CXLE82137AS is an LED constant current controller dedicated to non-isolated Buck topology, suitable for wide voltage input from 85Vac to 265Vac. Its core design concept is "flexible adjustment, comprehensive protection and Concise System".
The chip works in the critical continuous mode of inductor current without the need of auxiliary winding for demagnetization detection. The internal integration of high-voltage JFETs power supply lines eliminates the need for external VCC capacitors and start-up resistance, greatly reduces the number of peripheral components, reduces system costs and fabric swatch space, and is especially suitable for high-power LED lamp applications sensitive to cost and volume.
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[ CXLE82137AS ]"
CXLE82137AS dial adjustment current step-down LED controller-JTM-IC high flexibility four-gear OVP and soft start solution
Under the background that LED lighting systems are increasingly pursuing intelligence, adjustability and high reliability, a drive controller with flexible current regulation, multiple protection and easy integration has become an urgent demand in the market. JTM-IC (jtm-ic.com) CXLE82137AS is a non-isolated step-down LED constant current controller designed for DIP switch current regulation. It not only supports wide-range current regulation, but also has four-gear optional overvoltage protection (OVP) voltage, enable and soft start functions, providing high integration, high reliability, and high power LED lamp, an integrated solution that is easy to debug.
I. CXLE82137AS product overview and positioning
CXLE82137AS is an LED constant current controller dedicated to non-isolated Buck topology, suitable for wide voltage input from 85Vac to 265Vac. Its core design concept isFlexible adjustment, comprehensive protection and simple system".
The chip works in the critical continuous mode of inductor current without the need of auxiliary winding for demagnetization detection. The internal integration of high-voltage JFETs power supply lines eliminates the need for external VCC capacitors and start-up resistance, greatly reduces the number of peripheral components, reduces system costs and fabric swatch space, and is especially suitable for high-power LED lamp applications sensitive to cost and volume.
II. Core functions and technical highlights
2.1. DIP switch adjustable current (40%-100% adjustable)
The DIM pin of CXLE82137AS supports selecting different ground resistance through external dip switch to realize linear adjustment of output current from 40% to 100%.The biggest highlight is that when the output current is adjusted, the OVP protection point is not affected., system security is always guaranteed to avoid overvoltage risk caused by dimming.
2.2. Four-gear optional OVP voltage (135V/225V/320V/Unlimited)
Through the external resistor of the ROVP pin, users can flexibly choose the four-speed open circuit protection voltage: 135V, 225V, 320V or completely turn off the OVP function. This design enables the same chip to adapt to LED lighting chain with different output voltage levels, improving the versatility of the scheme.
2.3. DIM pin multi-function multiplexing (enable soft start)
· Enable function: When the DIM voltage is lower than 100mV, the chip stops working, which can easily realize intelligent control such as switch color mixing and human body induction.
· Soft start function: parallel capacitors in DIM pin pair can achieve slow rise of CS current reference, so as to smoothly start and reduce the startup impact current. It is especially suitable for systems with front-stage and PFCs to reduce component stress.
2.4. High precision constant current and comprehensive protection
·The output current accuracy is as high as ± 5%, with excellent line voltage and load adjustment rate.
·Integrated multiple protection: LED open circuit/short circuit protection, chip VDD undervoltage protection, cycle-By-Cycle current limiting, overheating regulation, etc., with strong system robustness.
III. Internal structure and working principle
CXLE82137AS internal integration of high-voltage power supply module, VDD undervoltage locking, OVP control logic, overheating regulation, control core, drive circuit, demagnetization detection, leading edge blanking and accurate current sampling units.
Startup Process: the input voltage supplies power to the internal JFETs through the HV pin to establish VDD. After the voltage reaches the open threshold, the control circuit starts to work. During chip operation, work current is continuously provided by internal JFETs without external auxiliary power supply.
Constant current control mechanism: The chip samples the CS pin voltage (from the external sampling resistor) cycle by cycle. Compared with the internal adjustable threshold voltage, it controls the switch of the external MOSFET to realize the peak inductor current control.
The average output current is approximately:
VCS_TH is controlled by the DIM pin voltage to adjust the current.
3.2. Internal structure
IV. Key design guidelines and parameter calculation
4.1. Selection of dial resistance and current setting
The DIM pin has an internal pull-up current of 20 μA. By adjusting the DIM resistance to ground RDIM, the DIM voltage can be changed, and then the CS threshold can be linearly adjusted to realize current programming. The current regulation range covers the rated value of 40% to 100%.
4.2. OVP gear resistance configuration
The ROVP pin has a pull-up current of 40/a. By connecting different resistance values to the ground, four-speed OVP voltage can be set:
|
ROVP ground voltage |
<0.2V |
0.2-0.6V |
0.6-1.8V |
> 1.8V |
|---|---|---|---|---|
|
OVP voltage |
135V |
225V |
320V |
No OVP |
4.3. Design of energy storage inductance
The system works in critical mode, and the inductance value calculation formula is as follows:
Where IPK = 2×iled.
To ensure the stable operation of the system in critical mode, ensure that the Power Tube off-time TOFF meets:
The system may enter intermittent or continuous mode beyond this range, affecting the constant current accuracy.
V. PCB layout and heat dissipation suggestions
Good layout is the key to ensuring performance and EMI:
5.1. CS sampling loop: The Power ground wire of the sampling resistor should be short and thick, and be independently routed to the input capacitor touchdown.
5.2. High voltage isolation: the HV pin should be far away from low voltage signal pins such as CS and DIM.
5.3. Power loop minimization: reduce the Loop area of power inductor-MOSFETs-input capacitors and power inductor-flyback diode-output capacitors to reduce EMI radiation.
5.4. Heat dissipation treatment: appropriately expand the copper laying area of GND pin, and use the bare pad at the bottom of the chip (if applicable) to enhance heat dissipation.
6. Typical application scenarios
With its flexible current regulation, optional OVP gear and comprehensive protection functions, CXLE82137AS is very suitable for the following applications:
·High-power LED bulb, mining lamp, high ceiling lighting
·Commercial Lighting requiring multi-speed dimming and high safety requirements
·High-performance LED driving power supply combined with front-stage PFCs
·Intelligent dimming, color mixing or induction control integrated lamp system
VII. Packaging and ordering information
CXLE82137AS adopts standard SOP-8 package with compact package size, which is convenient for automatic patch production. The order model is CXLE82137AS, and the package is in the form of Reel, each plate has 4000 pieces, which is suitable for large-scale production and supply.
VIII,Electrical Performance
IX,Related productsmore...
10. Conclusion
CXLE82137AS provides unprecedented flexibility and reliability for LED lighting system designers with its unique dial-up current adjustment architecture, four-gear optional OVP protection, and highly integrated design. Its characteristic of "regulating flow without regulating voltage" fundamentally improves the security of the system in dimming scenarios, the abundant protection mechanisms ensure the stable operation of end products in various harsh environments.
JTM-IC has always been committed to providing high-performance, highly integrated and highly reliable power management solutions for the global lighting industry through technological innovation. To obtain the complete data sheet, application notes, or application samples of CXLE82137AS, please visit our official website:jtm-ic.comTo obtain more technical resources and support.
This article was written by the JTM-IC technical team. Please specify the source for reprinting.jtm-ic.com, welcome industry exchanges and technical consultation.
