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Lx1692 Protection Pin

Monitors localized high-voltage tracking that could damage the underlying PCB board or high-voltage transformers.

Monitors lamp current. If the signal is below a specific threshold (e.g., 0.3 cap V sub p k end-sub during strike), it may trigger open-lamp protection. OVSNS (Over Voltage Sense):

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Measure the secondary windings of the step-up transformers. If the resistance values vary by more than 3% to 5% between transformers, it often indicates a shorted winding, which will continuously trip the IC.

Shuts down the IC if a short to ground is detected, typically through an impedance of less than : This pin monitors the return current flowing

Here is the interesting engineering nuance:

The screen goes completely dark, but the power LED stays green, and audio can still be heard. the IC flags an open-lamp condition.

: This pin monitors the return current flowing through the CCFL tubes. If a single voltage cycle at the ISNS pin surpasses 0.7V peak , the IC transitions from its strike mode into its normal run state. If the voltage drops below its baseline run threshold, the IC flags an open-lamp condition.

4. Technical Comparison: LX1692 vs. Alternative CCFL/LED Topologies

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This ensures that the IC and the system operate within a valid voltage range. If the voltage falls below a certain threshold, the UVP circuit can shut down the IC or prevent it from operating to protect against undervoltage conditions.