Low-overhead current generator for lighting circuits

摘要

This application relates to a lighting system comprising a plurality of light emitting diode, LED, circuits, and a power source for providing a drive voltage to the plurality of LED circuits. For each LED circuit, the lighting system comprises a first variable resistance element connected between the respective LED circuit and ground, and a first feedback circuit configured to control a voltage at a first node between the respective LED circuit and the respective first variable resistance element to a first voltage. The lighting system further comprises a current source and a second variable resistance element connected between the current source and ground, wherein each first variable resistance element is configured to attain a resistance value depending on a resistance value attained by the second variable resistance element.

主权项

1. A lighting system comprising:
a light emitting diode, LED, circuit; a power source for providing a drive voltage to the LED circuit; and a programmable current source connected between the LED circuit and ground and configured to output an output current in accordance with a digital input code representing a numerical value, wherein the programmable current source comprises switching means for performing a switching operation in accordance with the digital input code; and the switching means is adapted to switch a predetermined number of bits on the least significant bit, LSB, side of the digital input code in accordance with binary coding, and to switch a remaining number of bits on the most significant bit, MSB, side of the digital input code in accordance with unary coding.