Converting a Power Supply

Discussion in 'The Projects Forum' started by iONic, Aug 10, 2008.

  1. iONic

    Thread Starter AAC Fanatic!

    Nov 16, 2007
    Quick question...

    Can a DC Switching power supply be converted to an AC switching supply.?
    Is it as simple as removing the bridge rectifier and Cap?

    And one further question... would the current capacity change?

    Last edited: Aug 10, 2008
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    A switcher uses much higher than line frequency to run its transformer. Your proposal will not work. If you really want to run line frequency AC as the input, you will need to purchase a step down transformer made to use the line as the input - and it won't be a switcher, just a linear supply.
  3. Externet

    AAC Fanatic!

    Nov 29, 2005
    Removing the secondary rectifier and filtering will yield you a high frequency switching AC power supply that does not work because the primary side needs feedback to regulate the duty cycle, and that feedback comes from a DC output level that does not exist any more.

    But you can leave all intact and tap from the secondary of the switching transformer, which will give you a high frequency AC power supply with the same current capability.

  4. iONic

    Thread Starter AAC Fanatic!

    Nov 16, 2007

    And now that you mention it I should have know this. Got my head loosely screwed on today!

  5. Tahmid

    Active Member

    Jul 2, 2008
    Hi iONic,
    Your head is not loosely screwed today. It is tightly screwed and more tightly than average men, because your question is an intelligent one and this sort of out of track ideas/questions are required to learn something intimately.
    Yes, a Dc power supply can be converted to AC switching supply. It is as simple as you have said- removing bridge rectifier and capacitor. After removing those from output, you get high frequency AC. Question is, what you will do with that AC? You can do one thing, after removing rectifier and capacitor, if you can filter that with a Low Pass filter to remove modulating carrier frequencies, you can get 50 hertz AC, which will be useful for you. In this way, you can convert that high frequency AC in many pattern for further use. If you do like that, only than removing capacitor and rectifier will be justified.

    Thanks for your intelligent question.
  6. iONic

    Thread Starter AAC Fanatic!

    Nov 16, 2007

    So in other words, after filtering the carrier frequencies I would get a 60Hz(USA) AC. Is this a square wave or sine wave? Being a 5V supply it could be used as a fairly accurate clock pulse to other logic components.