LEDs, Flash-Lamp Chips View For Cell-Cam Design-Ins

Next-generation cell phones will use xenon flash lamps or super-bright LEDs for the flash function in integrated cameras.

For xenon lamps, with an external 5.8- by 5.8- by 3-mm transformer, Linear Technology's photoflash-capacitor charger can charge an external 100-µF capacitor to 320 V in as little as 4.6 s (see the figure, a).

For LEDs, with the addition of two 1-µF and two 10-µF ceramic capacitors, Analogic Tech's charge pump can deliver 500 mA of pulsed current at 4.5 V to a flash array without an inductor (see the figure, b).

Analogic's AAT3112 uses a compact 16-pin 3- by 3-mm QFN package. It costs $1.41 each in 1000-piece quantities. Linear's LTC3468 comes in a low-profile SOT-23 package and is priced at $1.95 in 1000-unit quantities.