Y02B

Abstract:
1. A circuit for controlling a plurality of LEDs coupled in series, the circuit comprising: a switching converter operable as a current source to be coupled to the plurality of LEDs to provide a constant load current thereto, the switching converter including an inductor to be coupled in series with the plurality of LEDs such that when the LEDs are coupled, the same load current flows through the inductor and the plurality of LEDs; a plurality of floating driver circuits, each floating driver circuit to be coupled in parallel to a respective individual LED of the plurality of LEDs, each floating driver circuit configured to fully or partially take over the load current thereby bypassing the respective LED in accordance with a respective modulated input signal to control the intensity of light emitted by the respective LED; and a modulator for each floating driver circuit, the modulator providing the modulated input signal supplied to the respective floating driver circuit, a duty cycle of the modulated input signal being dependent on input data received via an I/O interface.