1. Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
    Dismiss Notice

Need help...12v to 14v dc converter

Discussion in 'Alternative Energy' started by dearu237, May 25, 2008.

  1. dearu237

    dearu237 New Member

    Joined:
    May 25, 2008
    Messages:
    2
    Likes:
    0
    I want to build a 12v to 14v converter with LM2577T-Adj but i found 12v to 16v scheme diagram, any one can help what part i should chance to...?
    in this scheme to make 12v to 14v output...?
     

    Attached Files:

  2. erosennin

    erosennin New Member

    Joined:
    Jul 15, 2006
    Messages:
    208
    Likes:
    2
    Location:
    Melbourne, Australia
    It's going to be more than one... Check the datasheet, it's relatively straight forward, just follow the formulas and don't skimp on the inductor.
    http://www.electro-tech-online.com/custompdfs/2008/05/LM1577.pdf


    If you wanted to be EXTREMELY el-cheapo, you can add 3 silicon diodes to the output to drop it by approximately 2.1V This however will vary with the current being drawn and isn't recommended. If you don't care about proper regulation, then this is okay, otherwise do it properly....
     
  3. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

    Joined:
    Jan 4, 2007
    Messages:
    21,220
    Likes:
    644
    Location:
    Ex Yorks' Hants UK

    hi,
    Reduce R1 [12k] to about 10.5K.
    This is the Vsamp feedback to the switcher.

    Look at the Vout formula [near the Vout terminal]

    Vout = 1.23 * [1 + 10.5/1] = 1.23 * 11.5 = 14.14Vout.........OK?
     
    Last edited: May 26, 2008
  4. dave

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    -
    Likes:
    0


     
  5. Hero999

    Hero999 Banned

    Joined:
    Apr 6, 2006
    Messages:
    14,902
    Likes:
    79
    Location:
    England

    Have you checked that the appliance designed to run from 14V won't run off 12V?

    The chances are you're wasting your time as you don't need a switching regulator.
     
    Last edited: May 26, 2008
  6. dearu237

    dearu237 New Member

    Joined:
    May 25, 2008
    Messages:
    2
    Likes:
    0

    thanks to remind me about the Vout formula....but i don't find the 10.5 resistor so use 22k and 2k and the result in the tester 14.3....
    thanks to every body for the help........... :D
     
  7. ste5442

    ste5442 New Member

    Joined:
    Jul 18, 2008
    Messages:
    25
    Likes:
    0
    Location:
    Cambridge UK
    How would you step-up from 12V to 14V without some kind of switching power supply? ;-)
    S.
     
  8. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

    Joined:
    Jun 21, 2006
    Messages:
    5,985
    Likes:
    511
    Location:
    Cleveland, OH, USA
    ONLINE
  9. Hero999

    Hero999 Banned

    Joined:
    Apr 6, 2006
    Messages:
    14,902
    Likes:
    79
    Location:
    England
    The chances are the device will work from 12V so a 14V supply is not required so building one would be a total waste of time.
     
    Last edited: Jul 18, 2008
  10. saturn1bguy

    saturn1bguy New Member

    Joined:
    Nov 12, 2007
    Messages:
    360
    Likes:
    1
    Location:
    Great Salt Lake
    Hero may be right here. But if you still want to do this, go to National's website and run their WebBench software. You can design and simulate your circuit before building it. It will assist with all the parts values.
     
  11. mneary

    mneary New Member

    Joined:
    Feb 27, 2007
    Messages:
    4,502
    Likes:
    67
    Location:
    California USA
    You probably can't.;)

    Hero was saying that if you don't really need 14V then you don't need to worry about generating it.
     
  12. Anti-Hacker

    Anti-Hacker New Member

    Joined:
    Nov 12, 2012
    Messages:
    1
    Likes:
    0
    Hey there! need some help. I have a 12V/2.3AH RESERVE-battery and I have a 12V battery in my vehicle. Can I charge me 12V/2.3AH RESERVE-battery with my cars battery using this circuit i.e. stepping up the DC voltage and then charging me RESERVE battery. Will it be OK?
     
  13. tcmtech

    tcmtech Well-Known Member Most Helpful Member

    Joined:
    Feb 22, 2009
    Messages:
    6,680
    Likes:
    430
    Location:
    Sawyer, North Dakota, USA
    I would just connect it to your vehicles electrical system and start the engine.

    It will automatically charge your battery being the alternator puts out around 14.4 VDC when the engine is running.

    No reason to over complicate the simple.
     
  14. sprinter312

    sprinter312 New Member

    Joined:
    Oct 17, 2012
    Messages:
    4
    Likes:
    0
    Location:
    St.Annes , Lancashire UK :)
    The best way is to use a 12v relay , connect a live from the switched side of the fuse box to one of the trigger contacts & the other to the thin wire leaving the alternator , that trips the warning light on the dash . When the alteranto begins to charge the wire goes to ground & completes the circuit energising the relay .

    You then simply use a suitable guage fo wire from the vehicle battery to the relay WITH A FUSE IN LINE ! & continue from the relay to your second battery .

    If you want to be really lazy car accessorie shops & caravan/camping stores sell split chrge relay kits that are pre wired .

    Use of he relay stops your secondary battery supplying power when starting the vehicle

    hope it helps

    Oh 35+ years working on cars / trucks / boats Etc.
     

Share This Page