|[March 04, 2013]
Brighter, clearer images from mobile phone cameras as ams introduces intelligent flash LED driver
UNTERPREMSTAETTEN, Austria --(Business Wire)--
ams AG (SIX: AMS), a leading worldwide designer and manufacturer of
high-performance analog ICs for consumer & communications, industrial &
medical and automotive applications, today introduced a new intelligent
LED driver for mobile phone cameras that maximizes the brightness of the
flash without causing the phone's battery to fall below its minimum
The AS3649 LED driver uses an innovative "diagnostic pulse" - a burst of
controlled high current lasting a few milliseconds - immediately before
every flash operation. During this pulse the device measures the
momentary voltage across the terminals of the phone's battery. On the
basis of this measurement, it reports a value for the highest flash
drive current the battery can sustain, up to a maximum of 2.5A, without
dropping below its minimum voltage and triggering the phone to reset
itself during the main flash.
Drawing on advanced analog sensing technology developed by ams, the
AS3649 measures the battery voltage and current with high accuracy,
enabling it to precisely calibrate the optimal LED drive current under
any given conditions.
Mobile phones that use the AS3649 can therefore generate the brightest
possible flash light, without the need for a bulky auxiliary power
source such as a super-capacito. Users benefit from higher image
quality and higher resolution. When taking pictures of fast-moving
objects, a brighter flash enables the use of faster shutter speeds for
sharper, clearer pictures.
The introduction of the LED driver AS3649 also allows mobile phone
manufacturers to markedly reduce the engineering and software
development effort involved in flash LED implementation. Today,
manufacturers exhaustively test the operation of each mobile phone
model's LED flash system under all possible operating conditions, and at
all operating voltages. The results of these tests are encoded in a
software look-up table stored on the phone. Whenever the camera calls
for the flash to be operated, the phone's processor must read from the
look-up table an estimate for a safe drive current value.
The diagnostic pulse technique implemented by the AS3649 eliminates
virtually all of this engineering effort, since it is able to measure
the actual behavior of the battery at the time of use, instead of
estimating it beforehand on the basis of sampled test results.
Supplying up to 2.5A to a single LED or up to 1.25A each to two LEDs,
the AS3649 is well positioned for next-generation phone cameras using
higher-brightness LEDs. The device's current-source architecture
provides for effective thermal management, and an on-board NTC
(temperature sensor) automatically reduces the current to the LED if it
exceeds a programmable temperature threshold.
Ronald Tingl, Senior Marketing Manager at ams, said: "Consumers look
carefully at camera performance when choosing a mobile phone - it is a
key differentiator. By using the AS3649, handset manufacturers can
achieve the best possible lighting for pictures taken in dark
conditions, and at the same time benefit from eliminating the huge
effort involved in qualifying all components stressed by high LED flash
Price & Availability
The AS3649 intelligent flash LED driver is available in volume
production now. It is priced at $0.78 for 1,000 pieces.
A demonstration board for the AS3649 is available. For further
information on the Camera Flash LED driver AS3649 or to request samples,
please visit www.ams.com/Camera-Flash-LED-Driver/AS3649
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