Step-Up Converter is ideal for Portable OLED Applications

As portable system designers move to OLEDs to take advantage of their thin form factor, lower power requirements, and wider viewing angle, they need step-up converters with a fast transient response and ‘zero’ leakage when not active to preserve battery life.

The AAT1230 is a 2MHz, 18V, 100mA step-up converter optimised for powering both organic LED (OLEDs) and general purpose LCD and CCD modules in portable systems. Using an advanced architecture developed by AnalogicTech, the AAT1230 delivers fast transient response and excellent load isolation while dramatically reducing system footprint.

Stability is a major concern in boost converter design. To address this issue, the AAT1230 combines a high frequency converter capable of reaching 2MHz with a hysteretic feedback loop-based control mechanism to support very fast transient response and remain stable over a wide load and input voltage range without additional compensation components. Moreover, the device’s high switching frequency enables the use of extremely small inductors and capacitors.

The AAT1230 also adds a new feature designed to address the leakage current losses inherent when conventional step-up converters drive OLEDs. To minimise current losses, designers using conventional boost converters typically use a load switch and control circuitry to disconnect the converter when the OLED module is disabled. AnalogicTech’s AAT1230 adds a true load disconnect function which isolates the load from the power source when EN/SET is pulled low. Leakage current is less than 1µA. This function allows designers to simplify their design by eliminating the load switch and control circuitry.

To support most current OLED modules, the output voltage on the AAT1230 can be dynamically set by activating either of two reference levels via the SEL logic pin. As future generation OLED applications become increasingly sophisticated, designers will require more complex control mechanisms. A dynamic output control function in the AAT1230 allows designers to easily and simply make that transition. Through an enable set pin, this feature allows designers to program output brightness to any of 16 different levels. The AAT1230 also offers a number of safety features including cycle-by-cycle current limit, short-circuit, and over-temperature protection circuits. Specified over the -40 to +85 degrees C temperature range, the AAT1230 is available in a Pb-free, 12-pin TSOPJW package.