Help With Circuit Design

Discussion in 'General Electronics Chat' started by Francois_Swart, Jun 13, 2009.

  1. Francois_Swart

    Thread Starter Member

    Jun 4, 2009
    14
    0
    I have this circuit that i need to design, but i dont know how!

    The paramaters are as follows:

    11-15V DC 500mA adjustable output PSU with 110V or 220V selectable input voltage.

    The unit wil be used to charge a 7,2 Ah sealed lead acid battery, it has to have an additional output that indicates that the psu is functioning i.e. blocking diode. Further the unit has to have a pic microcontroler monitoring the battery voltage if the main AC voltage has failed. If the Battery voltage drops below a certain point for longer than sixty seconds the pic must switch the state of an input and start a 5min timing cycle. At the end of the timing cycle the battery must be disconnected from the circuit (I thought of breaking the currunt flow through a self-latching relay). Also when the main AC voltage is restored the battery must be reconnected to the circuit in order to be recharged.

    Any ideas or suggestions wil be appreciated.

    Thanx!
     
  2. Mike Mandaville

    Active Member

    May 27, 2009
    81
    1
    PSU

    That's where I stopped reading.
     
  3. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Power Supply Unit.
     
  4. Mike Mandaville

    Active Member

    May 27, 2009
    81
    1
    Good grief.
     
  5. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    A really, really good reference...

    The Battery University

    This project has been addressed many different ways, I would suggest a thorough search on AAC.
     
  6. Francois_Swart

    Thread Starter Member

    Jun 4, 2009
    14
    0
    This is what I've done so far. Comments and suggestions will be apreciated.
     
    • PSU.pdf
      File size:
      74 KB
      Views:
      36
  7. steinar96

    Active Member

    Apr 18, 2009
    239
    4
    Francois. Your circuit is very fishy. I reccommend you look for a working schematic and attempt to build a circuit from that schematic. You seem to need at least a working circuit you can modify afterwards to suit your needs.
     
  8. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    JP1 is good for a flash, a puff of smoke, and a blown fuse, possibly an electrical fire.. The other coil has a permanent dead short across it, continueing below JP1. I suspect you were after symmitry, but it missed.

    VR1 also has a problem. You have a variable voltage, but zero regulation. Why even bother with a 15V regulator before it. I suspect you were trying to show the 15V regulator as variable.

    The PDF drawing is sideways, which makes it very hard to read. I had to rotate it 270° to see it.
     
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