The LTC3355 has all the functions needed to provide seamless charging of a supercapacitor (or other storage element), including the monitoring of VIN, VOUT and VCAP and automatic switchover to backup power, says Linear Technology. It has a main buck regulator with a built-in boost converter for temporary backup, or ride-through, of VOUT during a sudden loss of VIN power from a single supercapacitor energy source. The non synchronous constant frequency current mode monolithic 1A buck switching regulator provides a 2.7 to 5V regulated output voltage from an input supply up to 20V. This make it suitable for ride-through, or data backup supplies commonly used in power meters, industrial alarms and solid state drives. A thermal regulation loop maximises charge current while limiting the die temperature to 110°C. When the VIN supply drops below the programmable power-fail comparator input threshold, the device’s constant frequency non synchronous current mode 5A boost switching regulator delivers power from the supercapacitor to VOUT. Backup power can be delivered to VOUT with capacitor voltages down to 0.5V. Boost, charger and VIN current limits are programmable. Other features include a VIN power fail indicator, VCAP power good indicator, and VOUT power-on reset (POR) output. It is supplied in a thermally enhanced 20-lead, low-profile 4x4x0.75mm QFN package and operates over -40 to 125°C.

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