Power by Linear™ / Analog Devices' LTC4041 is a complete supercapacitor backup system for 2.9 V to 5.5 V supply rails. The device contains a high current step-down DC/DC converter to charge a single supercapacitor or two supercapacitors in series. When input power is unavailable, the step-down regulator operates in reverse as a step-up regulator to back up the system output from the supercapacitor(s).

The LTC4041's adjustable input current limit function reduces charge current to protect the input supply from overload while an external disconnect switch isolates the input supply during backup. When the input supply drops below the adjustable PFI threshold, the 2.5 A boost regulator delivers power from the supercapacitor to the system output.

An optional input overvoltage protection (OVP) circuit protects the LTC4041 from high voltage damage at the V_IN pin. An internal supercapacitor balancing circuit maintains equal voltages across each supercapacitor and limits the maximum voltage of each supercapacitor to a pre-determined value. The LTC4041 is ideal for power meters and industrial alarms.