7-14
Protection circuit: Over-voltage protection: The rising of output voltage can result in the increase of D201,
D203, D206 and D209 commute output voltage, and When OVP (PIN 2 of IC201) reaches the 2.0V threshold, PIN
1 (CTIMR) of IC201 charges the capacitor with a 3.0uA current. When CTIMR voltage reaches 3.0V, the IC201
shuts down (latch). Open-lamp protection: when the CCFL is suddenly removed or gets damaged/open during
operation, the lamp current is lost and thus FB (PIN 9 of IC201) drops. This causes CMP (PIN 10 of IC201) to
rise and when it reaches the 2.75V threshold, the IC201 shuts down (latch); additionally when SST (PIN 4 of
IC201) reaches a threshold about 1V below the VDDA (PIN 5 of IC201) voltage. For a nominal VDDA of 5.0V, the
threshold is 4.0V. then IC201 shuts down (latch) as well.
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