MAXREFDES1215: Supercapacitor-based Energy Harvester Using the MAX17220

Supercapacitors are increasingly being used in a number of applications in electric vehicles, transportation equipment, industrial machinery and utility grids. In the MAXREFDES1215, a supercapacitor-based energy harvester is demonstrated using the MAX17220. The circuit uses a supercapacitor to provide backup energy. The first stage of the circuit charges a supercapacitor, and the second stage of the circuit regulates the voltage from the supercapacitor to supply various sensors with a steady output voltage. In this system, the MAX17220 is used for regulating the output voltage from the supercapacitor.

The MAX17220 is an ultra-low quiescent current boost (step-up) DC-DC converter with a 225mA peak inductor current limit and True Shutdown^™. True Shutdown disconnects the output from the input with no forward or reverse current. The output voltage is selectable using a single standard 1% resistor. MAX17220 has post-startup enable transient protection (ETP), allowing the output to remain regulated for input voltages down to 400mV, depending on load current. The MAX17220 offers ultra-low quiescent current, small total solution size, and high efficiency throughout the entire load range. These features make this product especially suitable for use in battery-powered medical equipment, low-power wireless communication products, primary-cell and secondary-cell portable systems, and tiny, low-power IoT sensors.