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XBee - Need efficient way to regulate input voltage - 3.3v Power supply — Parallax Forums

XBee - Need efficient way to regulate input voltage - 3.3v Power supply

squarejsquarej Posts: 3
edited 2013-07-19 12:30 in General Discussion
I am struggling to find a highly efficient power source for my XBee Pro 900 Digimesh. They have incredible low sleep drains but supplying them with power going through a regulator still kills the battery even with a "really" efficient one like a Dimension Engineering 3.3v - uses 15ma at no load. So would this work - The XBee is powered by 2 alkaline batteries during sleep, when it wakes up pin DI-9 (sleep indicator) powers a transistor or relay that cuts power from the alkalines and turns on a larger lithium battery which goes through a 3.3v regulator to power the XBee and MCU just while its awake. When it goes to sleep the alkalines are put back online. I assume I would need a capacitor to provide power during the switch over too. Is there an easier way and i'm just overthinking this or is this a reasonable solution to use the least power possible? I haven't tried using just a single cell LiPo connected directly to the XBee, I wasn't brave enough to test the XBee max V input. Thank you for any help or links you can provide.

Comments

  • Tracy AllenTracy Allen Posts: 6,664
    edited 2013-07-15 08:00
    A good micropower low-dropout regulator for this is the MCP1703. Its quiescent current is 2µA (micro!), and it can deliver the 250mA @ 3.3V needed by the XBee pro from an input supply as low as 4V. It is a linear regulator with a pmosfet pass transistor.

    Oh, and welcome to the forums!
  • squarejsquarej Posts: 3
    edited 2013-07-15 17:55
    I just ordered several. Thank you for the fast reply!
  • squarejsquarej Posts: 3
    edited 2013-07-19 12:30
    This worked fabulously, appreciate the guidance.
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