48V to 12V DC converter

Discussion in 'General Electronics Chat' started by indiantuktuk, Mar 27, 2009.

  1. indiantuktuk

    Thread Starter New Member

    Mar 27, 2009
    Hi :),

    I was simulating DC converter schematics using LT Spice (freeware). (Could be downloaded from http://www.linear.com/designtools/software/ltspice.jsp ) Enclosed the attachment.

    Does anyone having exposure to developing DC DC converter advice me if this works. The data is as below
    Input - 48V
    Output - 12V
    Output Amps - 20 amps

    Typically I get a spike of 20V at the startup and then the output is constant. Any suggestion to overcome this phenomena is welcome.

  2. smanches

    New Member

    Mar 27, 2009
    Typically you just have a delay in starting the PWM controller, then have it ramp up the duty cycle slowly starting from 0%. As soon as you hit your target voltage, then switch it into it's fast acting regulation mode.

    I don't have any way to look at your schematic right now to give any more details. Sorry.
  3. Darren Holdstock

    Active Member

    Feb 10, 2009
    Sounds like the circuit is marginally stable due to underdamping. Tweak the loop compensation.