OV_SNS通过一个外部分压网络（典型分压比约为1000:1）监视冷阴极灯管两端的电压。芯片不仅用它来实现开路灯管电压的精准稳压调节，还用它在启辉（Strike）和正常点亮（Run）阶段中监控灯管开路故障。
Because the output voltage can exceed 1,000V RMS during the striking phase, a high-voltage capacitor network steps this voltage down to a safe level (typically under 2V–3V) for the sensing pin.
LX1692 是第三代直接驱动CCFL的控制器，由Microsemi Corporation（现隶属于Microchip）制造，Mitsumi公司也提供该芯片的相关数据手册，但在技术应用上以Microsemi为主导。该芯片最核心的设计逻辑是采用，利用该特性将电源拓扑从传统的推挽式（Push-Pull）进化为谐振式（Resonant）。这种优化带来了三大优势：它为CCFL灯管提供的近乎正弦波的电流能极大延长灯管寿命；得益于零电压开关（ZVS）软开关技术，系统效率得到显著提升；平稳光滑的开关波形大幅降低了电磁干扰（EMI）。
Technicians often "bypass" or "disable" this protection during the diagnostic phase to keep the backlight on long enough to identify which specific component is failing. lx1692 protection pin
While there are no direct equivalents for every LX1692 variant, alternative manufacturers and part numbers can sometimes be used.
If the voltage on the monitoring pins (such as the lamp current feedback loop) does not reach operational parameters before the external capacitor finishes charging to its internal threshold, the chip flags a persistent fault. It cuts the gate drive signals to the four external power MOSFETs, disabling the high-voltage output to prevent component meltdown.
The LX1692 includes several safety mechanisms to prevent transformer damage and ensure safe lamp operation: Open Lamp Voltage Protection: If the voltage on the monitoring pins (such
Degraded ceramic capacitors in the high-voltage voltage divider network can alter the division ratio. If a capacitor leaks or changes value, it may deliver an artificially high voltage to the PROT pin, causing false protection trips on a perfectly healthy inverter. Bypass and Diagnostic Techniques (For Bench Testing Only)
The most common causes of a false protection trip are:
The voltage loop compensation pin. This pin is used for transformer output voltage regulation. An external resistor divider is typically connected here (recommended: 100K to VDDAcap V sub cap D cap D cap A end-sub If a capacitor leaks or changes value, it
Often, one of the transformers has a slightly open secondary winding, triggering the protection, even if the primary side looks fine.
In a standard application diagram, Pin 5 does not connect directly to the high-voltage lamp output. Instead, it receives a scaled-down, rectified DC voltage from a feedback network.
: The chip deactivates over-voltage fault shutdowns until the voltage across the C_TO capacitor crosses 3.5V . This delay provides a user-defined window to ignite the lamps safely.
Sets internal bias currents and determines the strike time-out interval. Used for digital dimming and programmable burst frequency. Troubleshooting and Bypassing Protection