Patent ID: 7852017

Claim:
A lighting system ballast comprising: a light source driver stage configured to deliver power to one or more light emitting diodes with an adjustable drive current; a sensor having one or more input terminals to receive a phase modulated dimmer signal, wherein a phase delay of the phase modulated dimmer signal indicates a dimming level and the sensor is configured to detect the dimming level and to generate a dimmer output signal representing a dimming level indicated by the dimmer signal; and a controller coupled to the light source driver stage and the sensor, wherein the controller includes at least one input terminal to receive the dimmer output signal from the sensor and to generate a drive control signal to cause a drive current supplied to each light emitting diode to dim each light emitting diode in response to the dimmer signal, wherein the drive current is approximately constant for each dimming level throughout a cycle of the phase modulated dimmer signal.