Patent ID: 7701150

Claim:
A system that creates a desired current level within a traffic signal, comprising: a power supply unit that receives an external power signal and transforms the power signal to a lamp current; a pulse generator that generates current pulses and superimposes them onto the lamp current, wherein the pulse generator includes, an under voltage circuit that includes a peak detector and one or more voltage comparators for monitoring the lamp current signal to determine if the voltage of the lamp current signal is below a predetermined threshold; a frequency divider that consists of a voltage divider network and a counter which divides a clock value and outputs a counter signal, the clock value is the frequency of the lamp current signal; a current pulser that generates rectangular current pulses at a frequency based at least in part on the decade counter signal; a current sink that superimposes the square current pulse onto the lamp current and outputs a combined power signal to the alternating current (AC) line; and wherein the clock of the frequency divider circuit, the current pulser and the current sink are disabled when the line voltage is below a predetermined threshold.