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Electronic ballasts should be well designed to operate
fluorescent lamps at high frequency with long lifetime and
appropriate illumination. Among various ballast circuit
configurations, the series resonant inverter has been proved to
be of high efficiency and cost effective. The operation of the
lamp with a series resonant inverter can be described by three
circuit models, namely starting, steady-state, and open
circuit. Based on these models, the circuit parameters of the
resonant tank including the starting circuit can be pre-
estimated according to the electrical ratings of the specified
lamp. These parameters are verified by computer simulation with
Pspice model and then to be modified to obtain more accurate
results. Finally, a prototype circuit for a 36-Watt lamp is
built and tested. The starting circuit and protection circuit
at open circuit operation are also included.
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