Koninklijke Philips Corporation N.V.

Sree Venkit

Yuhong Fang

Bruce Robeson Rhodes

George Grouev

Sanjaya Kumar Pradhan

Arun Ganesh

Ramakrishnan Venkatraman

Alejandro Lopez

Amr Ghazala

An electronic ballast and startup method including an electronic ballast operably connected to a lamp having a lamp filament, the electronic ballast having a timer () generating an inverter control signal () and a preheat control signal (); a converter () receiving AC power and generating DC power (); a self-oscillating inverter () receiving DC power () and being operable to provide lamp power () to the lamp, the self-oscillating inverter () being responsive to the inverter control signal (); and a filament preheater () receiving DC power () and being operable to provide filament power () to the lamp filament, the filament preheater () being responsive to the preheat control signal (). When AC power is initially applied, preheat control signal () directs the filament preheater () to provide filament power (), and inverter control signal () directs the self-oscillating inverter () not to provide lamp power ().

Electronic ballast and startup method

A striation correction circuitis arranged to apply a first striation correction current to the first fluorescent lamp Land a second striation correction current to the second fluorescent lamp L. A first voltage appearing across the first fluorescent tube Ldue to the first striation correction current is substantially similar in magnitude but has inverted polarity with respect to a second voltage across the second fluorescent tube Ldue to the second striation correction current. Detection of an end-of-life condition of a fluorescent lamp is facilitated.

Symmetric cancelling anti-striation circuit

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Naperville, IL, United States of America

Sree Venkit