ON Semi Debuts 4A, Single-Chip Driver For Supercapacitor-Based LED Camera Flash Applications
ON Semiconductor has introduced what it claims is the industry’s first 4A supercapacitor LED flash driver. The new CAT3224 addresses the emerging requirements for true high-intensity LED flash capability in high megapixel camera phones and standalone camera applications. The device is highly integrated with all the functions necessary to accurately control LED flash charge/discharge, including power switches capable of sourcing up to 4A, as well as providing the charging function for dual-cell supercapacitors. 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 and the operating current of each mode easily programmed by three external resistors. Additional higher power supercapacitor-based LED flash drives will be released later this quarter.
The supercapacitor discharges its power for peak-load functions and recharges continuously, even during the flash peaks. The CAT3224 LED driver controls the supercapacitor charge to create additional energy for the other high-peak current circuits. This supercapacitor LED driver design approach is said to enable true, high-intensity flash and more system functionality, while significantly extending battery life.
The high peak current benefits of supercapacitor technology, combined with the simple parallel logic interface of the CAT3224, also make the device suitable for industrial applications where LEDs are being used to replace xenon-based lighting.
"The CAT3224 supercapacitor LED driver provides an integrated, easy-to-use, cost-effective solution for high-intensity LED flash capability," said Scott Brown, Vice President of Marketing for the Catalyst Group of ON Semiconductor. "We believe this device, along with significant improvements in supercapacitor technology from companies such as CAP-XX Limited and the ever-increasing performance of white LEDs, will combine to make true high brightness LED flash viable for the first time in next-generation, high-megapixel camera phones and standalone cameras."
The CAT3224 supercapacitor LED driver supports three key functions: precise supercapacitor charging control, management of the current discharge into the LED flash, and constant current for LED torch mode. The CAT3224 sources up to 4A LED flash pulses and up to 400mA torch-mode current, with simple programming via external resistors on the analog control inputs. The device incorporates a dual-mode 1x/2x charge pump, which charges the stacked supercapacitor to a nominal voltage of 5.4V, 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.
Packaged in a space-saving, 16-lead TQFN 3 x 3 x 0.8mm package, the CAT3224 features thermal shutdown, overvoltage protection (OVP) and protection against external resistor programming faults. The device also supports reverse output voltage for all conditions.
Pricing for the CAT3224 supercapacitor LED driver is $0.97 USD per unit in 10,000 piece quantities. Samples and evaluation boards are available now. Projected lead-time for production quantities is currently 6 to 8 weeks ARO.
