Energy harvesting module steps up low voltages
In general, energy sources for harvesting applications are not only low power — they are at low voltages. Piezoelectric devices are the exception, but thermoelectric generators (TEGs), inductive coils, and photovoltaic cells tend to have output voltages that range below half a volt. Most electronic circuits, including power conversion circuits, require voltages in the 2+ voltage range. So before an application can convert and regulate harvested energy from TEGs, coils, and PVs it must first boost the voltage up, and as efficiently as possible: When you’re working with microwatts to begin with, you can’t afford to throw much away in your boost conversion.
Advanced Linear Devices has introduced the EH4200 series of MicroPowerStep-up Low-Voltage Booster Modules to perform this step-up power conversion function. Two micropower step-up booster models ALD EH4205/4295, each with different source input impedance matching characteristics are currently available. The ALD EH4205 features a nominal input impedance of 50 ohms while the ALD EH4295 features an input impedance of 950 ohms: Lower power applications will use the higher impedance version while a higher power can use the power impedance version.
ALD MicroPower Step-up Low-Voltage Booster Modules are compatible and best suited for driving loads such as the ALD EH300/EH301/EH300A/EH301A Energy Harvesting Modules. The EH4205/4295 output can be directly connected to the input terminals of the Energy Harvesting Module using a standard two-wire cable. ALD booster modules can also be used, independently for trickle-charging batteries or super-caps, including situations where the energy generating input source is intermittent and not well controlled or regulated.
Both EH4205 and EH4295 are available for immediate delivery and can be ordered from DigiKey or Mouser Electronics. Small quantities are priced from $41.00 each. Evaluation kits and cable assemblies are also available.
Hugh Gibbons commented:
$41 for 125mW maximum useful output power comes to $328 per watt. I can think of an awful lot of power sources that are smaller, cheaper and more powerful than that.
The interesting thing about this technology is not that it works, but that somebody bothered with it at all.
Don Sauer commented:
Wonder how long it will take for the industry to wise up to what a energy harvesting resistor can do? Imagine a circuit that has the voltage to current relationship of a resistor which can be adjusted to any resistance value. The only difference is that instead of dissipating power, it translates any power a resistor would normally dissipate into DC power, with the efficiency of a DC to DC converter. In fact, it consists of simply using a simple DC to DC converter differently.
Andy T commented:
$41 will buy a LOT of coin cells. If your circuit takes microwatts, as an energy harvester would supply, the coin cells should last a few centuries more than you do.
John Smith commented:
While working on early lasers back in the 60s, I needed a good ground reference, so I drove some short rods into the ground around the hut that the laser was in, and found that I had quite a bit of AC and a standing DC difference between each ( identical ) rod.
You can actually get small but useful voltage from the current flowing through the ground.
rdelaplaza commented:
It will be great if you live next to a radio station transmitter site.
Otherwise the power density in the space is so low that makes it worthless for anything practical, unless we are talking VERY high frequency waves (= light: use solar panels)
the use of galena receivers getting airwaves power to drive headphones... Old, veeery old stuff.
Security Insider Blog commented:
Read the Hunt for Zero Point, then google scholar searxh "casimir effect". Filter by 2011, and you will find that many are researching harvesting zero point energy. NASA, DOE, not just the crazies in their garages anymore. This is the future of energy harvesting.
Meredith Poor commented:
Keyword search 'mudwatt'
foxdove commented:
I don't know where you got your info, but inductive coils certainly can be designed to produce outputs greater than 0.5 Volt as you state. Also gathering ambient EM is legal but limited to resonance issues, but the field is more or less viewed with humour unfortunately but most. I do research in the area of energy harvesting and see ambient EM as a upcoming useful methodology as well as novel inductive means.
D Soss commented:
Harvesting energy from ambient RF is unreliable and inconvenient. You need a resonant circuit in order to get a useful output. Fifty years ago, hobby magazines occasionally published articles on "stolen power" radios. These used power from a strong local station to power a receiver tuned to a weaker station. They had two tuning knobs: one for the power source station and one for the station you wanted to listen to.
WT commented:
I think the most reliable energy harvesting is to put a pickup coil near the utility high voltage pole .......
Meredith Poor commented:
Another low voltage source is a 'microbial fuel cell'. To make one, take the mud from the bottom of a pond and fill a small jar half full. Fill the top half with clear water. Put one graphite electrode in the mud, the other in the clear water. In about 2 weeks, bacteria will colonize the graphite in the mud and start donating electrons. The shortest way out is through the wiring. Power output for one cell is 1/10th of a watt and .5 volt. These can be put in series. This would make a great use of a booster module. It runs for about six weeks before one has to clean it out and start over.
R B Britton commented:
No word yet on the conversion efficiency?
As for ghost meters, we had a good one back in the 1800s; the electroscope comprising two strips of thin, flexible foil hanging adjacent in a Mason jar. So sensitive a cat could walk by on a dry day and set it off.
As for energy harvesting, I don't hear much about gathering electro-magnetic waves from space. In urban areas, there must be many watts available from powerful TV, FM, and AM stations. Is it not legal?
