A8835: Photoflash Capacitor Charger with Programmable Current Limit and IGBT Driver

Description

These parts are discontinued. Samples are no longer available. For new customers or new applications, please contact Allegro. Date of status change: March 10, 2014.

The A8835 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 A8835 and starts the charging of the output capacitor. When the designated output voltage is reached, the A8835 stops the charging until the CHARGE pin is toggled again. The DONE 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 550 mA and 1.75 A, by clocking the CHARGE pin. This allows the user to operate the flash even at low battery voltages.

The A8835 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, which can be either the system rail or the Li+ battery, if used.

Applications include:

  • Digital camera flash
  • Film camera flash
  • Cell phone flash
  • Emergency strobe lights

The A8835 is available in a very low profile (0.75 mm) 10-contact 3 mm × 3 mm MLP/TDFN package, making it ideal for space-constrained applications. It is lead (Pb) free, with 100% matte-tin leadframe plating.

Top Features

  • Eight-level, digitally-programmable current limits from 550 mA to 1.75 A
  • Voltage sensing feedback before output diode for low leakage
  • No external pull-down resistors needed
  • Power with 1 Li+ or 2 Alkaline/NiMH/NiCAD batteries
  • Low quiescent current draw (1 µA max in shutdown mode)
  • Zero-voltage switching for lower loss
  • Adjustable output voltage
  • Integrated IGBT driver with trigger
  • Charge complete indication >75% efficiency
  • Low-profile (0.75 mm high) 3 mm × 3 mm MLP/TDFN 10-contact package

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Compliant
Part Composition /
RoHS Data
Comments Samples Check Stock
A8835EEJTR-T 10-lead DFN -40°C to 85°C Yes View Data Discontinued Contact your
local sales rep
Check
Distributor Stock

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.

Packaging

The A8835 is available in a very low profile (0.75 mm) 10-contact 3 mm × 3 mm MLP/TDFN package (suffix EJ), making it ideal for space-constrained applications. It is lead (Pb) free, with 100% matte-tin leadframe plating.

EJ TDFN with exposed pad 10 contact