Product Overview

CXLE86247 is an efficient boost constant current LED driver that integrates high-frequency power transistors and Schottky diodes, supporting;2.5V~25V wide input voltage, can accurately drive 1-8 strings of LEDThe chip adopts 1.2MHz constant switching frequency  With built-in frequency compensation circuit, it significantly reduces the size and cost of peripheral components, while optimizing PCB space utilization. Its;Design of 200mV low feedback voltage  Significantly reduce the power consumption of external sampling resistors, combined with EN pins;TTL power on/off control  With 0%~100% PWM stepless dimming  Specially designed for ultra-low static current (shutdown current of only 3μ A) and miniaturized devices.

Core advantages and characteristics

Efficient Design

• Wide pressure adaptation: Supports 2.5V~25V input, compatible with battery power supply and multi scene power supplycRo嘉泰姆

• High power outputMaximum 1A switch current, with an efficiency of over 88%cRo嘉泰姆

• High frequency integrationBuilt in high-frequency power transistor and Schottky diode, supporting boost/SEPIC topology, flexible adaptation to complex circuitscRo嘉泰姆

Flexible control and energy conservation

• Smart DimmingContinuous PWM brightness adjustment through EN pin (duty cycle 0~100%)cRo嘉泰姆

• ultra-low power3μ A ultra-low shutdown current, extending the battery life of portable devicescRo嘉泰姆

Multiple protection mechanisms

• System level protectionLED open circuit protection, thermal shutdown protectioncRo嘉泰姆

• high reliabilityClass 3A HBM ESD protection (>8kV) ensures anti-static capabilitycRo嘉泰姆

Miniaturization packaging

• Compact solutionSOP8-EP package (enhanced heat dissipation type), suitable for micro devices with limited spacecRo嘉泰姆
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Typical application scenarios

• Backlight for smart device display screens(Mobile phones, tablets, car screens)cRo嘉泰姆

• Wearable and portable electronics(Smartwatches, TWS earphones, health monitoring devices)cRo嘉泰姆

• Digital imaging equipment(Camera flash, fill light)cRo嘉泰姆

        Industrial handheld terminal(PDA, barcode scanner, auxiliary display)cRo嘉泰姆
Bill of MaterialscRo嘉泰姆

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DEMO physical imagecRo嘉泰姆

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PCB layoutcRo嘉泰姆

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PCB wiring rules;cRo嘉泰姆

          1. Shorten the discontinuous current circuit: the positive terminal of the output capacitor is close to the OUTN of the chip, and the negative terminal of the output capacitorcRo嘉泰姆
    Approaching the GND of the chip to further reduce its parasitic inductance, minimize glitch voltage, and improve system stability;cRo嘉泰姆
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      2. The ceramic capacitor at the input end is used to filter out high-frequency voltage spikes and provide pure power to the internal logic circuit of the chip,cRo嘉泰姆
          Ceramic capacitors are located near the VIN and GND pins of the chip;cRo嘉泰姆
      3. Power lines such as VIN, SW, OUTP, OUTN, GND, etc. should be treated with copper plating as much as possible to achieve thickness, length, and straightness;cRo嘉泰姆
      4. CS feedback wiring should be kept away from inductor, SW and other switch signal nodes, and preferably surrounded by GND wiring.cRo嘉泰姆
Application InformationcRo嘉泰姆

Input capacitor selection;cRo嘉泰姆
        In continuous mode, the input current of the converter is a set of square waves with a duty cycle of approximately (VOUT-VIN)/VOUT. To prevent large transient voltages, it is necessary to select low ESR (equivalent series resistance) input capacitors for maximum RMS current requirements. For most applications, a 1uF input capacitor is sufficient, and it should be placed as close to the chip as possible. The maximum RMS capacitor current is given by the following equation:cRo嘉泰姆
                            IRMS≈ 0.3*∆ILcRo嘉泰姆
Among them, the maximum average output current IMAX is equal to the sum of the peak current and 1/2 of the peak ripple current, that is, IMAX=ILIM+△ IL/2.cRo嘉泰姆
Output capacitor selection;cRo嘉泰姆
          Low ESR capacitors should be selected at the output end to reduce output ripple voltage. Generally speaking, once the ESR of the capacitor is met, the capacitor is sufficient to meet the demand. The ESR of any capacitor, along with its own capacity, will create a zero point for the system. The larger the ESR value, the lower the frequency range where the zero point is located. Ceramic capacitors, on the other hand, have a zero point at a higher frequency, which can usually be ignored and is a better choice. However, compared to electrolytic capacitors, large capacity and high voltage ceramic capacitors have a larger volume and higher cost. Therefore, using ceramic capacitors with a capacitance of 0.1uF to 1uF in combination with low ESR electrolytic capacitors is a good choice. The output voltage ripple is determined by the following equation:cRo嘉泰姆
                      △VOUT≈ △IL* [ESR+1/(8*F*COUT)]cRo嘉泰姆
F in the formula: switching frequency, COUP: output capacitor, △ IL: ripple current in the inductor.cRo嘉泰姆
Inductance selection;cRo嘉泰姆
          Although inductors do not affect the operating frequency, the inductance value has a direct impact on the ripple current. The inductance ripple current △ IL decreases with the increase of inductance value and increases with the increase of VIN and VOUT. A reasonable starting point for setting ripple current is △ IL=0.3 * ILIM, where ILIM is the peak switch current limit. In order to ensure that the ripple current is below a specified maximum value, the inductance value should be selected according to the following formula:cRo嘉泰姆
                          L=VIN*D*(1-D)/0.3*IOUT*F    cRo嘉泰姆
Typical characteristicscRo嘉泰姆

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Selection Guide for Related Chips;               More similar products .....cRo嘉泰姆

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