LED Driver Manages SuperCapacitor-Based Photoflash
Addressing the expanding need for high-intensity LED flash capability, the CAT3224 Solid-State Lighitng Driver (SSLD) is capable of sourcing up to 4 A for photoflash and up to 400 mA of torch-mode current as well as the charging function for dual-cell supercapacitors. Functions such as charging, flash, and torch are activated via a parallel logic interface, with the operating current of each mode programmed by three external resistors. The SSLD 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. The 16-lead TQFN-packaged SSLD includes features such as thermal shutdown, overvoltage protection, and protection against external resistor programming faults.