ANALOGICTECH - AAT1239-1 40V Step-Up Converter for 4 to 10 White LEDs handbook
The AAT1239-1 is a high frequency, high efficiency constant current boost converter capable of driving up to ten (10) series-connected white LEDs or 40V. It is an ideal power solutions for backlight applications with up to ten white LEDs in series. The input voltage is 2.7V to 5.5V for single-cell lithium-ion/polymer (Li-ion) based portable devices. The LED current is digitally controlled across a 6x operating range using AnalogicTech’s Simple Serial Control™ (S2Cwire™) interface. Programmability across 26 discrete current steps provides high resolution, low noise, flicker-free, constant LED outputs. In programming AAT1239 operation, LED brightness increases based on the data applied at the EN/SET pin. The SEL logic pin changes the feedback voltage between two programmable ranges. The AAT1239-1 features a high current limit and fast, stable transitions for stepped or pulsed current applications. The high switching frequency (up to 2MHz) provides fast response and allows the use of ultra-small external components, including chip inductors and capacitors. Fully integrated control circuitry simplifies design and reduces total solution size. The AAT1239-1 offers a true load disconnect feature which isolates the load from the power source while in the OFF or disabled state. This eliminates leakage current.