7 Dec 2011

Micropower generation/power harvesting

Linear Technology lists the LTC3108, an Ultralow Voltage Step-Up Converter and Power Manager than runs with an input of just 20mV producing a 5V output to power things such as low power wireless devices and processors. Surely there must be an application for such a device in ultra-QRP portable equipment? Imagine, where can you find 20-500mV of noise from? 50Hz crud in the ground, a thermo electric sensor, solar cells etc. I wonder who will be the first person to make a QRPp uW beacon powered using the 50/60Hz buzz available between a couple of earth electrodes in the ground?


Anonymous said...

Hello Roger,
two years or so ago, I built a RF-powered µW beacon, that worked from up 10µW RF - which you'll
find many hours per day on a few
meters of wire.
Used a discrete DC/DC converter and collected and stored the energy in a 1000µF capacitor.
But even with the increased propagation we enjoy now, who
is going to chase a 10...100µW
beacon that is transmitting a
short burst ( CW/MS-Hell ) every
ten minutes or so ?!
The LT-3108 works fine with low voltage, but draws a lot of current, which will be hard to get from any rectifier, while it fits fine for peltier-elements.
For your idea of exploiting 50Hz hum something like the
'Joule Thief' circuit might be a better solution, mine worked from
200mV/10µA for a 1.8V output with an effeciency comparable to that of the LT-chip.
Good Luck!

Roger said...

Fascinating Peter. Do you have any schematics?

73s Roger G3XBM