Flash LED drivers offer best efficiency for next-generation smartphones

November 05, 2012 // By Christoph Hammerschmidt
Analog Devices introduced two flash LED drivers featuring best in class efficiency to extend battery life in smartphones and tablets and to limit the load on the battery during flash and torch events. The ADP1660 is a dual 750-mA (1500-mA total) flash LED driver available in a 2.0-mm x 1.6-mm 12-ball WLCSP package. The ADP1649 is a single 1000-mA LED driver available in a 2.0-mm x 1.5-mm 12-ball WLCSP package.

Equipped with the FETs with the industry's lowest Rds(on), the chips can help to minimise the current drawn from the battery during flash or torch mode - a critical property in today's smartphone applications where new features and higher data rates increasingly load down the battery, the company said. Besides the efficient hardware, the new ADP1649 and ADP1660 have further features, for example algorithms that adjust flash current autonomously during low battery conditions.

The ADP1649 and ADP1660 flash LED drivers reduce circuit board size by integrating a programmable 1.5-MHz or 3-MHz synchronous inductive boost converter which enables the use of a 1-mm-high, low-cost, 1-μH power inductor and 0603 case-size input and output capacitors. The two devices include I²C communication ports for added flexibility and safety control. The interface also enables the programmability of timers, currents and status bit readback.

A Tx masking feature is included to reduce the risk of overloading the battery during a simultaneous power amplifier (PA) transmission burst and flash event. The masking feature can be used to quickly reduce the flash LED current during the PA burst to maintain an acceptable load on the battery.

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