Product category:
Power Supply ICs and Controllers
News Release from: Advanced Analogic Technologies | Subject: AAT2848
Edited by the Electronicstalk Editorial
Team on 12 June 2008
Handset power chip runs flash and
backlight
Trimode charge pump driver IC supports both display backlighting and camera flash operations in mid-range camera phones.
New from AnalogicTech, the AAT2848 is a trimode charge pump driver IC for white LED backlight display and flash applications By integrating four backlight channels capable of driving up to 30mA each with two flash channels capable of driving up to 300mA each, or 600mA in parallel, in a small 3 x 3mm TQFN33-20 package, the device offers mid-range camera phone designers a highly attractive space-saving solution
This article was originally published on Electronicstalk on 16 Jun 2004 at 8.00am (UK)
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Until recently designers building mid-range camera phones featuring cameras with 2 to 5Mpixel resolution needed to use independent devices for backlight and flash functions.
By integrating into a single compact IC both the backlight function and flash output current levels one would expect only from a discrete flash driver IC, the AAT2848 helps handset designers reduce board space, minimise component count and simplify their design.
The AAT2848 is a trimode charge pump offering 1x, 1.5x and 2x operation.
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The IC drives four backlight LED channels at up to 30mA each using the charge pump in dual mode (1x and 1.5x) and two flash LED channels at up to 300mA each in trimode (1x, 1.5x and 2x).
To enable, disable and set LED current, the AAT2848 features two of AnalogicTech's patented Simple Serial Control (S2Cwire) serial digital interfaces.
For backlight functions the device can set current to any of 32 programmable levels.
The flash LED outputs can be set independently across 16 programmable levels.
Full scale current is independently set for backlight and flash using external resistors.
The driver IC also features an innovative fade-in/fade-out function that gradually increases backlight LED brightness from off to fully on across a 63-step linear progression.
Fade time is controllable by an external capacitor.
By replacing microprocessor-based software schemes for the same function, this feature offers a smoother transition to full brightness while reducing software overhead.
The device also adds a user-programmable safety timer to protect the flash LEDs from thermal damage.
This function can be used to terminate a flash event after a predetermined period of time.
Both the safety timer and flash/strobe operation is enabled via a separate flash enable pin.
The AAT2848 also comes with integrated short-circuit and overtemperature protection.
Soft start circuitry prevents excessive inrush current at start-up and during mode transitions.
Qualified across the -40 to +85C temperature range, the AAT2848 is available in a Pb-free, 20-pin TQFN package.
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