通用高亮度LED驱动芯片SMD802

Universal High Brightness LED Driver SMD802 FEATURES特性 _ > 90% Efficiency _ Universal rectified 85 – 265VAC input range _ ConSTant-current LED driver _ Applications from a few mA to more than 1A Output _ LED string from one to hundreds of diodes _ PWM Low-Frequency Dimming via Enable pin _ Input Voltage Surge ratings up to 500V _ Internal thermal overloAD protection   DESCRIPTION简介 The SMD802 is a PWM high-efficiency LED driver control IC. It allows efficient operation of High Brightness (HB) LEDs from voltage sources ranging from 85VAC up to 265VAC. The SMD802 controls an external MOSFET at fixed switching frequency up to 300kHz. The frequency can be programmed using a single external resistor. The LED string is driven at constant current rather than constant voltage, thus providing constant light output and enhanced reliability. The output current can be programmed between a few milliamps and up to more than 1.0A. SMD802 uses a rugged high voltage junction isolated process that can withstand an input voltage surge of up to 500V. Output current to an LED string can be programmed to any value between zero and its maximum value by applying an external control voltage at the linear dimming control input of the SMD802. The SMD802 provides a low-frequency PWM dimming input that can accept an external control signal with a duty ratio of 0-100% and a frequency of up to a few kilohertz.   APPLICATIONS应用 _ AC/DC LED Driver applications _ RGB Backlighting LED Driver _ Back Lighting of Flat Panel DISPlays _ General purpose constant current source _ Signage and Decorative LED Lighting _ Chargers     PACKAGE INFORMATION封装信息 PIN FUNCTIONS引脚功能 1 VIN: Input voltage 2 CS:  Senses LED string current 3 GND : Device ground 4 GATE : Drives the gate of the external MOSFET 5 PWM_D: Low Frequency PWM Dimming pin, also Enable input. Internal 100Kohm pull-down to GND 6 VDD: Internally regulated supply voltage. 7.5V nominal. Can supply up to 1 mA for external circuitry. A sufficient storage capacitor is used to provide storage when the rectified AC input is near the zero crossings. 7 LD: Linear Dimming by changing the current limit threshold at current sense comparator 8 ROSC: Oscillator control. A resistor connected between this pin and ground sets the PWM frequency.   TYPICAL APPLICATIONS应用电路