Patent ID: 8427074

Claim:
A power line controller for controlling a ballast dimming level of an electronic ballast connected to receive an AC power signal from an AC power line, comprising: a signal pattern circuit operable to produce a dimming level information signal having a signal pattern associated with a desired ballast dimming level; a transformer coupled to the signal pattern circuit, the transformer having a transformer coil; first and second output terminals configured to connect the transformer coil in series with the AC power line so that a ballast control signal associated with the dimming level information signal is inserted on the AC power signal; and wherein the signal pattern circuit further comprises a high frequency signal production circuit that generates a high frequency signal, and a switch coupled between the high frequency signal production circuit and the transformer so that the switch transmits the high frequency signal to the transformer when the switch is closed and suspends the transmission of the high frequency signal to the transformer when the switch is open whereby the signal pattern of the dimming level information signal comprises a series of high frequency pulses associated with the desired ballast dimming level.