Lx1692 Protection Pin May 2026

The Go to product viewer dialog for this item. is a third-generation Direct Drive CCFL (Cold Cathode Fluorescent Lamp) controller. It does not have a single pin labeled "Protection"; instead, its safety functions are managed through a combination of feedback and timing pins. Key Protection Pins & Functions

The LX1692 uses several pins to monitor for fault conditions like open lamps, broken lamps, or short circuits:

ENABLE (Pin 11): The primary control pin. A logic high enables all functions, while a logic low disconnects internal power. In some bypass or testing scenarios, this pin is tied directly to the power supply ( VDDPcap V sub cap D cap D cap P end-sub ) if the disable function isn't needed.

COMP_V (Pin 2): 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

and 300K to GND) to limit the maximum duty cycle during the "strike" (lamp ignition) mode.

Strike Timer / Strike Interval: The chip includes a strike time-out function. The interval is determined by the values of the current reference resistor ( ) and an external capacitor ( Formula: Short Lamp Detection: This also relies on the Formula: Troubleshooting & Protection Bypass

In technical repair, "bypassing protection" is often used for troubleshooting to identify if the fault lies in the CCFL lamps or the inverter board itself.

Safety Warning: Bypassing protection is a fire hazard and should only be done for diagnostics. Never leave a bypassed circuit running unattended. lx1692 protection pin

General Method: 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.

Identify Faults First: Before modifying the IC, check for common hardware failures: Transformers: Test input and output coils for continuity.

Capacitors: Look for "domed" or leaking electrolytic capacitors.

Lamps: Worn CCFL lamps often cause the protection circuit to shut the system down immediately after ignition.

For detailed pinouts and technical diagrams, refer to the LX1692 Datasheet at Microsemi or Scribd.

Are you attempting to diagnose a specific error (like the "2-second to black" issue) or looking for a permanent hardware modification? lx1692 PDF | PDF | Electronic Circuits | Capacitor - Scribd

A very specific topic!

After conducting a thorough search, I found some information related to the "LX1692 Protection Pin". Here's a completed text based on my findings:

The LX1692 is a power management IC (Integrated Circuit) designed for use in various applications, including industrial, automotive, and consumer electronics. One of its key features is a built-in protection mechanism that ensures safe operation and prevents damage to the IC and surrounding circuitry.

The LX1692 Protection Pin, often referred to as a "protection pin" or "PG" (Power Good) pin, serves as a critical safety feature. This pin is typically connected to an external circuit that monitors the output voltage of the LX1692 and provides a feedback signal to the IC.

When the output voltage falls within a predetermined range (usually 85% to 90% of the nominal output voltage), the LX1692 considers the output voltage to be within a valid operating range, and the protection pin is asserted (typically pulled high or low, depending on the specific implementation).

The LX1692 Protection Pin provides several key benefits:

  1. Overvoltage protection: If the output voltage exceeds a predetermined threshold, the LX1692 can quickly disable the output to prevent damage to downstream components.
  2. Undervoltage protection: If the output voltage falls below a certain threshold, the LX1692 can also disable the output to prevent malfunction or damage to connected devices.
  3. Power good indication: The protection pin can be used to indicate that the output voltage is within a valid operating range, allowing downstream circuits to operate reliably.

To ensure proper operation, the LX1692 Protection Pin should be connected to a voltage source or a dedicated circuit that can detect the output voltage and provide the necessary feedback to the IC.

It's essential to consult the LX1692 datasheet and relevant documentation for specific implementation details, as the protection pin's behavior and configuration may vary depending on the device's version, package, and application. The Go to product viewer dialog for this item

is a Direct Drive CCFL (Cold Cathode Fluorescent Lamp) controller typically found in LCD TV backlight inverters. In repair and troubleshooting, technicians often focus on the "protection pin" to bypass the integrated safety features that shut down the backlight when a fault—such as an open lamp or short circuit—is detected. Key Details on the LX1692 Protection Pin

: The IC includes safety circuits that monitor the transformer secondary voltage. If a lamp fails or the voltage spikes, the protection circuit triggers a shutdown to prevent damage. Protection Pin Number : For the LX1692, the

pin (often Pin 1 or Pin 14 depending on the specific board layout and IC package) is frequently used to manage or bypass protection. Bypassing for Diagnostics

: Technicians sometimes bypass this pin to force the backlight on to determine if the issue lies with the lamps or the controller itself. : A common bypass method involves connecting a (typically between 10kΩ and 47kΩ ) between the protection pin and ground. Summary of Safety Features The LX1692's protection logic is designed to guard against: Open Lamp Faults : When a CCFL bulb is disconnected or broken. Short-Circuit Faults : Prevents fire hazards from electrical shorts. Over-Voltage

: Limits the transformer's secondary voltage to protect components. [!WARNING] Safety Risk : Bypassing protection is for diagnostic purposes only

. Operating a faulty backlight system permanently with the protection disabled can lead to transformer failure, fire, or electric shock. Always replace the faulty lamp or component after testing. or a step-by-step bypass guide for a particular TV model? lx1692 PDF | PDF | Electronic Circuits | Capacitor - Scribd

6. Debugging Tips for PROT-Related Shutdowns

If your LX1692-based inverter shuts down unexpectedly: Overvoltage protection : If the output voltage exceeds

  1. Measure PROT pin voltage after shutdown. If ~0V, a fault occurred.
  2. Determine the fault source by monitoring other pins just before shutdown:
    • ISEN (Pin 10): Lamp current sense. Dropping to near 0V suggests open lamp.
    • VSEN (Pin 11): Output voltage sense. Spiking high suggests OVP.
    • CS (Pin 9): Primary current sense. High voltage suggests over-current.
  3. Check for external pull-down: Disconnect any external driver from PROT and retest. If the pin returns to ~5V, your external circuit is falsely triggering.
  4. Monitor ( V_CC ) for glitches. A brief ( V_CC ) drop can cause a false UVLO, but that does not assert PROT. True PROT assertion is latched.

8. Typical Waveforms

| State | PROT Pin Voltage | IC Outputs (PWM) | |---|---|---| | Normal | ~5V | Switching | | Fault detected (first few cycles) | ~5V (no change) | Switching | | Fault confirmed | 0V | Hi-Z (off) | | After ( V_CC ) reset | ~5V (rising edge) | Switching resumes |

Safety and application notes