CXLE8467XH is a constant current driver chip designed specifically for isolated LED lighting. It adopts a flyback topology and supports a globally applicable input voltage of 85Vac~265Vac. The chip integrates 600V/650V high-voltage power MOSFETs and innovatively uses high-voltage JFET power supply and gate demagnetization detection technology, without the need for external VCC capacitors and starting resistors, greatly simplifying peripheral circuits, reducing system costs and volume, and improving overall reliability.
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[ CXLE8467XH ]"
In the trend of LED lighting towards high power and high reliability, a high-performance isolated driver chip is crucial for the overall performance of the system. JTM-IC has launchedCXLE8467XHThe high-precision flyback LED constant current driver chip, with its highly integrated design, full voltage input, multiple protection mechanisms, and excellent heat dissipation performance brought by DIP7 packaging, has become an ideal core solution for medium to high power LED lighting applications. This article will systematically analyze the technical architecture, performance advantages, and design points of CXLE8467XH, helping engineers build more stable and efficient lighting systems.
1、 Chip Overview: Empowering High Power Isolated Lighting
CXLE8467XH is a constant current driver chip designed specifically for isolated LED lighting. It adopts a flyback topology and supports a globally applicable input voltage of 85Vac~265Vac. The chip integrates 600V/650V high-voltage power MOSFETs and innovatively uses high-voltage JFET power supply and gate demagnetization detection technology, without the need for external VCC capacitors and starting resistors, greatly simplifying peripheral circuits, reducing system costs and volume, and improving overall reliability.
2、 Core highlights: high integration, high precision, and high reliability
2.1. Minimalist peripheral designNo need for VCC capacitors, starting resistors, and auxiliary winding power supply, significantly reducing the number of BOM components.
2.2. Accurate current output：± 5% LED output current accuracy ensures uniform lighting brightness and long-term operational stability.
2.3. Comprehensive protection mechanismBuilt in LED short circuit/open circuit protection, chip power supply undervoltage protection, overheating regulation function, strong self-protection ability of the system.
2.4. EN Enable ControlSupport pin control for intelligent dimming or remote switch control.
2.5. Excellent heat dissipation packagingAdopting DIP7 packaging, the thermal resistance is as low as 80 ℃/W, with good heat dissipation performance, suitable for output power up to 24W.
3、 Typical application scenarios
CXLE8467XH is widely applicable to various types of medium to high power isolated LED lighting equipment, such as:
· LED bulb lights (especially high-power models)
· LED tube light, panel light
· Mining lamp, outdoor lighting power module
4、 Key electrical parameters and selection guidance
Under the standard test conditions of TA=25 ℃, the main performance parameters of CXLE8467XH are as follows:
| parameter | condition | minimum | typical value | maximum | unit |
|---|---|---|---|---|---|
| Input voltage range | AC input | eighty-five | – | two hundred and sixty-five | Vac |
| Output power (230V+ 15%) | DH/EH/FHC version | – | ≤15/18/24 | – | W |
| operating frequency | Normal Mode | – | 65~70 | – | kHz |
| Current detection threshold VCS-TH | Constant current control | three hundred and ninety | four hundred | four hundred and ten | mV |
| Power transistor on resistance RDD_ON | EH version, VGS=10V | – | three | – | Ω |
| Overheating control point TREG | Chip surface | – | one hundred and forty | – | ℃ |
| boxed type | – | DIP7 | – | – | – |
The chip offers four versions: DH, EH, FH, and FHC, corresponding to different power levels and on resistance. Users can flexibly choose according to their output power requirements.
5、 Analysis of Deep Working Principle
5.1. Startup and power supply mechanism
After power on, the internal high-voltage JFET directly takes power from the HV pin to charge the internal VCC capacitor. After the voltage reaches the turn-on threshold, the control circuit starts. During operation, the JFET is continuously powered without the need for auxiliary windings, and the system structure is extremely simple.
5.2. Constant current control and current setting
The chip operates in inductor current discontinuous mode (DCM), detecting the peak current of the transformer's primary side through the CS pin and comparing it with the internal 400mV threshold to achieve cycle by cycle control.
The formula for calculating the peak current of the primary side is:
The output current of LED is determined by the transformer turns ratio:
Among them; RCS Flexible design for external sampling resistors.
5.3. Working frequency and system stability
The default frequency of the system is 65kHz; 70kHz。 The chip has built-in frequency limitation and demagnetization detection to ensure that the transformer operates within a safe range and avoid magnetic core saturation.
6、 Detailed explanation of all-round protection function
· LED open circuit protectionTrigger OVP and latch when open circuit, automatically reset and restart after 10ms.
· LED short circuit protectionWhen short circuited, the chip enters low-frequency mode (about 3.3kHz) with extremely low power consumption.
· Overheating regulationWhen the junction temperature exceeds 140 ℃, gradually reduce the output current to achieve temperature closed-loop control.
· Adjustable Overvoltage Protection (OVP)Set the protection voltage through the ROVP external resistor using the following formula:
Among them; TOVP Calculated from transformer parameters and preset OVP voltage.
· EN Control ReuseThe ROVP pin also has an enabling function, with voltage>0.3V turning on and<0.1V turning off the output, facilitating system integration.
7、 PCB Layout and Heat Dissipation Design Guide
A good layout is the key to ensuring system stability, low EMI, and good heat dissipation:
· Ground wire designThe ground wire of the current sampling resistor should be short and thick, and connected to the input capacitor ground at a single point with the chip ground.
· Minimize power loopReduce the loop area of the transformer's primary side power transistor absorption circuit and secondary side diode output capacitor.
· Heat dissipation enhancementThe DRAIN pin should be connected to the heat dissipation area through a large area of auxiliary copper, fully utilizing the heat dissipation advantages of DIP7 packaging.
· NC pin processingKeep suspended and ensure safe creepage distance.
· ROVP routingStay away from high-voltage switch nodes to avoid noise interference.
8、 Product advantages and selection comparison
CXLE8467XH is positioned as a medium to high power isolated driver in the JTM-IC product line, complementing other products in the same series
· Compare CXLE8434XH (SOP7,≤ 12W)CXLE8467XH has higher power and better heat dissipation, making it suitable for larger lighting fixtures.
· Compare CXLE83183B/CXLE83184CR (non isolated buck PFC)Suitable for scenarios with isolation safety requirements.
· cost-effectiveIntegrated power supply and protection, minimalist peripheral design, and low overall system cost.
9、 Extended application and technical support
JTM-IC not only provides high-performance chips, but also comes with a complete technical support system:
· Provide reference designs, transformer calculation tools, and PCB layout guidelines.
· Suitable for integrated solutions of intelligent lighting and dimming systems.
· For more models and in-depth application information, please visit the official website;jtm-ic.com obtain.
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10、 Conclusion
CXLE8467XH provides a reliable and efficient solution for isolated driving of medium to high power LEDs with its high integration, high precision, high power, and full protection characteristics. JTM-IC has always been committed to innovation in power management technology, providing customers with full support from chips to systems. If you need to obtain data manuals, sample applications, or technical support, please visit our official website;jtm-ic.comJoin hands with us to advance lighting technology towards a smarter and more energy-efficient future.
