Tutorial and Experiments on Energy Harvesting ICs

In this episode Shahriar investigates some state-of-the-art energy harvesting ICs from Linear Technology. The LTC3105 is a highly efficient 400mA Step-Up DC/DC Converter with Maximum Power Point Control and 250mV Start-Up. After exploring the IC’s internal block diagram, the evaluation board for this energy harvesting chip is presented. Various experiments, including the calculation of efficiency, maximum power delivery, start-up behavior and MPPC are presented. As a last experiment, a two stage energy harvesting setup using a solar panel and a super-capacitor capable of charging an iPhone is demonstrated.

The second IC of interest is the LTC3109 which is an Auto-Polarity, Ultralow Voltage Step-Up Converter and Power Manager Energy Harvesting chip. The block diagram and the evaluation board of this IC is presented. The ultra-low voltage capability of the circuit is demonstrated through the use of a Peltier cooler thermo-electric component to generate a 5V output voltage. As a final experiment, several ice cubes are used in conjunction with the thermo-electric generator in order to harvest enough energy to charge an iPhone for 30 seconds.


  1. Sam says:

    Where did you buy the evaluation boards from?

  2. Sam says:

    Where did you buy the evaluation forms from?

  3. Viswanath says:


    Great job explaining the circuit :).. Im trying to build a similar one for lemon batteries. On building the circuit with regular component (not smd), the startup is happening only at 0.7 V. Do you have any idea why that is happening?

  4. Al says:

    Hi Shahriar – Very interesting and good descriptions. Is it necessary to have the supercapacitor and 2nd IC to power the phone (TEG–>IC 1 –> Supercap–>IC2–>USB Hub–> Phone)? Why not connect the output of the 1st IC directly to the phone (TEG–>IC 1 –> USB Hub –> Phone)?

  5. […] с электронного сайта The Signal Path выложили в сеть на всеобщее обозрение […]

  6. Mark says:

    Great video, thanks for taking the time to make it.

  7. wvdv2002 says:

    Thanks for the interesting video.
    Is it me, or does it look like the tantalum capacitor between the GND and Vin is connected with reverse polarity?

  8. […] devoted the lastest episode of The Signal Path to looking at energy harvesting chips. These parts are designed to gather energy from non-traditional sources as efficiently as possible. […]

  9. AA says:

    What is the switching frequency of this device? The noise was quite noticeable around the 27 minute marker.

  10. […] devoted the lastest episode of The Signal Path to looking at energy harvesting chips. These parts are designed to gather energy from non-traditional sources as efficiently as possible. […]

  11. Simon says:

    Very nice video thank you.

    I have always wanted to look into these energy harvesting modules I keep seeing them advertised at Mouser, Farnell, etc. They look very nice and you did a great job explaining.

    At first I thought they would be good to use on some of my projects as I have several sensors that gather data and only transmit very briefly. The only thing is in this sort of project where the microcontroller tics over on micro amps most of the time a well picked battery can last for years anyway and is probably easier and cheaper to use. But it is a nice idea to think you could leave some electronics to run autonomously (almost) indefinitely.

    I look foward to the next.

  12. Thank your for yet another great video.
    I’m currently working on a data logger that takes 4xAA rechargeable batteries that gives me 4.8V. From this the logger is able to run for 47 days taking light and temperature measurements every 30 seconds, giving me over 130.000 measurements.
    To achieve this battery is only powering the DS1337S+ real time clock between measurements.
    The data logger itself has a AMS1117 3.3V voltage regulator.
    So my question is, would I gain more run time if I added a LTC3105 between the battery pack and the data logger, or would it draw more current in sleep mode (ps. The RTC have to draw it’s power through the LTC3105 constantly 0.5uA)
    Geir Andersen

    • Shahriar says:

      You could take the 3.3V regular out of your setup and use the LTC3105 in its place. Remember that the advantage would be that you can discharge your batteries to a very low voltage of 0.3V while still getting 3.3V from the LTC3105. But you would not want to do that to a re-chargeable battery. However, for non-rechargeable batteries, getting every last drop of power out is a good thing.

      As for your second question about the sleep current, I would have to check how much input current is required to generate 0.5uA at 3.3V.

  13. Wilfred says:

    Thanks for the very interesting videos. I will continue to look forward the next one.

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