CXLE83175X is a high-precision LED constant current driver chip that supports PWM input dimming. It adopts a full-range analog dimming control mode to effectively avoid stroboscopic and noise problems. Its dimming range is 1% ~ 100, suitable for a wide input voltage range of 85VAC ~ 270VAC, with excellent linear adjustment and load adjustment rate, to ensure that the LED current output accuracy of up to 5%.
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[ CXLE83175 ]"
CXLE83175X: high precision PWM dimming stroboscopic-free LED driver chip
With the increasing popularity of intelligent lighting, the performance of LED driver chips directly affects the stability, dimming effect and service life of lamps. As a high-precision non-isolated step-down LED constant current driver chip designed for no stroboscopic and noise-free intelligent lighting applications, CXLE83175X has become an ideal choice for LED bulb lamps, ceiling lamps and other lighting products with its excellent dimming consistency, high integration and multiple protection mechanisms. This article will analyze the technical characteristics, working principles and application design points of the CXLE83175X in depth to help engineers better understand and apply the chip.
1. Product Overview
CXLE83175X is a high-precision LED constant current driver chip that supports PWM input dimming. It adopts a full-range analog dimming control mode to effectively avoid stroboscopic and noise problems. Its dimming range is 1% ~ 100, suitable for a wide input voltage range of 85VAC ~ 270VAC, with excellent linear adjustment and load adjustment rate, to ensure that the LED current output accuracy of up to 5%.
The chip integrates 500V high-voltage power MOS tube, without external VCC capacitor and starting resistor, which greatly simplifies the peripheral circuit design and reduces the system cost. At the same time, the CXLE83175X has built-in multiple protection functions, including cycle-by-cycle over-current protection (OCP), output over-voltage protection (OVP), over-temperature regulation (OTR), CS sampling resistor short-circuit protection and output open/short-circuit protection, which comprehensively improves the reliability and safety of the system.
2. core features and benefits
1. High integration and simplified design
CXLE83175X internal integrated 500V MOS tube, and built-in high voltage start circuit, no external VCC capacitor and start resistor. This not only reduces the number of components, but also reduces the complexity of PCB layout, which is particularly suitable for compact LED lamp designs with limited space.
2. No stroboscopic analog dimming
The chip adopts analog dimming control mode and supports PWM signal input of 500Hz ~ 4kHz. The dimming is smooth and flicker-free, and is suitable for intelligent lighting scenes with high light quality requirements. The PWM pin eliminates the need for an external RC filter circuit, further simplifying the design.
3. High precision constant current output
Through the built-in high-precision current sampling circuit, the CXLE83175X can achieve accurate LED constant current output. The output current can be flexibly set by an external sampling resistor (Rcs) to meet the driving requirements of different power LEDs.
4. Comprehensive protection mechanism
The chip has perfect protection functions. For example, over temperature regulation (OTR) can automatically reduce the output current when the junction temperature exceeds 140°C to prevent overheating damage. The output overvoltage protection (OVP) can set the protection threshold through an external resistor to ensure the safe operation of the system under abnormal conditions such as open circuit.
3. electrical parameters and package selection
The CXLE83175X provides SOP8 and DIP 350.00g package forms to meet different heat dissipation and installation requirements. The key electrical parameters are as follows:
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Starting voltage：VHV_ON ≥ 9V
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Working current: Typical 380 & micro;A
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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 threshold：TOTR = 140°C
Users can choose the appropriate model (such as CXLE83175A/B/C/D/E) and package according to the heat dissipation conditions and power level in the actual application.
Detailed explanation of 4. working principle
1. Startup and power supply
After the system is powered on, the chip supplies power to the internal circuit through the HV pin without external VCC capacitor. The gate drive of the power MOS is directly provided by the high-voltage power supply circuit, which simplifies the power supply design.
2. Constant current control mechanism
CXLE83175X achieves cycle-by-cycle peak current control by sensing the CS pin voltage. When the CS voltage reaches the threshold VCS_TH, the power transistor turns off; the inductor current drops to zero and then turns on again. The output current calculation formula is:
where VCS_TH is in mV and RCS is in ohms.
3. Inductance selection and latent magnetic control
The chip works in critical conduction mode (CRM), and the choice of inductance value is very important to the performance of the system. Too large or too small inductance will affect the demagnetization time, which will cause the output current to deviate from the design value. It is recommended to select a reasonable type according to the input and output voltage, target current and other parameters.
4. PWM dimming and over temperature regulation
The PWM signal directly controls the average LED current, enabling smooth dimming of 1 to 100 percent without filtering. When the chip junction temperature exceeds the set threshold, the over-temperature adjustment function automatically starts to gradually reduce the output current to ensure that the system temperature is stable within a safe range.
5. Output overvoltage protection
The output overvoltage protection point can be set through the external resistor of OVP pin (RovP), and its calculation formula is:
where KOVP is the OVP setting coefficient with a typical value of 12.5 V/H.
5. PCB Design Recommendations
To ensure system stability and EMI performance, PCB layout should pay attention to the following points:
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sampling resistance loop: 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 grounding or multi-point grounding.
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High voltage isolation: HV pin should be away from CS, PWM, OVP and other low-voltage pins and components to avoid noise interference.
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OVP resistor layout: RovP should be close to the OVP pin and away from high voltage noise.
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Heat dissipation and EMI balance: DRN pin copper-clad area should be appropriate, too large is conducive to heat dissipation but may deteriorate EMI performance.
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power loop optimization: Reducing the power loop area helps reduce EMI radiation.
6. typical application scenarios
CXLE83175X are widely used in all kinds of LED lighting products, including:
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LED bulb lamp
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LED ceiling lamp
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Other intelligent dimming lamps
Its high precision, no stroboscopic, high reliability characteristics, make it become the modern home, commercial lighting and intelligent lighting system preferred driving scheme.
7. epilogue
With its high integration, precise dimming performance and perfect protection mechanism, the CXLE83175X provides an efficient and reliable solution for LED lighting design. Whether it is the upgrade of traditional lamps or the development of new intelligent lighting, the chip can help engineers achieve better system performance and lower overall cost.
For more information about CXLE83175X technical information, sample application or purchase information, please visitJTM-IC official websiteOr contact our technical support team. JTM-IC are committed to providing global customers with high-quality integrated circuit solutions to help your products stand out in the market competition.
