V-Harvester board eliminates batteries in IoT apps

Maximizing IoT node efficiency by helping to replace regular batteries with a rechargeable photovoltaic (PV) energy-harvesting backup solution, the board is an HVC system backup demonstration circuit that enables developers to extend overall product life expectancy by implementing a longer, more sustainable maintenance-free, energy supply source for use in a variety of host system applications.

The Vishay board is an advanced stand-alone board charged using two default TEMD5080X01 micro PV cells or micro USB. The evaluation board is equipped with a 4 F / 4.2 V 196 HVC ENYCAP hybrid energy storage capacitor.

It has options to jumper to other storage capacitors on the backside (or a BATT_CN = battery connector). The HVC storage capacitor, like the 196 HVC ENYCAP found on the V-Harvester Board, is a more solid choice over less cycle-resistant rechargeable batteries and is much safer than lithium batteries.

Input power for the 196 HVC ENYCAP V-Harvester board goes into an e-peas low-power AEM10941 controller.

From there, it is stepped up to the supercapacitor voltage of 4.2 V. The onboard controller then converts the supply voltage to the target voltages using low dropout regulators (LDO) when there are power demands at the interface or through the ENLV and ENHV settings. Target voltages are set to 1.8 V (low voltage) and 2.5 V (high voltage) through a high ohmic resistor network. The lower series resistance of the system allows for higher currents or burst power support and generally facilitates higher power density.

An external PV cell can also be connected (and jumpered) if faster charging is required, or a jumper can be set to USB if light harvesting is not an option.

The Vishay 196 HVC ENYCAP V-Harvester board is available in a 64 mm × 69 mm footprint and includes product specifications (for the V-Harvester Board and 196 HVC ENYCAP storage capacitor) and a set of jumpers.

The device has a higher permissible operating temperature over non-HVC systems of -20°C to 85°C, and its target energy-harvesting applications include automotive, avionics, military, consumer, industrial, medical, and telecommunications.