Driving LEDs in LCD backlight

摘要

A backlight driver includes current sources that are connected between LED strings and a number of bias voltages. There can be any number of different bias voltages, each at a ground potential or higher voltage. The bias voltage is selected for a particular LED string in order to reduce a current drop across the current source. This reduces the power consumption of the current source and LED string. Heat dissipation is also reduced.

主权项

1. A system comprising:
a first voltage input, second voltage input, and third voltage input; a first voltage generator circuit, coupled to the first voltage input and generating a first voltage output, wherein the first voltage output is at a higher voltage level than the first voltage input; a first source block comprising a first source node, coupled to a first end of a first plurality of serially-connected light emitting diodes; and a first multiplexing block coupled to the second and third voltage inputs, and a first multiplexing block output is coupled to the first source block, wherein the first voltage output and the first source node are configured to be coupled to a second end of the first plurality of serially-connected light emitting diodes.