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For an experimental thermo-electric generator (TEG), developed by a colleague for low-power energy harvesting, it is possible to achieve an output power of 400 uW at the maximum power point. The voltage is 20 mV and the current is 20 mA.

This voltage needs to be switched up to at least 1.2 V, preferably 3.3 V.

  1. How would you choose to proceed to switch up such a low voltage, also considering a need for maximum power-point tracking (could be simply current-limiting the input)?

  2. It might not be possible, but in that case, what would you consider the minimum voltage, and how would you answer question 1 with that minimum voltage?

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    \$\begingroup\$ Research completed energy harvesting controller chips. Consider Linear Technology products, since I think they have something for this sort of application. \$\endgroup\$ Jun 21, 2016 at 15:40
  • \$\begingroup\$ What device do you need to power at 3.3V or 1.2V? \$\endgroup\$
    – MathieuL
    Jun 21, 2016 at 15:44
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    \$\begingroup\$ What Mr 2943160 said - LT and some others have ICs that accept inputs at that leve. They form an oscillator with a high ratio stepup transformer that uses the low voltage DC to produce LV AC which is stepped up by the transformer. Such arrangements will have low efficiencies best case and very low efficiencies unless you are a master of the dark arts OR use ICs from eg LT (who ARE masters of the dark arts). \$\endgroup\$
    – Russell McMahon
    Jun 21, 2016 at 16:58

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The low voltage isn't a huge problem in and of itself, there are ICs specifically designed for building boost converters for energy harvesting which can work down to 20mV e.g. Linear Technology 3108. This chip also acts as a power manager, which could be useful.

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