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US 9,439,252 B1Granted
Driving LEDs in LCD backlight
AssigneeIML International
InventorAlberto Viviani
Life of this patent
Estimating the term…
Abstract
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.
Claims20
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.
3 more elements
A method comprising:
- providing a first voltage input, second voltage input, and third voltage input;
- using 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;
- coupling a first source block comprising a first source node to a first end of a first plurality of light emitting diodes coupled in series;
- and
- coupling a first multiplexing block 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 light emitting diodes coupled in series.
3 more elements
A system comprising:
- a backlight comprising a first plurality of light emitting diodes coupled in series;
- 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 the first plurality of 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 light emitting diodes.
4 more elements
Dependencies are inferred from the claim text.