ViewSonic VA903b-3 VS11372 Service Manual page 25

AC output.
The output stage consists of a tuning capacitor, transformer, and push-pull MOSFET pair to boost AC output up to
hundreds of voltage peak to peak.
And one resister is serial to lamp for output voltage feedback.
There are two signals which control the inverter come from system to turn on the inverter and control brightness.
Logic "low" level which send to U901 is turn on the inverter.
BL-ADJ signal control brightness by DC level which was integral from PWM signal.
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