Patent ID: 7948468
Filing Date: 2011-05-24
Classification: G09G,H05B

Abstract:
1. A system for controlling multiple LEDs, comprising: one or more parallel strings of one or more series LED(s); a voltage source capable of providing voltage to the parallel strings; and a phase shifted pulse width modulator capable of designating strings to be activated based at least in part upon an input command, wherein a percentage of the parallel strings are activated during a time period based at least in part upon the input command, wherein the voltage source further comprises a power supply, wherein the power supply is capable of outputting a relatively minimum power to activate the percentage of the parallel strings, wherein the phase shifted pulse width modulator is coupled to the power supply, wherein the phase shifted pulse width modulator is capable of providing a control signal to the power supply, wherein the power supply output is based at least in part upon the control signal from the phase shifted pulse width modulator, and wherein efficiency improvement due to voltage scaling may be described by: