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Topic: Super capacitor power supply Zero (Read 154 times) previous topic - next topic

DCloud

Hi all,

I was wondering if it's possible to power the ATSAMD21G18 with a super capacitor.

I need this for a couple of hours and only if there's a black out, otherwise the samd is powered by a power

supply.

I thought that with a "black out detector"  :)  I could put the SAMD in a sleep mode until there's the black

out.

Hope I explained well, even if there are no details..  ;D

Thanks

westfw

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I was wondering if it's possible to power the ATSAMD21G18 with a super capacitor.
Sure.

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I need this for a couple of hours
There's a spreadsheet from PowerStor that says if you want to provide 10mA for an hour at 2.5V to 3.3V, you'll need about 100J, which should take about 50F worth of supercap..  (that's ... a lot.)  A battery would probably be a better choice (A CR2032 coin cell has about 2500J capacity.)
Supercaps are still pretty lousy compared to batteries; things that use supercaps geneally recognize power failures and immediately switch to some sort of low-current standby mode.  (A SAMD21 has a standby consumption of about 100uA.  At that rate, you'd only need about 0.5F to last an hour...)


DCloud

Hi westfw

thank you for your reply!

I wanted to use a supercap because I cannot use a battery. My idea was to the replace an external RTC ( powered with a supercap ) and use the internal RTC of the SAMD21G18.
But if it last only 1 hour, i think i won't replace the RTC.

Thanks again  :)

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