240 Vac to 10 Vdc Converter design. Need help~~~

Discussion in 'The Projects Forum' started by airforce1121, Jul 20, 2011.

  1. airforce1121

    Thread Starter New Member

    Jul 19, 2011
    Hi all,

    I had a problem designing the circuit of AC-DC converter.
    Any formula to calculate the value of component used in the circuit?
    I want to build an 240Vac to 10Vdc converter, with 8A current limit.
    CIrcuit diagram needed

  2. simo_x


    Dec 23, 2010
    It is a classical Transformer >> Diode Bridge >> Capacitor >> Voltage Regulator implementation.

    Normally, it is better you buy a transformer that could give you the 8A, since it depends strongly from its construction, and many formulas take place here.

    Of course, the diode bridge should be able to support the 8A output rectified current, if more better..

    For the 10V DC you could be able to arrange it with a 7812 and drop the voltage a little bit with resistors or a zener, or better taking advantage of the same device's voltage drop... At the moment I have no better idea about. Maybe some expert here have better than mine. Finally, for the 8A, which a normal 78xx regulator could not supply even mounted on the biggest heatsink in this world, additional external transistor/s is/are required. If you check the datasheet for 78xx series from National, some example should be represented for current source more than ~1A. Starting from this you could design a scheme, post it here and we will help you in the better way we can.

    Here, I report the link of NEETS series provided by Bertus recently to me.. There, Module 7 should be of your interest.

    Last edited: Jul 20, 2011
  3. praondevou

    AAC Fanatic!

    Jul 9, 2011
    I think first you should decide if you want a SMPS or the solution simo_x suggested.
  4. SgtWookie


    Jul 17, 2007
    The "AC-DC converter" implies a SMPS solution.
    The old-fashioned linear supplies are heavy, bulky, expensive, and inefficient - but provide a very "clean" output.

    I don't know if you are determined on building your own SMPS or not, but you might consider converting an ATX form factor computer power supply to suit your needs. They output +12v at high current, as well as +5v, +3.3v, -12v and -5v. After determining which switching regulator IC is being used in the one you convert, it's merely adjusting the resistors in the feedback loop to change the 12v output to 10v.

    It's just a cheap an inexpensive way to get there quickly.
    Last edited: Jul 20, 2011