Linear has buck-boost supercapacitor for fast charging

The LTC3128 features an average input current limit that can be programmed up to 3A with +/-2% accuracy, preventing power source overload while minimising capacitor recharge time. Active charge balancing eliminates dissipative external ballast resistors, ensuring balanced operation and charging with mismatched capacitors, and less frequent recharge cycles. A programmable maximum capacitor voltage clamp actively monitors and enforces the voltage across each capacitor in the series stack, ensuring reliable operation as capacitors age and develop mismatched capacities. The low noise buck-boost topology allows the output supercapacitor to be charged whether above or below the input. The low-RDS(on), low gate charge synchronous switches provide high efficiency conversion to minimise the charging time of storage elements. The LTC3128's input current limit and maximum capacitor voltage are each programmed using a single resistor. Average input current is accurately controlled over a 0.5 to 3A programming range, and the individual maximum capacitor voltage can be set from 1.6 to 3.0V. Other features include <1µA quiescent current from VOUT in Burst Mode operation, accurate power good and power failure indicators and thermal overload protection.