Patent ID: 6160362
Filing Date: 2000-12-12
Classification: H05B,Y02B,Y10S

Abstract:
An electronic ballast for starting a high intensity discharge lamp having breakdown, non-thermionic glow and thermionic arc phases prior to entering a steady state operating mode, comprising:a resonant ignitor for applying a lamp voltage across the lamp;an exciter, responsive to a varying control signal, for exciting the resonant ignitor at a varying operating frequency; anda controller for producing the varying control signal based on the phase of the lamp;wherein prior to breakdown the controller adjusts the control signal so as to decrease the operating frequency so as to sweep toward a lamp voltage equal to a predetermined ignition voltage and wherein upon entering the glow phase the controller further adjusts the control signal so as to minimize the time duration within the glow phase and wherein upon entering the thermionic arc phase the controller further adjusts the control signal so as to increase lamp current.