Photoflash Charger with Adjustable Input Current and IGBT Driver

The LT3585 series are highly integrated ICs designed to charge photoflash capacitors in digital and film cameras. A new control technique allows for the use of extremely small transformers. Each part contains an on-chip high voltage NPN power switch. Output voltage detection is completely contained within the part, eliminating the need for any discrete zener diodes or resistors. The output voltage can be adjusted by simply changing the turns ratio of the transformer.

The CHRG/IADJ pin gives full control of the part to the user. Driving CHRG/IADJ low puts the part in low power shutdown. The CHRG/IADJ pin can also be used to reduce the input current of the charger, useful in extending battery life. The DONE pin indicates when the part has completed charging.

The LT3585 series of parts are housed in tiny 3mm × 2mm DFN packages.

Applications

* Digital/Film Camera Flash

* PDA/Cell Phone Flash

* Emergency Strobe

* Adjustable Input Current

* Integrated IGBT Driver

* No Output Voltage Divider Needed

* Uses Small Transformers: 5.8mm × 5.8mm × 3mm

* Fast Photoflash Charge Times

* Charges Any Size Photoflash Capacitor

* Supports Operation from Single Li-Ion Cell, Two AA

* Cells or any Supply from 1.5V Up to 16V

* Small 10-Lead (3mm × 2mm) DFN Package