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bs2e power source — Parallax Forums

bs2e power source

TobiasTobias Posts: 95
edited 2007-07-29 05:27 in BASIC Stamp
I put the bs2e in the same socket where I had the bs2 with volts for power, am I going to damage the bs2e with a 12 volt power source?
Toby

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2007-07-29 05:24
    The regulator on the BS2e is capable of handling 12V. With all of the Stamps (including the BS2) the real issue is the power dissipation. The actual processor needs 5V and anything above that is dissipated as heat. The regulator is capable of supplying about 150ma of which about 1/3 is needed by the Stamp's processor. Whatever you attach to the I/O pins will also draw current. If you're running the whole thing at 12V and maximum current, you'll need to dissipate 7V x 150ma = 1W+. That's a lot of heat for a regulator with no real heatsink other than a little bit of copper on a thin printed circuit board. The regulator will overheat and it protects itself by shutting down.

    The bottom line is that you won't damage the Stamp, but it may not work for long if there's much in the way of current drawn from the Stamp for I/O. That's why Parallax recommends using no more than 9V to power the Stamps, preferably 7.5V - there's much less power dissipation.
  • OzStampOzStamp Posts: 377
    edited 2007-07-29 05:27
    Hi Toby.
    12VDC is fine but it is the max..
    The onboard Vreg being a LTC1121 can take higher voltages .
    Be care full with the max current you take from the VDD pin.. 5V generated on the BS2e
    as this can only really supply about 50mA .. ( it is all to do with total watts generated.)
    The LTC1121 has no heatsink so it will get hot very quickly if driven too hard..

    Cheer
    Ronald Nollet Australia
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