PO89ZB , an inline DC filter for SMPS wall warts . Preamps, HPA, Korg NuTube, etc

Did you build and actually tested it?

Not yet, waiting for the parts to arrive, which have been shipped.

These simulations assume the source power supply (SMPS) output impedance is around 0.1 ohms, which seems like a reasonable simulation guess for a 32V 5A power supply. I have been assuming the load can range from around 500 ohms to 7 ohms. The application is for a cheap PS driving the Aiyima 04. The PC board RLC parasitics in the simulation are an educated guess. I may go measure the SMPS output impedance, later.
 
Member
Joined 2011
Paid Member
I grabbed the datasheet of a fairly typical 150 watt SMPS, made by Mean Well, attached below. It says the output voltage's load regulation (0% to 100% of full rated load --- page 2 row 9) is plus or minus 0.5%. So on a 5A, 32V supply that'd be 0.16V, giving Zout = (0.16 volts / 5 amps) = 0.032 ohms. The entire 5A current path would need to be similarly low impedance, to avoid excess voltage sag.

_
 

Attachments

  • LRS-150-SPEC.PDF
    685.8 KB · Views: 105
Simulation can only give an approximation of reality, but the SMPS source impedance change from 100 m-ohms to 32 m-ohms gives the same result. The true test is in measurement and results. :dice:

It seems the image attachments must come from a hosted site URL. I tried drag and drop, but it seems corrupt the forum web page.:irked:

https://www.diyaudio.com/archive/gallery/index.htmlhttps://www.diyaudio.com/archive/gallery/index.html
"Please note: This is a permanent archive. Due to this gallery module becoming incompatible with the latest version of the forum software, we have frozen/archived all old galleries (and their images) and made them read-only. No new images can be uploaded, all old images are still accessible, all images and links to those images will still work, and this archive will remain permanently....."
 
Last edited:
Hi,

Are you sure you use that function for attachements?

Claude
 

Attachments

  • Capture d’écran 2021-01-31 à 07.36.36.png
    Capture d’écran 2021-01-31 à 07.36.36.png
    306.9 KB · Views: 130
This is a re-post of the 3 stage filter from local image (not hosted elsewhere).


This is an experimental design 3 stage filter for 36V 6A application, one could use the 63V capacitor for 48V applications. Waiting for parts.
 

Attachments

  • Layout-3-stage-LC-filter-6A-s.JPG
    Layout-3-stage-LC-filter-6A-s.JPG
    204.8 KB · Views: 1,536
  • AC-sim-32mohm-SMPS-7ohm-load.JPG
    AC-sim-32mohm-SMPS-7ohm-load.JPG
    68.8 KB · Views: 484
  • Tran-32mohm-SMPS-RL=7ohm.JPG
    Tran-32mohm-SMPS-RL=7ohm.JPG
    85.4 KB · Views: 446
  • 6A-filter-Parts-List-text.txt
    660 bytes · Views: 87
  • Simulation-schematic-AC-3-stage-LC-6A.JPG
    Simulation-schematic-AC-3-stage-LC-6A.JPG
    135.7 KB · Views: 469
Hi, everyone. I ordered 50 of these from JLPCB, for about $30 (so about 60 cents each), and am ready to distribute them to people who want them. Here's the deal: If you want one or two and are in the US, then they are free. If you want more than two or are not in the US, then I'll ask you to toss me a couple bucks to cover the costs and shipping. PM me if you want some.


Note also: Mouser BOM here for one click ordering. This does not include DC jacks, etc, as on the original BOM.