The Mega SMPS Design Cheat Sheet!

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  • Th3_uN1Qu3
    Believe in
    • Jul 2010
    • 6031
    • Romania

    #1

    The Mega SMPS Design Cheat Sheet!

    To stop bumping that old thread, and because i have made significant improvements to the spreadsheet, i decided to post it in a new one.

    I have added half bridge and full bridge calculations. And there's LOTS more goodies to come, i'm just getting started. What i promise you is that there will be MORE variables, like voltage drops of transistors and diodes, to provide the best possible accuracy. And there's more... but i'll keep it a surprise for the time being.

    There will also be more tips on snubbers and voltage spike elimination devices, as once you have a working supply, lowering its noise level is the next challenge. I'm also working on a fresh-out-the-oven low power split supply of my own design for use in standby/driver circuits for half- and full bridge supplies. Say no to flimsy and expensive IC drivers - with a bipolar driver supply, a small and easy to make gate drive transformer is all you need to drive ANY configuration of switching devices.

    And beyond this, i also have real life and school to attend to... I'm a busy guy.

    PS. You know, it occured to me that there's no "SMPS for Dummies" book. I might just write one someday.
    Attached Files
    Originally posted by PeteS in CA
    Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
    A working TV? How boring!
  • 370forlife
    Large Marge
    • Aug 2008
    • 3112
    • United States

    #2
    Re: The Mega SMPS Design Cheat Sheet!

    http://www.amazon.com/exec/obidos/AS...00/hsecrets-20

    I heard that is supposed to be a pretty good book as far as a "SMPS for dummies" type thing.

    Comment

    • Th3_uN1Qu3
      Believe in
      • Jul 2010
      • 6031
      • Romania

      #3
      Re: The Mega SMPS Design Cheat Sheet!

      Preachin' to the choir... I have it already. I even recommended it in the readme section of the spreadsheet that you didn't bother to read. It's comprehensive but it's got too much math for a dummy to understand... and some of the results of the equations are pulled out of the blue with no explanation on how he got there. It's a good book (especially the chapter on control loop compensation), but there are easier ones.

      Edit: Uh, one little thing i haven't mentioned. For bridge topologies the value you get is the total number of secondary turns including the center tap. That means, you wind half the number you get in the spreadsheet, pull out the center tap, then wind the other half in the same direction.
      Last edited by Th3_uN1Qu3; 04-20-2011, 02:09 PM.
      Originally posted by PeteS in CA
      Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
      A working TV? How boring!

      Comment

      • Th3_uN1Qu3
        Believe in
        • Jul 2010
        • 6031
        • Romania

        #4
        Re: The Mega SMPS Design Cheat Sheet!

        Updated.
        • Fixed half and full bridge inductor size (it came up as double what it should be, bridge topologies use full wave rectifying so ripple frequency is effectively double the switching freq)
        • Adjusted a constant in the inductor equation


        Happy building.
        Attached Files
        Originally posted by PeteS in CA
        Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
        A working TV? How boring!

        Comment

        • Th3_uN1Qu3
          Believe in
          • Jul 2010
          • 6031
          • Romania

          #5
          Re: The Mega SMPS Design Cheat Sheet!

          Stay tuned, even more goodies coming up.
          Originally posted by PeteS in CA
          Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
          A working TV? How boring!

          Comment

          • Th3_uN1Qu3
            Believe in
            • Jul 2010
            • 6031
            • Romania

            #6
            Re: The Mega SMPS Design Cheat Sheet!

            Annnnddd... Updated! Check out the awesome new compensation components calculator. Enjoy. I did the math so YOU don't have to.
            Attached Files
            Last edited by Th3_uN1Qu3; 10-15-2011, 02:38 PM.
            Originally posted by PeteS in CA
            Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
            A working TV? How boring!

            Comment

            • Rulycat
              Badcaps Veteran
              • Apr 2010
              • 724
              • United Kingdom

              #7
              Re: The Mega SMPS Design Cheat Sheet!

              This could be very handy, thankyou.

              Comment

              • Th3_uN1Qu3
                Believe in
                • Jul 2010
                • 6031
                • Romania

                #8
                Re: The Mega SMPS Design Cheat Sheet!

                Updated.
                • Fixed a real big oopsie in the primary cap ripple calculator
                • Ripple voltage is now shown as RMS
                • Added calculations for 60Hz mains
                • Other minor additions


                Enjoy.
                Attached Files
                Originally posted by PeteS in CA
                Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                A working TV? How boring!

                Comment

                • Th3_uN1Qu3
                  Believe in
                  • Jul 2010
                  • 6031
                  • Romania

                  #9
                  Re: The Mega SMPS Design Cheat Sheet!

                  Added Push-Pull converter.
                  Attached Files
                  Last edited by Th3_uN1Qu3; 04-17-2012, 09:13 AM.
                  Originally posted by PeteS in CA
                  Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                  A working TV? How boring!

                  Comment

                  • Th3_uN1Qu3
                    Believe in
                    • Jul 2010
                    • 6031
                    • Romania

                    #10
                    Re: The Mega SMPS Design Cheat Sheet!

                    Updated. I'm surprised noone caught this till now - the inductor values calculated were wrong (too large). It's not that the power supply wouldn't work with such a large inductor, but it needs more wire, makes compensation a tad more difficult, and increases the voltage spike when suddenly disconnecting a big load.

                    I apologize for the error, all's good now.
                    Attached Files
                    Originally posted by PeteS in CA
                    Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                    A working TV? How boring!

                    Comment

                    • Pentium4
                      CapXon Be Gone
                      • Sep 2011
                      • 3741
                      • USA

                      #11
                      Re: The Mega SMPS Design Cheat Sheet!

                      Definitely going to download that excel spreadsheet. So if you can find that book cheap, is it worth getting?

                      Comment

                      • Rulycat
                        Badcaps Veteran
                        • Apr 2010
                        • 724
                        • United Kingdom

                        #12
                        Re: The Mega SMPS Design Cheat Sheet!

                        I've got the second edition (released 2012) and it's excellent. My brain has exploded though. I suspect it will need many passes reading it as well as experimental testing to understand even half of it. The bits that throw me the most are the equations requiring partial differentiation. Agh!

                        Comment

                        • Pentium4
                          CapXon Be Gone
                          • Sep 2011
                          • 3741
                          • USA

                          #13
                          Re: The Mega SMPS Design Cheat Sheet!

                          Originally posted by Rulycat
                          I've got the second edition (released 2012) and it's excellent. My brain has exploded though. I suspect it will need many passes reading it as well as experimental testing to understand even half of it. The bits that throw me the most are the equations requiring partial differentiation. Agh!
                          Sweet, I'll probably get it so my brain can explode as well. In a good way, not a HKFA PSU way

                          Comment

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