Digital Drive

• A question - Christine Tham 15:01:57 03/04/07 (4)
  In Reply to: Nobody seems to take jitter seriously unless there is math in the paper :) [nt] posted by Ted Smith on March 4, 2007 at 14:31:18:

  I am not an expert on switching power, but it just occured to me that there may be possible to design a switching supply that tries to minimise logic induced modulation and back EMF (for example, by altering the switching frequency).

  Any comments?

  May help explain why some designers are using switching power supplies in high end players.
  
  

  ---

  • Re: A question - Ted Smith 15:10:07 03/04/07 (3)
    In Reply to: A question posted by Christine Tham on March 4, 2007 at 15:01:57:

    Howdy

    I'm no expert there either, but it doesn't seem likely to me. Good ground planes, trace routing, trace impedance management, etc. as well as local power supply filtering and appropriate bypass caps, etc. make all the difference. (Once again I'm talking as a software guy that spent too much time in the lab helping with system debugging, not as a hardware guy.)

    -Ted
    
    

    ---

    • Re: A question - Christine Tham 15:26:26 03/04/07 (2)
      In Reply to: Re: A question posted by Ted Smith on March 4, 2007 at 15:10:07:

      Well, the reason I'm speculating is based on some comments from Bruce Candy regarding the design of the Halcro amps.

      Anyway, I'm just wondering whether it's possible to design a switching power supply that switches at a rate synchronized to the master clock, and draws power from different parts of the cycle for different parts of the circuit. Some of the more sophisticated PC power supplies already do similar things to stabilise the load to the CPU vs the graphics card.

      I wouldn't like to be person doing such a design - I don't need the headache!
      
      

      ---

      • Re: A question - Ted Smith 16:13:26 03/04/07 (1)
        In Reply to: Re: A question posted by Christine Tham on March 4, 2007 at 15:26:26:

        Howdy

        Yep, syncing the switching supply freq to the important local clocks can be useful (for example we did it in a video monitor to hide the power supply noise in the retraces.)

        But if the switching supply freq isn't perfectly synced with the clock(s) in question you have to worry about beating and sometimes it's hard to vary it as fast you might need to if the incoming clock rate is changing... Also you obviously need to handle the edge cases like making sure that unplugging the DAC input doesn't cause the power supply to shut down :)

        -Ted
        
        

        ---

        • Hey, nobody said it was going to be easy - which is why I'm not volunteering to design it :-) (nt) - Christine Tham 16:21:06 03/04/07 (0)
          In Reply to: Re: A question posted by Ted Smith on March 4, 2007 at 16:13:26:

          .
          
          

          ---

This post is made possible by the generous support of people like you and our sponsors:

Parts Connexion

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---