Product category:
Power Supply ICs and Controllers
News Release from: Advanced Analogic Technologies | Subject: AAT3175
Edited by the Electronicstalk Editorial
Team on 05 October 2005
Charge pump boosts camera flash
intensity
The AAT3175 is a low-noise high-frequency current-mode charge pump for white LED flash applications.
Available now from Advanced Analogic Technologies, the AAT3175 is a low-noise high-frequency current-mode charge pump for white LED flash applications As AnalogicTech's first dedicated current mode fractional/doubler charge pump for camera flash applications, the AAT3175 is capable of driving up to three flash LEDs at 300mA total current with current sharing from a 2.7 to 5.5V source
This article was originally published on Electronicstalk on 19 Sep 2008 at 8.00am (UK)
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"As the number of megapixels increases in camera phones, so does the brightness requirement of the white LED photo flash".
"Therefore, more accurate current control is required".
"Current sink charge pumps are specifically designed to meet this requirement", said Kin Shum, Director of Strategic Marketing for AnalogicTech.
"For flash current of 300mA or below, we believe that the AAT3175 is the best-in-class driver on the market, and the 1x/1.5x/2x conversion offers excellent efficiency in both flash and torch/movie mode".
The trimode device maximises efficiency by combining a load switch (1x), fractional (1.5x), and doubling (2x) capability with an internal sensing circuit to match output to LED requirements.
The new charge pump is also completely programmable via AnalogicTech's innovative S2Cwire (simple serial control) digital interface.
The single wire interconnect is used to enable, disable, and set current for all LEDs across 16 current levels, capable of controlling movie-mode lighting or camera flash.
With four current sink channels (100/50/50/100mA capability), the AAT3175 can accommodate single, two-in-one or three-in-one LEDs with high-precision current matching.
Operating at a 1MHz switching frequency, the AAT3175 requires just two 1uF flying capacitors and two small 1uF capacitors on the input and output pins.
The device also features integrated protection for output short-circuit conditions and auto-disable for load short-circuit protection on any individual channel.
Soft-start circuitry prevents excessive inrush current during startup.
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