A universal line voltage dimming method and system, with a control circuit for an electronic ballast including an on-time converter (50) generating an on-time signal (54) in response to a sensed phase-controlled power signal (52), and a micro-processor (56) responsive to the on-time signal (54) and generating a dimming control signal (58). A lamp control method for an electronic ballast includes sensing phase-controlled power, determining on-time for the sensed phase-controlled power, and controlling lamp dimming in response to the on-time.