LTC3108 for small scale electromagnetic generator

Hello, I'm building a small scale vibration energy harvester made up of coils and magnets (electromagnetic generator). The generator currently produces an output in the range of 0-300mV AC. I was wondering whether the LTC3108 will be suitable for this application for the purpose of boosting the voltage up to a usable amount to charge a supercapacitor or a battery.

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  • 0
    •  Analog Employees 
    on Feb 8, 2019 8:35 PM

    Hi,

    You should be able to harvest energy using LTC3108 from an input source of 0-300mV. If the source is AC the LTC3109 could also be an option as it can work with either polarity. However, since your source is a generator, you have to keep in mind the source resistance due to coils which might be quite high wrt to the input resistance of LTC3108 (it is around 2-3 ohms). The source resistance should be matched or can be lower than the input resistance of the LTC3108 for maximum output power.   

    The datasheets have few typical application examples on battery charging  and supercap charging which you might refer.

    Thanks

  • Another question I have. What is the significance of a transformer at the input pins of the LTC3109. Would that be necessary or can I just connect my low voltage AC generator directly to it without any transformers?

    Many thanks

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  • 0
    •  Analog Employees 
    on Feb 21, 2019 5:26 PM in reply to marios95b

    Hi,

    The transformer is needed to boost the input voltage and together with the capacitor its forms a self resonating converter.  You can use the part without transformer if the input voltage is high and in that case there will be no boosting. (Page 20 in datasheet of LTC3108-1 has few applications without the transformer). But for Vin=0-300mV AC, a transformer is required. There are few recommended transformers mentioned in the datasheet.     

    Thanks