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MSP430L092: How using solar cells to 'L092

Part Number: MSP430L092

Hi Johann Zipperer,

From your reply on Sep 2, 2019, we know that many applications use two solar cells in series to run 'L092, but I use the 1,5V solar call used by Japanese Comix electronic calculator, but still find it can't run, and the LED keeps flashing. Is there any requirement for solar cells? Can you tell me the model or requirement for solar cells. 

Regards,

Ruan

  • Hello,

    Thanks for your posting.

    We will have expert looking into this for you.

    Thanks,

    Yiding

  • Hello Ruan,

    Last time we calculated that the energy source need to be able to drive ~13mA safely...

    I just checked for a solar cell on one of the common distributors and found a XOB17 from IXYS (it could be any other manufacturer as well; this one was just the first I clicked).

    The data sheet says I@Pmpp=39mA ; V@Pmpp=0.51V ; Vopen=0.63V  Size 22mm x 7mm.

    Two of those in series should do the job. Pmpp usually means bright daylight outside; A safety factor of three shall allow that in moderate light conditions it still operates. 

    Now any other manufacturer's cell should do the job as well. Important here is the low inner impedance. Here it translates into size.

    I expect two cells of a similar size 22x7mm each of a modern high efficiency type solar cell would to do.

    Older cells were not that efficient, and aged old ones are even worse. To be on the safe side triple the size again.

    Johann

  • Hi Johann,

    Thanks for all your help.

    I didn't find the solar cell you recommended. I bought some others and tested them. I'm afraid that the current of your recommened cell is not enough, but it can work well with a larger current cell

    .However, there's still a problem. the starting voltage needs to be high, close to 1.4V. After starting, reduce the light, and it can work until the output voltage close to 1V, which will not be affected by the V(BOR_IT+)?

    Ruan