High Current Supercapacitor Backup Controller and System Monitor

The LTC3350 is a backup power controller that can charge and monitor a series stack of one to four supercapacitors. The LTC3350’s synchronous step-down controller drives N‑channel MOSFETs for constant current/constant voltage charging with programmable input current limit. In addition, the step-down converter can run in reverse as a step-up converter to deliver power from the supercapacitor stack to the backup supply rail. Internal balancers eliminate the need for external balance resistors and each capacitor has a shunt regulator for overvoltage protection.

The LTC3350 monitors system voltages, currents, stack capacitance and stack ESR which can all be read over the I2C/SMBus. The dual ideal diode controller uses N-channel MOSFETs for low loss power paths from the input and supercapacitors to the backup system supply. The LTC3350 is available in a low profile 38-lead 5mm × 7mm × 0.75mm QFN surface mount package.

APPLICATIONS

* High Current 12V Ride-Through UPS

* Servers/Mass Storage/High Availability Systems

* High Efficiency Synchronous Step-Down CC/CV Charging of One to Four Series Supercapacitors

* Step-Up Mode in Backup Provides Greater Utilization of Stored Energy in Supercapacitors

* 14-Bit ADC for Monitoring System Voltages/Currents, Capacitance and ESR

* Active Overvoltage Protection Shunts

* Internal Active Balancers—No Balance Resistors