A driving arrangement for a plurality of light emitting diodes (LEDs), the driving arrangement constituted of: a plurality of serially connected first LEDs coupled to a source voltage; a plurality of first electronically controlled switches, each associated with a particular one of the plurality of serially...http://www.google.se/patents/US8174212?utm_source=gb-gplus-sharePatent US8174212 - LED string driver with light intensity responsive to input voltage
