austriamicrosystems Launches Small Fully Integrated 700mA Flash LED Driver
austriamicrosystems AG announced that it has launched the AS3685, an ultra-small and fully integrated 700mA charge-pump-based flash LED driver. The company claims that the AS3685 is the world’s smallest fully integrated charge-pump based flash LED driver offering 700mA flash current and is targeted at camera flash applications in mobile phones.
The wafer-thin AS3685 measures only 2 x 1.5mm and less than 600µm in height, it takes up just 14mm2 of PCB space, including four external components. Following 0.25mm PCB design rules, the company claims the AS3685 uses less than 50% of the space required by its closest competitor. The only external components that the AS3685 needs are low cost capacitors and resistors. This is intended to give the device an excellent overall bill of material (BOM) and the ability to outperform competing inductive solutions by at least 20%.
To avoid excessive current being drawn from the battery if the phone’s power amplifier becomes active while a picture is being taken – a situation potentially causing the phone to shut down due to a related voltage drop – the AS3685 can reduce the flash current to the significantly lower flash current within less than a microsecond. This prevents dropped calls without compromising photo quality. Other safety features include a built-in flash LED time-out function that guarantees flash shutdown via a built-in factory-programmable timer, typically 800ms. This prevents the destruction of the LED or damage to the mobile phone from excessive heat produced by the LED.
The AS3685 comes with a multi-mode, simple 2-pin interface incorporating off, indicator, flashlight and flash operating modes. The AS3685B product variant features a single-wire interface allowing the flash current to be set in any of 18 different steps depending on actual operating and environmental conditions. This allows to dynamically reduce the flash current during MP3 playback or at low battery conditions, thereby extending battery life.
The AS3685 is available in WL-CSP3x4 packaging. It is currently in trials and will be released to mass production in February 2007.
