Photo flash and backlight driver ICs optimise power efficiency in phone designs

Operating from a 2.7V to 5.5V input voltage, the AAT3176 flash driver IC supplies up to 500mA output current. The dual mode charge pump maximizes power efficiency by supporting both 1X and 2X operation and can be programmed across 16 distinct steps via AnalogicTech’s patented S2Cwire™ (Simple Serial Control) interface. Delivered in the industry’s smallest package for a 500mA flash driver IC – 20percent smaller than comparable devices – the AAT3176 allows designers to build highly compact camera lighting solutions.

To maximize design flexibility and minimize programming time, the AAT3176 uses separate external resistors to set maximum flash and movie-mode current. To protect the integrity of the device, the driver features a thermal management system that includes open and short-circuit protection and automatic soft-start circuitry. A load disconnect feature extends battery life by disconnecting the load during shutdown and reducing quiescent current to less than 1.0uA.

The AAT3351 is a high efficiency charge pump capable of driving up to four White LEDs at up to 30mA each. The dual-mode fractional charge pump automatically switches between 1X and 1.5X modes based on input voltage, LED forward voltage and load current to maximize efficiency. A 1MHz switching frequency helps minimize external component size.
To smooth transitions between brightness levels, the device uses AnalogicTech’s S2Cwire™ serial digital interface to enable, disable and set current to any of 32 levels. LED current output accuracy is +/-10percent and LED current matching is 3percent. The AAT3351 also adds automatic soft-start circuitry and built-in short-circuit protection.

Over the last few years AnalogicTech has built up a comprehensive product line of lighting solutions for cell phone and mobile device designs by constantly pursuing innovative approaches to the problems designers face. By improving power efficiency, reducing board footprint and simplifying LED control while preserving the flexibility and safety features in existing products, these latest charge pump-based devices take those achievements to a new level.

Both ICs are qualified across the -40 to +85 degrees C temperature range. The AAT3176 is available in a compact 2.2 x 2.2-mm, 10-pin TDFN package, and the AAT3351 comes in either a 14-pin TSOPJW or 12-pin TDFN33 package.