Jan 31 2008
Advanced Analogic Technologies, Inc., a developer of power management semiconductors for mobile consumer electronic devices, announced today the AAT1239-1, a high frequency, high efficiency constant current boost converter capable of driving up to 10 white LEDs (WLEDs) connected in series.
Designed for backlight applications in PNDs, eDictionaries, Electronic Photo Frames and cellular handsets, the new driver IC uses AnalogicTech's proprietary Simple Serial Control (S2CWire) single-wire interface to dramatically reduce the display flicker that occurs with commonly-used low frequency PWM control schemes.
"As portable systems designers continually extend the feature set in their products, they need to use increasingly sophisticated lighting functions to support those new capabilities," said Phil Dewsbury, product line manager for AnalogicTech. "By driving up to 10 WLEDs in a serial string, the AAT1239-1 simplifies the use of larger LCD panels in a wide array of battery-powered portable devices."
Twenty-six Brightness Levels
Operating off a 2.7V to 5.5V input range, the AAT1239-1 delivers a maximum continuous output of 40V @ 30 mA and delivers a constant LED current for up to 10 WLEDs in series. An integrated soft start function eliminates output voltage overshoot across the full input voltage range.
The single-wire S2CWire interface controls WLEDs across 26 discrete current steps. It requires no additional circuitry. The AAT1239-1 also features a true load disconnect function that isolates the load from the power source while in the OFF or disabled state. By guaranteeing <1.0 uA shutdown current, this feature extends battery life by eliminating leakage current in power-limited portable applications.
The new WLED driver IC offers efficiency levels up to 82%. A high 2 MHz switching frequency provides very fast response and helps reduce end product footprint by allowing the use of very small external inductors and capacitors.
The AAT1239-1 also offers short-circuit, overvoltage and over-temperature protection.
Price and Availability
Qualified across the -40 C to +85 C temperature range, the AAT1239-1 is available in a Pb-free, 12-pin TSOPJW package. The IC sells for $1.08 in 1K quantities.