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3.3V to 5V — Parallax Forums

3.3V to 5V

bboy8012bboy8012 Posts: 153
edited 2008-07-19 23:36 in Propeller 1
How would I boost the 3.3V supply to 5V? I am trying to interface the Parallax GPS but do not know which component to use. I thought about a MOSFET but I just want to get experts point of views. Thanks

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2007-12-14 22:35
    Do a web search for "boost regulator" and you'll find a whole variety of different types of devices that will take a voltage like 3.3V and "boost" it to a regulated 5V. Figure out how much current you will need at 5V and choose a device based partly on whether it will furnish that amount of current. Often the manufacturer will have an evaluation board available at a reasonable cost.

    Here's one I found right away: www.national.com/pf/LM/LM2750.html

    Post Edited (Mike Green) : 12/14/2007 10:40:47 PM GMT
  • RaymanRayman Posts: 14,820
    edited 2007-12-14 23:10
    I like the·LM3351 (http://www.national.com/mpf/LM/LM3351.html) Switched Cap Voltage Converters...

    These can convert from 5 to 3.3 V or from 3.3 to 5 V with 95% efficiency!· Just needs 4 external caps to work...

    Only bad things are:

    1.· Relatively low output current rating (50 mA)
    2.· Extremely small size (I went through 4 before I got one soldered into a DIP socket...)
  • David BDavid B Posts: 592
    edited 2007-12-15 00:19
    Do you already have a supply of just 3.3V? Some prototype or experimenter boards provide regulated 5 volts as well as the 3.3V propeller supply, so if you don't already have your hardware, getting a board like that might be an easy way to get your 5V power.
  • Dennis FerronDennis Ferron Posts: 480
    edited 2007-12-15 06:08
    Or are you really asking how to boost (i.e. interface) the data lines to 5 volts?
  • Mike GreenMike Green Posts: 23,101
    edited 2007-12-15 06:37
    If you want to interface the 3.3V logic of the Propeller to the 5V logic of other stuff, there's a whole "sticky" thread on the subject (the very first one): http://forums.parallax.com/showthread.php?p=667581
  • jeffjohnvoljeffjohnvol Posts: 197
    edited 2008-07-19 19:54
    Sparkfun.com has a breakout board that might be of use for transporting signals in each direction.· It handles 2 inputs and 2 outputs.· Looks like you would have to have each input/output hardset (can't change directions).

    They are under $2 per board with discounts for 10 or more.· (I'm not affiliated with this company).

    http://www.sparkfun.com/commerce/product_info.php?products_id=8745#



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  • Erik FriesenErik Friesen Posts: 1,071
    edited 2008-07-19 23:36
    I think the pmb-238? gps module that parallax is using is 3.3v compatible. I'm not sure if the sx chip is though. You could run the raw data and translate it yourself with fullduplexserial and a mod of the sx firmware.
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