Photoflash Charger IC Extends Camera Battery Life September 2004 Issue Published Date: September 24, 2004
Producing a flyback conversion efficiency as high as 75%, the ZXSC440 photoflash charger IC increases the battery life of cameras and strobe equipment using Xenon flash tubes. The IC can charge an 80 µF capacitor to 300V in 3.5 seconds from a 3V supply. To conserve battery power, the IC uses negligible current while not charging—just 4.5 µA. A small amount of hysteresis on the voltage feedback pin shuts the device down as long as the capacitor remains fully charged. Interfacing to a microcontroller requires just two pins: a charge pin starts and stops photoflash charging and a ready pin indicates that the photoflash is fully charged and ready for shooting. An external resistor network configures the IC for different capacitor values. Overall charger efficiency depends on the choice of switching transistor on the drive output. The IC is housed in a low-profile MSOP8 package. Pricing is $0.54 each/10,000. ZETEX INC., Hauppauge, NY. (631) 360-2222.
