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Analogic公司的AAT1451是四路高集成高效白光LED驅動器,主要用于筆記本電腦,上網本,監視器和手提TV的LCD背光的LED驅動.器件的輸入電壓從5V到26V,可從DC,點煙適配器或多個鋰電池輸入,集成的升壓轉換器提供高達50V的輸出,每串LED電流高達30mA可編程,120mA總輸出電流可驅動多達481個LED.效率高達93%,主要用在監視器, 筆記本和上網本電腦,手提DVD播放器,手提TV和白光LED背光.本文介紹了AAT1451主要特性, 方框圖, 典型應用電路圖以及評估板電路圖和材料清單, PCB布局圖. AAT1451 | Four LED Strings–High Efficiency White LED Driver for LCD Backlighting The AAT1451 is a highly integrated, high efficiency LED backlight solution for notebook, netbook computers, monitors and portable TVs. The device operates from DC inputs, cigarette adapters or multi-cell Li-ion batteries in the voltage range from 5V to 26V. An integrated boost (step-up) converter provides a high voltage output up to 50V for driving series LEDs. Four precision current sinks are programmable up to 30mA per string through one external RSET resistor, supporting up to 481 white LEDs at 120mA total output current. The boost output voltage is determined by the highest total forward voltage of the LED strings, allowing for a wide range of LED characteristics. Each string is PWM dimmed with 90 degree phase shift to minimize ripple currents, and filter capacitor sizes. The PWM input frequency range is 100Hz to 10kHz with a dimming range of 256:1. The integrated boost regulator switching frequency is programmable from 600kHz to 1MHz by external resistor for optimum efficiency and the smallest external L/C filtering components. Boost current mode control provides fast response to line and load transients. Integrated light-load mode ensures highest efficiency across the entire load range. Fault tolerant circuitry extends system life by disabling open and shorted LED(s) strings. The unique high voltage current sinks prevent damage resulting from shorted LEDs. The FAULT pin indicates the presence of shorted LEDs or over-temperature conditions. The AAT1451 is available in a Pb-free, thermally enhanced 16-pin 3x4 TDFN package. AAT1451主要特性: • VIN Range: 5V to 26V • Integrated 50V Boost Converter ▪ Maximum IOUT: 120mA ▪ Programmable Switching Frequency • 600kHz to 1MHz ▪ Up to 93% Efficiency ▪ High Efficiency Light-Load Mode • Four White LED Strings ▪ Programmable Max Current Sink up to 30mA Each ▪ ±2% Accuracy (22mA) ▪ ±1.5% Matching (22mA) • Direct PWM Dimming ▪ Automatic Phase Shifting ▪ Fast Turn-On/Off • Integrated Fault Protection for ▪ Independent Disable of Open/Shorted LED(s) String(s) ▪ Over-Voltage ▪ Over-Temperature • FAULT Indication for Shorted LED(s) and Over-Temperature • Soft-Start Minimizes Inrush Current • TDFN34-16 Low Profile Package • -40℃ to +85℃ Temperature Range AAT1451應用: • Monitors • Notebook and Netbook Computers • Portable DVD Players • Portable TV • White LED Backlight 
圖1.AAT1451方框圖
圖2.AAT1451典型應用電路圖
圖3.AAT1451評估板電路圖 AAT1451評估板材料清單:
AAT1451評估板表面安裝電感:
AAT1451評估板表面安裝電容:
圖4.AAT1451評估板PCB布局圖 詳情請見: http://www.analogictech.com/products/product_part.php?PID=361 |
