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3rd May 09
LED drivers accustomed to supercapacitors
Power semiconductor device vendors are offering LED drivers
specifically designed for supercapacitors. Supercapacitors,
which are also called ultracapacitors can store large quantity
of electrical energy with some physical and mechanical advantages
over batteries.
LED flash drivers, which need high level of power for short
duration, are going for supercapacitor/ultracapacitor as
power source. The supercapacitor manufacturer CAP-XX has
named few latest led drivers supporting supercapacitor based
flash. They include AnalogicTech's AAT1282, and ON Semiconductor's
CAT3224 and yet-to-be-released NCP5680 supercapacitor-optimized
LED flash drivers.The LED flash driver reference designs
are available from Seoul Semiconductor and ON Semiconductor.
LED driver with supercapacitor can drive high-current white
LEDs (WLEDs) by occupying far lesser space in comparison
to outdated xenon flash. These LED flash drivers integrate
all circuitry required to charge the supercapacitor, manage
in-rush current and control LED current.
White LED based flash generate enough light to capture clear
images in digital cameras, but need up to 400% more power
than a battery can provide. To support the battery, a thin
supercapacitor can drive the LED flash to full intensity
while also handling other peak-power needs - zoom, auto-focus,
audio, video, wireless transmissions, GPS readings and RF
amplification - without compromising slimline design.
BriteFlash from CAP-XX combines an LED flash driver IC,
supercapacitor, battery and WLEDs. The flash driver's boost
converter charges the supercapacitor to 5.5V, which then
delivers high-peak current to drive the LED flash. The battery
only supplies average power, and recharges the supercapacitor
between flashes.
There is a whitepaper available for designers to learn more
on this article subject, it can be downloaded from http://www.cap-xx.com/resources/pres_wp/pres_wp.htm#wp
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