Power supplies and Microcontrollers - do they really get along?

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  • Th3_uN1Qu3
    Believe in
    • Jul 2010
    • 6031
    • Romania
    #1

    Power supplies and Microcontrollers - do they really get along?

    I'm seeing more and more power supply projects using micros. I don't think that's such a good idea - i'm quite apprehensive of letting a device that runs code control an offline SMPS for instance... But i see them even in higher power devices like spot welders and they seem to do fine.

    Have you had any first hand experience with microcontroller based power supplies? Is for instance a cheap PIC fast enough to run a 100kHz SMPS? I'd like to get started in micros and a custom SMPS controller sounds like a good idea. I have my own 555-based controller that i designed, but in some areas it leaves to be desired. A micro would allow for more expansion.
    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!
    Tags: None
    • redwire
      Badcaps Legend
      • Dec 2010
      • 3900
      • Canada
      #2
      Re: Power supplies and Microcontrollers - do they really get along?

      A PIC is fast enough but sensitive to EMI/RFI generated by the power electronics, which makes it crash. Your timer code must be perfect.

      I rarely see all MCU type SMPS controllers. Any mistakes in your software, or an MCU crash can blow up the power-semi's. After the smoke clears the question comes up "what happened?" and you have no idea, it's too late. So testing and debug is very difficult.

      Instead, I prefer a dedicated SMPS IC that gets controlled by an MCU (turn on/off/standby/Vout fine adjust etc.) If the MCU crashes or does something silly, no parts get damaged as the PWM IC keeps running and looks after things.

        Comment

        • PCBONEZ
          Grumpy Old Fart
          • Aug 2005
          • 10661
          • USA
          #3
          Re: Power supplies and Microcontrollers - do they really get along?

          My computer needs a power supply but my power supply doesn't need a computer.
          .
          Mann-Made Global Warming.
          - We should be more concerned about the Intellectual Climate.
          -
          Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
          - Dr Seuss
          -
          You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
          -

            Comment

            • ratdude747
              Black Sheep
              • Nov 2008
              • 17136
              • USA
              #4
              Re: Power supplies and Microcontrollers - do they really get along?

              sounds like a way to jack up the pricetag and reduce usable life...

              spot welders i can understand, as you want to get the amount of heat and therefore the amount of juice right on target... you don't want to overheat the metal, just fuse it. the reason you might want a microcontroller is so you ca select the metal to be welded and you can measure the resistance to calculate the correct power... the resistance is critical to making a spot weld work in the first place.
              sigpic

              (Insert witty quote here)

                Comment

                • japlytic
                  Badcaps Legend
                  • Oct 2005
                  • 2086
                  • Australia
                  #5
                  Re: Power supplies and Microcontrollers - do they really get along?

                  If I remember correctly, I have read about Gigabyte power supplies of which the output rails can be programmed.
                  My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.

                    Comment

                    • PCBONEZ
                      Grumpy Old Fart
                      • Aug 2005
                      • 10661
                      • USA
                      #6
                      Re: Power supplies and Microcontrollers - do they really get along?

                      I remember seeing some from someone? that called it 'programed' rails but in reality all it amounted to was adjustment pots to fine tune the OP voltage.
                      Mann-Made Global Warming.
                      - We should be more concerned about the Intellectual Climate.
                      -
                      Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                      - Dr Seuss
                      -
                      You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                      -

                        Comment

                        • Toasty
                          Badcaps Legend
                          • Jul 2007
                          • 4171
                          #7
                          Re: Power supplies and Microcontrollers - do they really get along?

                          The Delta DPS-700FB uses a PIC chip on the daughterboard. All the sense lines run into that board.

                          Which brings me to the question, can the PIC be reverse programmed? Is there a way to "get the code" and change the parameters?

                          From Scenic's post thread: https://www.badcaps.net/forum/showthread.php?t=5998

                          Pictures:
                          http://bambooz.pytalhost.net/badcaps...0/image016.jpg
                          http://bambooz.pytalhost.net/badcaps...0/image020.jpg
                          http://bambooz.pytalhost.net/badcaps...0/image028.jpg
                          http://bambooz.pytalhost.net/badcaps...0/image029.jpg

                          Toast
                          veritas odium parit

                            Comment

                            • Wizard
                              Badcaps Legend
                              • Mar 2008
                              • 2296
                              #8
                              Re: Power supplies and Microcontrollers - do they really get along?

                              Well, There are some plasma panel SMPSes that have microcontroller to show error by blinking a LED and some other functions.

                              Cheers, Wizard

                                Comment

                                • PCBONEZ
                                  Grumpy Old Fart
                                  • Aug 2005
                                  • 10661
                                  • USA
                                  #9
                                  Re: Power supplies and Microcontrollers - do they really get along?

                                  Originally posted by Toasty
                                  The Delta DPS-700FB uses a PIC chip on the daughterboard. All the sense lines run into that board.

                                  Which brings me to the question, can the PIC be reverse programmed? Is there a way to "get the code" and change the parameters?

                                  From Scenic's post thread: https://www.badcaps.net/forum/showthread.php?t=5998

                                  Toast
                                  LOL, I actually have one of those but never needed to peek inside.
                                  .
                                  Mann-Made Global Warming.
                                  - We should be more concerned about the Intellectual Climate.
                                  -
                                  Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                                  - Dr Seuss
                                  -
                                  You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                                  -

                                    Comment

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