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.
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
The LX1692 is a third-generation Direct Drive CCFL (Cold Cathode Fluorescent Lamp) controller. Designed for resonant full bridge inverter topologies, it integrates several safety features to protect against common lamp and circuit failures. Primary Protection Functions
The LX1692 includes an internal "Striking Block" and protection logic that monitors specific fault conditions:
Open Lamp Detection: Triggers if a lamp fails to strike or is disconnected.
Short Circuit Protection: Protects the inverter if a short occurs across the lamp terminals.
High Voltage Arcing: Detects and shuts down the controller in the event of arcing on the transformer secondary side.
Over-Voltage Protection: Limits the transformer secondary voltage to prevent breakdown. Protection Implementation & Timing
Protection on the LX1692 is typically managed through the following mechanisms:
Programmable Time-Out Protection: Users can set a specific duration for the striking period; if the lamp does not ignite within this window, the controller enters a protection shutdown state.
OVSNS & ISNS Pins: These pins (Over-Voltage Sense and Current Sense) are critical for monitoring fault thresholds. For example, the OVSNS pin uses zero-crossing and peak comparators to identify voltage irregularities.
LDO Filtering: The controller includes an integrated 4V LDO to power internal circuitry. A specific output pin must be connected to an external capacitor to stabilize this regulator, ensuring reliable operation of the protection logic. Troubleshooting: "Removing" Protection
In repair scenarios where the protection circuit prevents an inverter from turning on (often due to aging lamps), technicians sometimes "disable" the protection for diagnostic purposes. While specific pin-outs for disabling the LX1692 vary by application, common methods for similar controllers include grounding specific sense pins or using resistors to bypass fault signals. Note: Bypassing protection features can lead to transformer failure or fire hazards and should only be done for testing.
For detailed pin mapping, you can refer to the LX1692 Datasheet at Alldatasheet or Scribd. lx1692 PDF | PDF | Electronic Circuits | Capacitor - Scribd
The LX1692 protection pin is a critical component of the Microsemi LX1692, a third-generation Direct Drive CCFL (Cold Cathode Fluorescent Lamp) controller. This IC is designed to drive backlight lamps in LCD TVs and monitors using a resonant full-bridge inverter topology, which maximizes efficiency and lamp life. Overview of LX1692 Protection Features
The LX1692 integrates several safety mechanisms to prevent hardware damage from common backlight faults:
Open Lamp Protection: Detects if a lamp is disconnected or broken.
Short Circuit Protection: Shuts down the IC if a short to ground is detected, typically through an impedance of less than lx1692 protection pin
Arc Protection: Protects against electrical arcing within the high-voltage transformer or lamp connectors.
Programmable Time-Out Protection: Allows engineers to set a specific duration for "striking" (igniting) the lamp before a fault is triggered. Function of the Protection Pin
While "protection pin" is a general term used by repair technicians, the LX1692 datasheet specifically refers to several pins involved in the protection logic:
C_TO (Time-Out Capacitor Pin): This pin is used to program the strike time-out function. A capacitor connected here determines how long the controller will attempt to ignite the lamp before concluding there is a fault and entering a latched shutdown.
ISNS (Current Sense Pin): This is the primary monitoring point. During normal operation, the IC expects current levels to remain within a specific range (typically ). If the voltage at this input falls below
for more than 256 clock counts, the fault latch is set, and the device shuts down.
BRITE_D (Digital Dimming Input): A minimum voltage on this pin is required to prevent a "fault stop" during operation. Troubleshooting and Disabling Protection
In the television repair community, technicians often identify a specific pin to bypass or "disable" the protection circuit for diagnostic purposes. This allows them to see if the backlight briefly illuminates, helping to confirm if the issue is a faulty lamp, a damaged transformer, or the IC itself. lx1692 PDF | PDF | Electronic Circuits | Capacitor - Scribd
The LX1692 is a Cold Cathode Fluorescent Lamp (CCFL) controller typically used in LCD monitors and TVs. While it doesn't have a single pin explicitly labeled "Protection," its safety and fault functions are managed through several specific pins that monitor system health. Key Pins Involved in Protection
OVNS (Open Voltage Sense): This pin is critical for Open-Lamp Voltage Protection. It monitors the transformer's secondary voltage through a resistor divider to prevent it from exceeding safe limits during striking or if a lamp fails.
ISNS (Current Sense): Used for Short-Lamp and Arc Protection. It monitors the lamp current; if the signal exceeds approximately 0.7V, the IC confirms the lamp has "struck" (ignited) and moves into a standard running state.
CC_TO (Time-Out Capacitor): This pin allows for Programmable Time-Out Protection. By connecting an external capacitor, you can set the maximum "strike interval" duration. If the lamp fails to ignite within this time, the IC shuts down the outputs to prevent component damage.
ENABLE: While primarily for power management, this pin acts as a master override. If logic low, it disconnects internal power and disables all functions. Common Fault Protections The LX1692 architecture is designed to handle:
Open Lamp: Detected via the OVNS and ISNS pins if current doesn't flow after striking.
Broken/Short Lamp: Detected if the current feedback at ISNS is outside normal operating parameters.
Arc Protection: Triggers if voltage/current fluctuations indicate electrical arcing in the high-voltage lines. Are you troubleshooting a backlight shutdown issue, or lx1692 PDF | PDF | Electronic Circuits | Capacitor - Scribd
The LX1692 is a Direct Drive CCFL (Cold Cathode Fluorescent Lamp) controller, typically manufactured by Microsemi (now part of Microchip Technology). It is designed for resonant full-bridge inverter topologies used in LCD TVs and monitors.
The "protection pin" functionality in the LX1692 is distributed across several pins that monitor fault conditions to protect the inverter and transformer. Key Protection Pins and Functions
The LX1692 manages safety through integrated features that detect open-lamp, broken-lamp, and short-circuit conditions.
CT_OSC / C_TO (Programmable Time-Out): This pin is used to connect an external capacitor to program the protection time-out interval. During the "strike" phase (when the lamp is starting), if the lamp fails to ignite within the programmed time, the controller shuts down to prevent transformer damage.
ISNS (Current Sense): This pin continuously monitors lamp current levels.
Short-Circuit Protection: In RUN mode, if the current level at ISNS drops below 0.3V for 256 consecutive clock counts, a fault latch is set, and the IC shuts down.
Fault Thresholds: 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.
VIN_SNS (Input Voltage Sense): This pin uses an external resistor and capacitor to monitor the bridge power supply. It provides rapid response to line voltage transients and prevents transformer saturation by adjusting the timing ramp for open-lamp voltage regulation.
ENABLE: 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 <0.3Vis less than 0.3 cap V 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.
For detailed electrical specifications and pinout diagrams, you can refer to the LX1692 Datasheet at Alldatasheet or Datasheet.HK.
Are you trying to bypass the protection for troubleshooting?
Provide either:
If you provide the datasheet or exact part variant, I will produce a precise pin-level summary, recommended pull-up value, wiring diagrams, and test procedures. The Go to product viewer dialog for this item
For the LX1692 CCFL controller IC, the specific pin used for protection timing and fault management is typically the TIMR (Timer) pin. Function of the Protection Pin
The LX1692 includes safety features to protect against fault conditions such as open lamp, broken lamp, and short-circuit faults. The protection mechanism operates as follows:
Programmable Time-Out: The LX1692 datasheet specifies a "Programmable Time Out Protection". This is controlled by an external capacitor connected to the timer pin.
Fault Triggering: When a fault (like an open lamp) is detected, the IC begins charging the capacitor on the timer pin. If the voltage reaches a specific threshold before the fault is cleared, the IC shuts down the inverter to prevent damage to the transformers or other components. Disabling or Bypassing Protection
In repair scenarios where a technician needs to troubleshoot a "backlight on then off" issue, the protection is often bypassed to keep the lamps lit for testing. For many similar CCFL controllers, this is done by: Connecting a resistor (typically between
) between the timer pin and ground to keep the voltage below the shutdown threshold.
Directly grounding the pin, though the specific method depends on whether the IC triggers on high or low voltage. lx1692 PDF | PDF | Electronic Circuits | Capacitor - Scribd
The LX1692 is a third-generation Cold Cathode Fluorescent Lamp (CCFL) controller often found in LCD TV backlight inverters. The "protection pin" is a critical diagnostic point used to sense fault conditions and trigger a shutdown to prevent damage to the inverter or transformer. 🛠️ Identifying the Protection Pin On the Microsemi LX1692
, the protection mechanism is typically associated with Pin 14 (often labeled as OVP or PROT in repair guides). What it monitors: Open Lamp: Detects if a bulb is missing or broken.
Short Circuit: Prevents high current from damaging the MOSFETs.
Over-Voltage: Limits the transformer's secondary voltage to avoid arcing.
Arc Protection: Senses electrical arcing in the high-voltage section. 🔍 How the Protection Works
The IC monitors voltage levels on specific sensing pins (like OVSNS for over-voltage and ISNS for current). If these values exceed preset thresholds, the internal logic triggers the protection pin to stop the gate drivers. Common Shutdown Causes:
Aging Lamps: Old CCFL bulbs require higher voltage to "strike," which can trip the over-voltage protection.
Leaky Capacitors: Small blue high-voltage capacitors on the output often fail and leak current to ground.
Transformer Failure: Shorted windings in the inverter transformer will trigger immediate shutdown. ⚡ Bypassing for Troubleshooting
Technicians sometimes "disable" the protection pin to identify which specific lamp or transformer is failing. Warning: This is for diagnostic purposes only and can be dangerous if left permanently. The Method: For many
variants, connecting a resistor (typically 4.7kΩ to 10kΩ) from the protection pin to ground can sometimes keep the IC running.
Visual Clues: If you bypass protection and see one part of the screen is darker, or hear a "hissing" sound, you have found the faulty lamp or arcing transformer. 💡 Key Technical Specs Operating Topology: Resonant Full Bridge. Package Type: 20-Pin TSSOP or SOIC. Dimming: Supports both Analog and Digital (PWM) dimming.
Integrated LDO: Features a 4V internal regulator for control logic. If you're troubleshooting a specific device, let me know: Is the screen flashing and then going black? Do you have a multimeter to check the voltage on the pins? What is the exact TV model or board number? LX1692 Datasheet(PDF) - Microsemi Corporation
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
The LX1692 is a highly integrated Direct Drive CCFL (Cold Cathode Fluorescent Lamp) controller. In the context of LCD and LED television repair, the "protection pin" refers to a specific input on the integrated circuit (IC) that monitors system parameters to prevent damage from faults like over-voltage or open-lamp conditions. The Role of the Protection Pin
The primary purpose of the protection pin is safety. It acts as a sensor for the IC’s internal protection logic. If the voltage or current feedback deviates from safe operating limits, the IC triggers a shutdown to protect the backlight inverter and the panel.
Detection of Faults: It monitors for issues such as aged lamps, broken CCFL tubes, or faulty high-voltage transformers. If you want a datasheet-derived, exact description Provide
System Shutdown: Once a fault is detected, the IC stops the switching pulses to the power stage, causing the backlight to turn off—often seen as a "one-second" or "two-second" flash of the screen followed by darkness. Bypassing for Troubleshooting
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.
Pin Identification: On the LX1692, protection is typically managed via specific pins like Pin 4 (COMP) or Pin 14 (TIMER), depending on the specific board revision and implementation.
The Bypass Method: Disabling the protection usually involves modifying the voltage at the protection pin. For many CCFL controllers, this is achieved by connecting a resistor (commonly between
) from the timer pin to ground, or by applying a stable reference voltage to the comparator pin.
Risk Warning: Bypassing protection is a diagnostic step only. Operating a TV with the protection disabled can lead to overheating, fire hazards, or permanent damage to the transformer and panel. Summary of Implementation
The LX1692 uses its protection circuitry to balance high-efficiency performance with system longevity. While disabling this feature can be a powerful tool for repair professionals to "force" the backlight on for testing, the ultimate goal should always be to find the root cause—such as a failing lamp—rather than permanently leaving the protection pin inactive. Backlight Protect
Understanding the LX1692 Protection Pin: A Comprehensive Guide
The LX1692 is a highly integrated, high-performance power management IC (PMIC) designed for a wide range of applications, including industrial, automotive, and consumer electronics. One of its key features is the LX1692 protection pin, which plays a crucial role in ensuring the reliability and safety of the system. In this article, we will provide an in-depth exploration of the LX1692 protection pin, its functions, and its significance in system design.
Introduction to the LX1692 PMIC
The LX1692 PMIC is a highly versatile and efficient power management solution that offers a range of features, including voltage regulation, power switching, and protection functions. It is designed to operate in a wide range of applications, from low-power IoT devices to high-power industrial systems. The LX1692 PMIC is built with a high-performance architecture that provides high efficiency, low power consumption, and high reliability.
Overview of the LX1692 Protection Pin
The LX1692 protection pin is a critical feature of the PMIC that provides an additional layer of protection against various types of faults and abnormal operating conditions. The protection pin is designed to detect and respond to faults such as overvoltage, undervoltage, overcurrent, and short circuits. When a fault is detected, the protection pin can trigger a shutdown or alert the system to take corrective action.
Functions of the LX1692 Protection Pin
The LX1692 protection pin has several key functions that make it an essential component of the PMIC:
Significance of the LX1692 Protection Pin in System Design
The LX1692 protection pin plays a crucial role in ensuring the reliability and safety of the system. Here are some reasons why:
Design Considerations for the LX1692 Protection Pin
When designing a system with the LX1692 PMIC, there are several design considerations to keep in mind:
Conclusion
The LX1692 protection pin is a critical feature of the PMIC that provides an additional layer of protection against faults and abnormal operating conditions. Its functions, including overvoltage, undervoltage, overcurrent, and short circuit protection, make it an essential component of the PMIC. By understanding the LX1692 protection pin and its significance in system design, designers can create more reliable, safe, and efficient systems. Whether you're designing industrial, automotive, or consumer electronics, the LX1692 protection pin is an essential feature to consider.
Specifications and Technical Details
For designers and engineers looking for more technical details, here are some specifications and technical details of the LX1692 protection pin:
Additional Resources
For more information on the LX1692 PMIC and its protection pin, we recommend the following resources:
By providing a comprehensive understanding of the LX1692 protection pin, we hope to help designers and engineers create more reliable, safe, and efficient systems. If you have any questions or need further assistance, please don't hesitate to contact us.
Here is the technical breakdown of the protection functionality for the LX1692:
In the world of power management and integrated circuits (ICs), the smallest components often have the most critical jobs. One such component, the LX1692, is a highly specialized controller used primarily in CCFL (Cold Cathode Fluorescent Lamp) backlight inverters. While the chip itself manages power conversion for LCD screens, one specific pin on this chip has become a legendary point of failure and repair among electronics technicians: The LX1692 Protection Pin.
If you have ever dealt with an LCD monitor that turns on for one second and then shuts off, or a laptop screen that stays black despite the computer running, you have likely met the LX1692 protection circuit in action. This article dives deep into the purpose, voltage behavior, common failure modes, and diagnostic techniques for the LX1692 protection pin.