Driver For Supercap-Based Camera LEDs Delivers 4 A

Jan 22, 2009 10:40 AM, MD&D News Staff

Targeting the need for a very high-intensity flash for high-megapixel cameras, the CAT3224 from On Semiconductor is the first 4-A supercapacitor LED flash driver, according to the company. The highly integrated device includes all the functions needed to accurately control LED flash charge/discharge, including power switches able to source up to 4 A and providing the charging function for dual-cell supercapacitors.

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The CAT3224 offers an easy-to-use solution with three fully independent operational modes (charging, flash, and torch) activated via a simple parallel logic interface. The operating current of each mode is easily programmed by three external resistors. In torch mode, it can source up to 400 mA. The company plans to introduce additional higher-power supercapacitor-based LED flash drives later this year.

The device incorporates a dual-mode 1x/2x charge pump, which charges the stacked supercapacitor to a nominal voltage of 5.4 V, while an active balance control circuit ensures that both capacitor cell voltages are matched during the charging cycle. In addition, the CAT3224 provides the user with a dedicated logic output to flag the completion of the supercapacitor charging sequence.

Housed in a space-saving, 16-lead TQFN 3- by 3- by 0.8-mm package, the CAT3224 features thermal shutdown, overvoltage protection, and protection against external resistor programming faults. The device also supports reverse output voltage for all conditions.

The CAT3224 supercapacitor LED driver costs $0.97 each in 10,000-piece quantities. Samples and evaluation boards are available now. Projected lead-time for production quantities is currently six to eight weeks after receipt of an order.