Patent ID: 8653756

Claim:
An electronic circuit for driving a plurality of series connected light emitting diode strings with a controllable DC-DC converter, the electronic circuit comprising: a plurality of current regulators, each having a respective input node and a respective output node, the input node or the output node coupled to an end of a respective one of the plurality of series connected light emitting diode strings, wherein each current regulator is configured to pass a respective predetermined current through the respective one of the plurality of series connected light emitting diode strings to which it is coupled; and a plurality of error amplifiers, each having a respective input node and a respective output node, wherein each one of the plurality of input nodes of the plurality of error amplifiers is coupled to the input node or the output node of a respective one of the plurality of current regulators, wherein the output nodes of the plurality of error amplifiers are coupled to a junction node, wherein the plurality of error amplifiers is configured to generate an error signal at the junction node.