Features

• 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
• V_IN: 4.5V to 35V, V_CAP(n): Up to 5V per Capacitor, Charge/Backup Current: 10+A
• Programmable Input Current Limit Prioritizes System Load Over Capacitor Charge Current
• Dual Ideal Diode PowerPath™ Controller
• All N-FET Charger Controller and PowerPath Controller
• Compact 38-Lead 5mm × 7mm QFN Package

Typical Application

Description

The LTC®3350 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.