Shop OBEX P1 Docs P2 Docs Learn Events
Propeller Mini 5V Supply — Parallax Forums

Propeller Mini 5V Supply

RobertDyerRobertDyer Posts: 23
edited 2014-05-21 18:46 in Propeller 1
I want to use the Prop Mini Board in a new project where I already have 5V available and nothing higher. Can I connect my available 5V to pin 4 of the Mini Board, as a voltage input (for the 3.3V regulator), w/o damaging the 5V regulator? I looked at the datasheet for the LM2940 and I see that it is protected against reverse polarity connections, but I'm not sure it this gets me off the hook or not. My analog knowledge isn't good enough to look at the schematic of the chip (in the 2940 datasheet) to tell if connecting the output pin w/o connecting the input is a problem. Worst case I can pull the 5V regulator, but I'd like to leave the Mini Board intact so I could move it to another project in the future if needed. Thanks.


Also, the online schematic for the Mini Board appears to have a couple errors: The 5V regulator is labeled as an M24512 which I believe is a memory chip, and the 3.3V regulator is labeled as a 5V regulator.

Comments

  • JonnyMacJonnyMac Posts: 9,105
    edited 2014-05-21 18:06
    I spoke with Chris at Parallax a couple months ago about the same thing. He said it was okay (the regulator in an LM2940) and I didn't have an problems with it.
  • RobertDyerRobertDyer Posts: 23
    edited 2014-05-21 18:11
    PERFECT! Thanks.
  • David BetzDavid Betz Posts: 14,516
    edited 2014-05-21 18:46
    I've tried it and it seems to work fine.
Sign In or Register to comment.