A8439

www.DataSheet4U.com A8439 Photoflash Capacitor Charger with IGBT Driver and Refresh Features and Benefits ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ Power with 1 Li+ or 2 Alkaline/NiMH/NiCAD batteries Adjustable output voltage Auto-refresh >75% efficiency Eight-level, digitally-programmable current limit Charge complete indication Integrated IGBT driver with trigger No primary-side Schottky diode needed Low-profile package (0.75 mm nominal height) Description The A8439 is a highly integrated IC that charges photoflash capacitors for digital and film cameras. An integrated MOSFET switch drives the transformer in a flyback topology. It also features an integrated IGBT driver that facilitates the flash discharge function and saves board space. The CHARGE pin enables the A8439 and starts the charging of the output capacitor. When the designated output voltage is reached, the A8439 stops the charging until the CHARGE pin is toggled again, or when output voltage falls below 90% of the designated value. Pulling the CHARGE pin low stops the charging. The D ¯ ¯O ¯ ¯N ¯ ¯E ¯ ¯ pin is an open-drain indicator of when the designated output voltage is reached. The peak current limit can be adjusted to eight different levels between 270 mA and 1.4 A, by clocking the CHARGE pin. This allows the user to operate the flash even at low battery voltages. The A8439 can be used with two Alkaline/NiMH/NiCAD or one single-cell Li+ battery connected to the transformer primary. Connect the VIN pin to a 3.0 to 5.5 V supply, ...