Patent ID: 7638950

Claim:
A system comprising: a first power potential supplying a voltage; a second power potential; a light source have a power supply side and a power return side; a power node connected to the power supply side of the light source; a current switch connected between the power return side of the light source and the second potential, the current switch including an input to receive a current switch control signal to place the switch in one of an ON state and an OFF state allowing current to flow through the current switch in the ON state; and a preconditioner circuit connected to the first power potential and the power node, the precondtioner circuit including an input to receive a preconditioner control signal to place the preconditioner circuit in one of an ON state and an OFF state, wherein the preconditioner circuit supplies the voltage to the power node in its ON state and effectively eliminates the voltage to the power node in its OFF state; a processing device to generate the current switch control signal and the preconditioner control signal; and wherein the preconditioner control signal includes a pulse having a longer duration than a corresponding pulse of the current control signal and is timed to pulse high before the current control signal pulses high and is timed to pulse low after the current control signal pulses low.