Getting started with the RECOM Energy Harvesting Module

Oct 15, 2021
Getting started with the RECOM Energy Harvesting Module Blog Post Image
One of the main challenges in designing a successful energy-harvesting system is simply getting started. At the beginning, there are often too many unknowns to contend with and it can be overwhelming. Which energy source to use – photovoltaic, thermoelectric generator, electric field, flow-based or vibrational? How big should my storage element be? Should I use a supercapacitor or a rechargeable battery? What about energy security - do I need a back-up battery or will I scavenge enough energy during the day to keep on running through the night? And these are just the external aspects – what about optimization, choice and supply chain management of the electronic components in the harvester itself such as inductors, resistors and capacitors needed on my PCB to make a fully functioning energy harvesting system?
Pre-built modules speed up time-to-market

To help with this make-or-break decision making, RECOM has developed a pre-built, pre-tested energy harvesting module and an evaluation board based on the AEM10941 harvester IC.



The REH-3.31.8 module is a complete energy harvesting power supply, requiring just an energy source and a storage element to go. This frees up the design engineer’s valuable time to focus on the more important decisions such as finding the optimal solar cell for the light conditions available, to fine tune the resonant frequency of the vibrational generator or to experiment with the size of supercapacitor or Li-Ion battery needed to supply the load reliably 24/7.
To make this process even easier, RECOM also manufactures the REH-3.31.8-EVM-1 evaluation board with push-in wire connections for the energy source, storage element and the 3.3V and 1.8V output voltages. The evaluation board also contains pads for a CR2032 battery holder if an on-board back-up primary cell battery is needed. With the REH-3.31.8-EVM-1, it is possible to configure all of the features of the REH-3.31.8 module such as selection of the type of the storage element (rechargeable battery or supercapacitor), set the backup battery switch-over threshold voltage and to independently enable either or both outputs. All input and output signals of the module are easily accessible for test probes.

5 benefits of using the RECOM module:

  1. Ready-to-go. The REH-3.31.8 is a pre-tested 12.2mm x 12.2mm x 3.75mm SMD module with solder pads on the bottom and a metal case. No other external components are needed apart from the source and storage element to make a fully functioning energy harvester.
  2. Simple assembly. The large grid array (LGA) pads allow easy, reliable soldering onto a low-cost main PCB which can be single or double-sided. The metal case makes handling and using the pick-and-place machine uncomplicated and there is only one part in your BoM.
  3. Fast time-to-market. Get your energy harvesting design up and running from Day 1. From prototyping to mass-production runs, our European distribution hub and express delivery makes sure that you can scale up your production quickly.
  4. Easy experimentation. The REH-3.31.8-EVM-1 evaluation board allows experimentation with different energy sources or storage element manufacturers to select the optimal components fine-tuned for the individual needs of your application.
  5. Simple upgrade. If you later decide to upgrade to increase the amount of harvested energy, then the push-in connectors permit swapping over to a more effective energy harvester or larger storage element in seconds. Once everything is functioning correctly, then production can continue using the new configuration, with confidence that the operating specifications will not change.


Technical specifications of the REH3.31.8 and REH-3.31.8-EVM-1

The REH-3.31.8 is dual output energy harvester module designed primarily for photo voltaic (PV) cells, but capable of running from other low voltage DC supplies delivering 50mV or more. This unique and compact (12.19 x 12.19 mm) module contains all the circuitry required to run an energy harvesting system, including a Maximum Power Point (MPP) tracking function for the PV cell.
The user needs only to add the storage element (user selectable rechargeable battery or super capacitor) and connect the power source to make it operational. Two short-circuit protected fixed voltage regulated outputs (1.8V@20mA and 3.3V@80mA) can be individually enabled/disabled. An imminent shutdown signal warns the application that there is not sufficient energy being harvested to maintain the output voltage and the module is about to power down.



The REH-3.31.8-EVM-1 allows a quick and easy evaluation of the REH-3.31.8 energy harvesting module. It contains all the necessary easy-plug-in connectors to connect the energy source, energy storage element, twin output voltages and an external backup battery. The PCB footprint includes pads for a space-saving CR2032 battery holder to serve as an on-board backup battery, if required.

If a primary cell back-up battery (1.5V to 3V) is fitted, the REH-Module will automatically switch over to the back-up supply if the energy harvesting input fails to maintain an uninterrupted output.



How to purchase

Both the REH-3.31.8 module and the REH-3.31.8-EVM-1 evaluation board are available from RECOM headquarters in Austria or from one of our business development managers based in the UK, Germany, Italy, Russia, USA or Japan.
Applications
  Series
1 DC/DC, Dual Output REH-3.31.8-EVM-1 Series
  • Evaluation platform for REH-3.31.8 energy harvester module
  • Supports rechargeable Li-Ion battery or supercapacitor as energy storage
  • Backup coin cell battery holder footprint and input for uninterruptable operation
  • Easy setup and evaluation