Olimex Support Forum

Others => UEXT => Topic started by: Patd93 on November 19, 2014, 12:52:50 PM

Title: RTC module with super capacitor
Post by: Patd93 on November 19, 2014, 12:52:50 PM
I am currently working on a project which requires an RTC module to be run off a super capacitor rather than a battery for the olimex board. Is their a module out their on the market that would be suitable? Or could the RTC module provided by olimex be modified to include super capacitor. If yes, how?
Title: Re: RTC module with super capacitor
Post by: Gerrit on November 19, 2014, 08:11:41 PM
Looking at the schematic

https://www.olimex.com/Products/Modules/Time/MOD-RTC/resources/MOD-RTC-REV-A-SCHEMATIC.pdf

I would say replace the battery with your capacitor, and put a resistor in series with a low drop diode between the plus from the capacitor and pen 1 from UEXT connector to limit the current for loading, maybe 27 ohm would be a good value