CXLE83176 is a high-precision LED constant current driver chip based on analog dimming control mode. It adopts PWM input dimming mode, and the dimming range covers 1% ~ 100%. There is no stroboscopic and noise in the whole process, and the dimming consistency is excellent. The chip is suitable for a wide input voltage range of 85VAC ~ 270VAC, with excellent linearity and load regulation, and constant current accuracy as high as ± 5%.
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[ CXLE83176 ]"
CXLE83176: high precision external MOS buck LED driver chip comprehensive analysis
In the design of intelligent lighting system, the dimming performance, system cost and reliability of LED driver chip have become the key considerations for engineers to select. As a high-precision non-isolated step-down LED constant current driver chip specially designed for stroboscopic and noise-free intelligent lighting, CXLE83176 adopts external MOS architecture, supports wide voltage input and PWM dimming, and is widely used in LED bulb lamps, ceiling lamps and other scenes. This article will systematically introduce the technical characteristics, working principle, design points and typical applications of the CXLE83176 to help developers give full play to their performance advantages.
1. Product Introduction
CXLE83176 is a high-precision LED constant current driver chip based on analog dimming control mode. It adopts PWM input dimming mode, and the dimming range covers 1% ~ 100%. There is no stroboscopic and noise in the whole process, and the dimming consistency is excellent. The chip is suitable for a wide input voltage range of 85VAC ~ 270VAC, with excellent linearity and load regulation, and constant current accuracy as high as ± 5%.
Different from the built-in MOS scheme, the CXLE83176 adopts an external power MOS tube design, and drives the external MOS through the GATE pin, which enhances the power flexibility and heat dissipation capacity of the system. The chip integrates a high-voltage start-up circuit without an external VCC capacitor and a start-up resistor, which greatly simplifies the peripheral circuit and reduces the overall cost.
In terms of protection mechanism, the CXLE83176 has the functions of cycle-by-cycle over-current protection (OCP), output over-voltage protection (OVP), over-temperature regulation (OTR), CS resistor short-circuit protection and output open-circuit/short-circuit protection to fully ensure the stable operation of the system under various abnormal conditions.
2. Key Features and Benefits
1. No stroboscopic analog dimming
The CXLE83176 adopts analog dimming control technology, supports PWM dimming signal input of 500Hz ~ 4kHz, and the dimming is smooth and does not flicker. It is suitable for intelligent lighting systems with high light quality requirements.
2. High precision constant current output
The chip has a built-in high-precision current sampling circuit, and the output current can be accurately set through an external sampling resistor (Rcs) to ensure the stability of the LED current.
3. External MOS Design
By driving the external power MOS through the GATE pin, the system can flexibly select MOS tubes according to the output power requirements, improving the overall power scalability and heat dissipation performance.
4. Comprehensive protection mechanisms
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Overtemperature Regulation (OTR): When the chip junction temperature exceeds 140°C, the output current is automatically reduced to prevent overheating damage.
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Output Overvoltage Protection (OVP): Set the protection threshold through the external resistor to ensure the safety of the system in the open circuit state.
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Cycle-by-Cycle Overcurrent Protection (OCP): Real-time monitoring of inductor current to avoid overload risk.
3. key electrical parameters and package information
The CXLE83176 adopts SOP8 package, which has good heat dissipation performance and welding process adaptability. The main electrical parameters are as follows:
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Starting voltage：VHV_ON ≥ 9V
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Turn-off voltage: Vhv_off ≤0. 7V
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PWM dimming frequency：0.5kHz~4kHz
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Peak Current Detection Threshold：VCS_TH = 300mV
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over-temperature regulating point：TOTR = 140°C
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Maximum drive current：Isource = 170mA
4. working principle and circuit design
1. Startup and power supply
After the system is powered on, the chip supplies power to the internal circuit through the HV pin. When the HV voltage is higher than 9V, the chip starts to work; when it is lower than 7V, it will automatically shut down to ensure that there is no malfunction in the low voltage state.
2. Constant current control mechanism
CXLE83176 achieves cycle-by-cycle peak current control by sensing the CS pin voltage. When the CS voltage reaches the threshold VCS_TH, the external MOS is turned off; the inductor current is turned on again after being reduced to zero. The output current calculation formula is:
where VCS_TH is in mV and RCS is in ohms. CS pin is equipped with 350ns front-end blanking time, which effectively suppresses the noise interference at the turn-on moment.
3. Inductance selection and system frequency
The chip works in critical conduction mode (CRM), and the inductance value affects the operating frequency and demagnetization time of the system. The on-time and off-time are:
The switching frequency of the system is proportional to the input voltage, and the selection of the inductance value needs to take into account the demagnetization time and the accuracy of the output current to avoid entering the non-ideal conduction mode.
4. PWM dimming mechanism
The chip supports PWM signal input from 500Hz to 4kHz, and the average LED current changes linearly with the duty cycle. No external RC filter circuit is required, and the dimming response is fast and there is no delay.
5. Output overvoltage protection
Through the OVP pin external resistor RovP can set the output overvoltage protection point, its calculation formula is:
Where KOVP is the OVP setting coefficient, a typical value is 12.5 V/H.
5. PCB Design Guide
To ensure system stability and EMI performance, it is recommended to pay attention to the following points in PCB design:
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Sampling Resistor Layout: The trace from CS pin to the sampling resistor should be as short as possible, and connected to the Bulk capacitor ground terminal by star or multi-point grounding.
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High voltage isolation: HV pin should be away from CS, PWM, OVP and other low-voltage signal lines and components.
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OVP RESISTOR LOCATION: RovP should be close to the OVP pin and away from the high-voltage switch node.
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power loop optimization: Reduce the power loop area to reduce EMI radiation and improve the anti-interference ability of the system.
6. typical application scenarios
CXLE83176 widely used in the following LED lighting products:
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LED bulb lamp
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LED ceiling lamp
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Intelligent dimming lamps and lanterns
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Other Non-Isolated Buck LED Driver Systems
Its external MOS design is especially suitable for high-power LED lighting applications, with the right MOS tube can achieve higher efficiency and better heat dissipation.
7. epilogue
With its high-precision constant current output, no stroboscopic PWM dimming, flexible external MOS architecture and comprehensive protection mechanism, the CXLE83176 provides a reliable and efficient drive solution for LED intelligent lighting systems. Whether upgrading traditional lighting or developing new smart lamps, the chip can help engineers achieve the best balance between performance and cost.
For CXLE83176 samples, technical information or application support, welcome to visitJTM-IC official websiteOr contact our technical team. JTM-IC have always been committed to providing global customers with high-quality, high-reliability integrated circuit products and solutions to help your project success.
