AAT1409 Datasheet | Analogic Corporation

Data Sheet.in PRODUCT DATASHEET Switch Reg TM 8 Channel LED Backlight Driver with Integrated Boost and High Frequency Direct PWM Dimming General Description The AAT1409 is a highly integrated, high efficiency LED backlight solution for notebook puters, monitors and portable TVs. The device operates from DC inputs, cigarette lighter adapters, or multi-cell Li-ion batteries over the 4.5V to 26V voltage range. An integrated boost (step-up) converter provides up to 45V output for driving series LEDs. Eight precision current sinks are programmed up to 45m A per string through one external RSET resistor, supporting up to 881 white LEDs at 360m A total output current. LED strings may be disabled or operated in parallel for increased drive capability. The boost output voltage is set by the LED string with the highest voltage requirement, allowing a wide range of LED characteristics. The PWM dimming range at 100Hz is up to 1,000:1. The boost switching frequency is selectable (up to 1.3MHz) to allow optimum efficiency and the smallest external L/C filtering ponents. Alternatively, the device may be synchronized to an external clock. 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 LED strings. The unique high voltage current sinks prevent damage resulting from shorted LEDs. The AAT1409 is available in the Pb-free, thermally enhanced 24-pin 3x4 TQFN package. - - - - - - - Features - - - - - - VIN Range: 4.5V to 5.5V / 5.0V to 26.0V LX Rated to 50V Maximum IOUT: 360m A Up to 92% Efficiency High Efficiency Light-Load Mode 8 LED Current Sinks up to 45m A/each - ±2% Accuracy (21m A) - ±2% Matching (21m A) Flexible Configurations - Disable or Parallel Switching Frequency Options - 675k Hz or 1.3MHz - Synchronize to System Clock PWM Direct Dimming Input - Up to 100k Hz Prevents Audio Interference -...