Patent ID: 7876059

Claim:
A system for controlling a matrix of light emitting diodes (LED) connected to an input line, the system comprising: a power converter for connecting to the matrix of LEDs and to the input line therebetween and for receiving from said input line an input current and an input voltage characterized by a shape and a frequency and for providing a direct current (D.C.) output for powering up the LEDs, yielding an operating current through the LEDs; said power converter including a first current sensor for sensing said input current and a second current sensor for sensing said operating current; a controller for connecting to both the input line and to said power converter; said controller including a voltage sensor for sensing said input voltage and a pre-regulator i) for receiving said operating current, said input current and said input voltage, ii) for biasing said operating current towards a target current value, and iii) for regulating said power converter to cause said input current to follow said shape and frequency of said input voltage, yielding a unity power factor and minimizing harmonic distortion of said input current.