February 18, 2014 – Linear Technology Korea (CEO Hong Sa-gwak) announced the launch of the LTC3128, a buck-boost supercapacitor charger with high-efficiency input current limiting functionality.

This product provides active charge balancing for one or two series-connected supercapacitors. The LTC3128 features average input current limiting capability programmable up to 3A with +/-2% accuracy, minimizing capacitor recharge time while preventing power source overload. High-efficiency active charge balancing eliminates consumptive external ballast resistors, ensuring balanced operation and charging of unbalanced capacitors while reducing recharge cycles.

The programmable maximum capacitor voltage clamp automatically monitors and supervises voltage across each capacitor in the series-connected stack, ensuring reliable operation when capacitors age and capacity imbalance occurs. Through a low-noise buck-boost topology, the output supercapacitor can be charged regardless of whether the input voltage is low or high. Low RDS(on) and low gate charge synchronous switches provide high-efficiency conversion and minimize charge time of storage elements.

With these features integrated, the LTC3128 is ideal for safely charging and protecting high-capacity capacitors in backup power applications.

The input current limit and maximum capacitor voltage of the LTC3128 can each be programmed using a single resistor. Average input current is precisely controlled in the 0.5A to 3A programming range, and individual capacitor maximum voltage can be set from 1.6V to 3.0V.

Other features of the LTC3128 include standby current less than 1μA at VOUT during Burst Mode® operation, accurate power good, power fault indicator, and thermal overload protection.

The LTC3128 is available in a compact 4mm x 5mm QFN and 24-pin TSSOP package with excellent thermal performance, and both packages operate over the -40°C to 125°C range.

Photo caption: 3A buck-boost supercap charger with precise 2% input current limiting function