Lx1692 - Protection Pin

The LX1692 includes several safety mechanisms to prevent transformer damage and ensure safe lamp operation: Open Lamp Voltage Protection:

This pin serves as a global control. If the logic is low, internal power is disconnected from the VDDP pin, effectively disabling all functions as a primary safety or power-saving measure. Summary of Fault Protections Protection Type Trigger Condition Resulting Action Open Lamp Secondary voltage exceeds limit without current flow. Controller enters shutdown or limits voltage. Short Circuit ISNS voltage for 256 clock counts. Fault latch is set; IC shuts down. Time-Out Strike interval exceeds time set by CTOcap C sub cap T cap O end-sub capacitor. IC stops trying to strike the lamp. lx1692 protection pin

For many backlight controllers, protection is bypassed by connecting a resistor (typically 10kΩ to 47kΩ ) between the timer/protection pin and ground to prevent the IC from "tripping" due to sensed faults. The LX1692 includes several safety mechanisms to prevent

It typically handles normal operating levels of ±0.5Vplus or minus 0.5 cap V to ±5.5Vplus or minus 5.5 cap V , but can tolerate transients up to ±11VPKplus or minus 11 cap V sub cap P cap K end-sub under fault conditions. Controller enters shutdown or limits voltage

The LX1692 monitors four key parameters. If any of these exceed safe thresholds, the IC will internally pull PROT low: