
Allegro MicroSystems
Description
The A8426 is a highly integrated IC that rapidly charges photoflash capacitors for SLR cameras, digital cameras, and camcorders with integrated digital cameras. A flexible IGBT driver is integrated to save board space.
The A8426 integrates a 3.2 A-capable, 55 V-rated DMOS switch that drives the transformer in flyback configuration, allowing optimized design with tight coupling and high efficiency. The peak switch current is user-adjustable between 1 and 3.2 A, using a resistor to ground. A proprietary control scheme optimizes the capacitor charging time. Low quiescent current and low-power Standby mode current further improve system efficiency and extend battery life.
FEATUREs and Benefits
▪ Wide battery voltage range: 1.5 to 11 V
▪ Integrated 55 V DMOS switch with 3.2 A current capability
▪ User-adjustable peak current limit, from 1 to 3.2 A
▪ Secondary-side voltage sensing for easily-adjustable
output voltage
▪ >75% efficiency
▪ Fast charging time
▪ Charge complete indication
▪ Flexible, high current IGBT driver
▫ Independent IGBT driver supply
▫ Separate sink and source pins with 6 Ω pull-up and
20 Ω pull-down
▫ Interlocked trigger pins improve noise immunity
▪ No primary-side Schottky diode needed
APPLICATIONs include:
▪ SLR camera flash
▪ Digital camcorder/DSC combo flash
▪ 2 Li+ input strobe