CXLE8460 is a single-stage active power factor correction (APFC) control chip suitable for input voltages ranging from 90V to 277V. It adopts a fixed conduction time control mechanism, combined with a built-in THD optimization module, to achieve high power factor and low harmonic distortion performance with PF>0.9 and THD<15%. The chip operates in critical conduction mode (CrM), which not only effectively reduces switching losses and EMI interference, but also significantly improves the utilization efficiency of transformers.
-
[ CXLE8460 ]"
CXLE8460: Comprehensive Analysis of High Precision Primary Edge Feedback LED Constant Current Control Chip
In the field of LED lighting power supply design, efficient, stable, and high power factor driver chips are the key to ensuring the performance and lifespan of lighting fixtures. Launched by JTM-ICCXLE8460It is a high-precision primary feedback constant current control chip designed specifically for LED internal/external power supplies. This article will deeply analyze its technical characteristics, application circuits, design points, and protection mechanisms, helping engineers better understand and apply the chip, and improve the reliability and performance of power systems.
1、 Chip Overview and Core Advantages
CXLE8460 is a device suitable for a full range of input voltages from 90V to 277VSingle stage active power factor correction (APFC) Control chip. It adoptsFixed conduction time control mechanismCombined with the built-in THD optimization module, it has achievedPF > 0.9 THD < 15% High power factor and low harmonic distortion performance. The chip works inCritical conduction mode (CrM)Not only does it effectively reduce switch losses and EMI interference, but it also significantly improves the utilization efficiency of transformers.
This chip adoptsSOP-8 encapsulationWith high integration and simple peripheral components, it is suitable for isolated/non isolated Buck Boost topology structures, especially for high-performance LED lighting driver design.
2、 Main technical features
• Wide voltage inputSupports 90V~277V AC input and adapts to mainstream global power grid standards.
• High precision constant current output: Built in± 3% precision current benchmark ensures stable output current.
• Built in high voltage startStart time<500ms, rapid response.
• Multiple protection mechanismsIt has functions such as output open/short circuit protection, cycle by cycle current limiting, VCC undervoltage locking, and over temperature drop current.
• Low working current and high efficiencyThe static current is extremely low, and the overall energy efficiency of the system is excellent.
3、 Typical Application Circuits and Design Points
CXLE8460 supportsDouble winding Flyback (without auxiliary winding) andThree winding FlybackTwo typical topologies can be selected based on actual applications, either floating or solid structures.
Output current setting formula:
among which
• VREF =200mV (typical value)
• RCS =Current sampling resistor
• Np/Ns =Transformer primary to secondary turns ratio
Feedback network and OVP settings:
Implement output overvoltage protection (OVP) through the FB pin, with a threshold set at 1.5V. The recommended ratio of voltage divider resistors is as follows:
Reasonably setting RFBL and RFBH can accurately control the output voltage protection point.
4、 Detailed explanation of protection function
CXLE8460 is equipped with comprehensive protection mechanisms to ensure the safe operation of the system in various abnormal situations:
• Output open/short circuit protectionWhen an output abnormality is detected, the chip enters low-frequency mode and triggers protection logic.
• Cycle by cycle current limitingWhen the CS pin voltage exceeds 1V, immediately turn off the current cycle to prevent overcurrent damage.
• Overheating regulationWhen the junction temperature exceeds 150 ℃, the output current will be automatically reduced to control the temperature rise of the system.
• VCC undervoltage lockEnsure that the chip operates within a safe voltage range.
5、 PCB design suggestions
A good PCB layout is the key to ensuring system stability and EMI performance:
• VCC bypass capacitorIt should be placed close to the chip pins.
• Power ground of current sampling resistorIt should be short and connected directly to the chip GND.
• FB voltage divider resistorKeep close to the FB pin and away from noise sources.
• Power loop areaIt should be minimized to reduce radiation interference.
6. Conclusion
CXLE8460 is an ideal choice in the field of LED driver power supply due to its high precision, high PF, comprehensive protection functions, and simple peripheral design. This chip can provide stable, efficient, and reliable constant current drive solutions for indoor lighting, outdoor lighting fixtures, and high-performance industrial lighting systems.
For more technical information, sample application or design support, please visit the official website of Jiataimu:jtm-ic.comWe will provide you with professional product services and technical support.
