Inductive boost DC/DC converter powers series-connected white LEDs

The AAT1231 is a high frequency, high efficiency inductive boost DC/DC converter for controlling white LEDs in portable systems operating from single-cell lithium-ion/polymer batteries. Delivering 50mA up to 24V, the device is capable of driving up to six white LEDs in series or up to 12 white LEDs in a parallel/series configuration using AnalogicTech’s digital Simple Serial Control single-wire interface.



LED output current on the AAT1231 is controlled using AnalogicTech’s S2Cwire interface in 16 linear steps. By changing the feedback voltage with the SEL pin, designers can extend the output voltage another 16 levels. This allows designers to ‘set and forget’ the output across a total of 26 steps (after overlap) from 7.5% to 100%. Digital control improves display readability by providing constant flicker-free LED output.



The AAT1231’s high, 2MHz switching frequency provides fast response to load transients and permits the use of small external components including a 2.2µH inductor. The AAT1231 delivers an overall efficiency up to 82%. The device also adds a true load disconnect feature which completely isolates the load from the power source. By reducing leakage current to less than 1µA, this function extends battery life and system standby time.



AnalogicTech’s AAT1231 also offers a wide variety of standard protection features, including integrated soft-start, current limit, over-temperature, and over-voltage protection. Specified over the -40 to +85 degrees C temperature range, the AAT1231 is immediately available in a Pb-free, 12-pin TSOPJW package.