Patent ID: 7903058
Filing Date: 2011-03-08
Classification: G09G,H05B

Abstract:
1. A circuit for enabling efficient driving of a plurality of Light Emitting Diodes (LEDs), comprising: a high side monitoring circuit that is configured to determine a first time to switch between a first gain and a second gain to drive the plurality of LEDs with a plurality of current sources, the LEDs forming multiple parallel branches, each branch including at least one of the LEDs and coupled in series with one of the current sources, the high side monitoring circuit comprising a plurality of first transistors, each first transistor coupled to a different one of the current sources, the first transistors coupled together and configured to generate a voltage representative of a maximum forward voltage across the LEDs, the maximum forward voltage comprising a largest voltage across the LEDs in one of the branches; and a low side monitoring circuit that is configured to determine a second time to switch between the first gain and the second gain to drive the plurality of LEDs with a plurality of current sinks, each branch coupled in series with one of the current sinks, the low side monitoring circuit comprising a plurality of second transistors, each second transistor coupled to a different one of the current sinks, the second transistors coupled together and configured to generate a current representative of the maximum forward voltage.