The Belleson Superpower, the ultimate voltage regulator ... ? - Page 5 - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th April 2011, 02:35 PM   #41
diyAudio Member
 
vdi_nenna's Avatar
 
Join Date: Oct 2000
Location: PA, USA
Blog Entries: 1
Send a message via Yahoo to vdi_nenna
Hi,

I have a set of Belleson +24v (LM317 type) and will be making an external power supply for a CD player soon. I can't compare it to another regulator, but I can A/B with or without the external. Will let you know how it sounds.

Vince
__________________
I build, therefore I am.
  Reply With Quote
Old 13th April 2011, 02:47 PM   #42
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Quote:
Originally Posted by belleson View Post
You don't say how your transformer test circuit is connected, is it possible that DC current is saturating the core and skewing the measurements? This could cause errors that depend on regulator current consumption.

We use an active driven source to feed the input rather than a transformer, and are working on a PSRR test circuit that uses an LM3886 to drive the input with DC+AC.
The transformer isn't saturating -- it's good up to about 600mA DC. See Audio Precision TN-106.

I use the 1995 TAA Articles as a reference point. Jung specified a load of 100R//100uF. You may be using a purely resistive load.

I've used batteries, an HP6271B and a Tek PS5010 to drive the regulators. The HP6271 can be "modulated" but it requires de-racking it.

The output impedance of the AP2722 is 20 ohms unbalanced, 40 ohms balanced. The schematic below shows a low impedance driver WJ used for his experiments which overcome this issue. (It's a variant of the Pooge 5.1 regulator). I simmed it to be ~2.4 milliOhms. Variously, WJ appears to have used 1.4V p-p and 1V p-p, for his line rejection tests. Using 1V RMS is putting a lot more burden on the regulator, I agree.

Line rejection is easier to measure than output impedance. The noise tests use a balanced, low noise line driver set to 100X.

For the diode example you give, do you want to specify the diode and leakage inductance of the trafo you were using? Almost looks like my wife was using her hair blower!
Click the image to open in full size.
  Reply With Quote
Old 13th April 2011, 05:18 PM   #43
diyAudio Member
 
Join Date: May 2005
Location: Southeast USA
Quote:
Originally Posted by stormsonic View Post
@belleson
post #35, second picture with measurement results: are you using HPF ?
The FFT software has a "Remove DC" selector which is active. I also believe the hardware used for this measurement has an input coupling capacitor.
  Reply With Quote
Old 13th April 2011, 08:51 PM   #44
diyAudio Member
 
stormsonic's Avatar
 
Join Date: Aug 2008
Belleson, thank you very much. Yes, Visual Analyzer has a lot of options and filters.
Can you please show as a comparision plot between noise floor and regulator's output, all filters disabled (including DC removal), Hanning and Averaging=100 ?
  Reply With Quote
Old 14th April 2011, 02:46 AM   #45
diyAudio Member
 
Join Date: May 2005
Location: Southeast USA
Quote:
Originally Posted by jackinnj View Post

The output impedance of the AP2722 is 20 ohms unbalanced, 40 ohms balanced. The schematic below shows a low impedance driver WJ used for his experiments which overcome this issue. (It's a variant of the Pooge 5.1 regulator). I simmed it to be ~2.4 milliOhms. Variously, WJ appears to have used 1.4V p-p and 1V p-p, for his line rejection tests. Using 1V RMS is putting a lot more burden on the regulator, I agree.
The low impedance driver is exactly the topology we used in PSRR tests, except of course the modulated regulator is a Superpower. The problem with this topology is the limited output frequency. This positive regulator, with load capacitor C2=0.1uF and load resistor R12=350 Ohms, can go to about 42KHz before the negative going signal starts to limit. With 1uF on the input of the DUT regulator, frequency limits at 4.2KHz, 10uF/420Hz, etc.

This is because the output has an active current source but a passive current sink limited by the 350 Ohm R12. When Vout modulation peaks and begins to decrease, R12 has to discharge C2 and any capacitance on the DUT input. This is why our PSRR measurements go only to 5KHz and why we're looking at a different driver such as LM3886, which can sink as well as source current.

At f(max), the sine wave does not degrade gracefully into a triangle but instead the low-going half-wave slew limits and decreases Vmax amplitude, distorting the measurement reference value of 1Vpp (or in your test 1Vrms).

Quote:
Originally Posted by jackinnj View Post
For the diode example you give, do you want to specify the diode and leakage inductance of the trafo you were using? Almost looks like my wife was using her hair blower!
I don't know the transformer and diode leakage inductance, it's the raw output from the rectifier in a Tripp-Lite PR-10b. The "hair blower" spectrum is typical of (approximately) sawtooth full wave rectifier ripple, only the textbooks don't show so many harmonics.

Last edited by belleson; 14th April 2011 at 02:58 AM.
  Reply With Quote
Old 14th April 2011, 03:21 PM   #46
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Quote:
Originally Posted by belleson View Post
The problem with this topology is the limited output frequency. This positive regulator, with load capacitor C2=0.1uF and load resistor R12=350 Ohms, can go to about 42KHz before the negative going signal starts to limit. With 1uF on the input of the DUT regulator, frequency limits at 4.2KHz, 10uF/420Hz, etc.
R12 is in parallel with the sense network (2.43K +1.82K), so the pole is closer to 5kHz. R1,C1 is a zero @655kHz.
Here is the response of the Rail Driver without compensation:

Click the image to open in full size.

and with compensaton:
Click the image to open in full size.
  Reply With Quote
Old 14th April 2011, 04:55 PM   #47
diyAudio Member
 
Join Date: Jul 2003
Location: Bath, UK
Thanks belleson, your last posts exactly explained what I was curious about.

Looks like great performance for only 9 parts.
  Reply With Quote
Old 14th April 2011, 06:46 PM   #48
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Everything looks better with the Jung regulator driver -- it's pumping out at 18V. The Belleson, indeed looks much, much better with this setup. I think I was over-driving all of these regulators with way too much ripple.

This is, essentially the setup I'm now using to measure LR.

Click the image to open in full size.

Last edited by jackinnj; 14th April 2011 at 06:48 PM.
  Reply With Quote
Old 14th April 2011, 07:53 PM   #49
diyAudio Member
 
Join Date: Jan 2007
Quote:
Originally Posted by belleson View Post
The LM317 was tested with Cin=0.1uF, Cref=10uF, Cout=1uF, R1=270 Ohms, R2=2K Ohms, Vin=30V, Vout=10.8V. An 8 Ohm load was switched from Vout to ground using a D880-Y power NPN. The SPJ Superpower uses a standard D44H11 or D45H11 output transistor.

If you are planning to use regulators in parallel, I suggest the LT3080 or something similar, not LM317.
Brian,

The LM317 setup seems reasonable and I find your suggestion to use an LT3080 refreshingly honest (although it still is an expensive IC).

Thank you.

--
Greetz,
MatchASM
  Reply With Quote
Old 15th April 2011, 03:54 AM   #50
diyAudio Member
 
Join Date: May 2005
Location: Southeast USA
Quote:
Originally Posted by jackinnj View Post
R12 is in parallel with the sense network (2.43K +1.82K), so the pole is closer to 5kHz. R1,C1 is a zero @655kHz.
Here is the response of the Rail Driver without compensation:

{images clipped}
This is fine, but it's not a bandwidth problem it's a slew rate problem. If the tested regulator has any capacitor C5 on the input, as some require for stability, this affects the negative slewing of the rail driver output. The maximum negative slew rate is set by

dV/dt = 2pi(f)Vmax where Vmax=Vpk of the sine wave (not pk-pk)

Current I5 flows into and out of C5 as the rail output oscillates:

I5 = C5(dV/dt), and the dV/dt is set by I5 = Vout/R12

Combine these and you get

Vout/R12 = 2pi(f)(Vmax)(C5)

You can plot C5 vs. f to see the maximum clean sine frequency per uF, or choose a value for C5 and plot the maximum sine amplitude vs. frequency.

The two oscillogram simulations are using C5=1uF, the first is at 10Khz and you can see the linear slew of the green Vout as it hits the limit (red is the modulation signal V2). The second one is 40KHz and the output barely makes it back to mid-scale before the next cycle comes along. This is what I was referring to in post #45 when I said the test signal to the DUT is no longer a valid amplitude, nullifying the resulting measurements w.r.t. 0dB.

Note that V2 was inverted and scaled by +18Vdc to be visible and compared to rail driver Vout.

This is much less of a problem if the tested regulator has no input capacitor, but you have to be careful.
Attached Images
File Type: png Jung_Rail_Drv_Sch.png (10.5 KB, 893 views)
File Type: png Jung_Rail_Driver_10KHz.png (12.6 KB, 364 views)
File Type: png Jung_Rail_Driver_40KHz.png (13.4 KB, 135 views)

Last edited by belleson; 15th April 2011 at 03:58 AM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
High Voltage Huge Storage CAPS for that Ultimate Valve Amp col Tubes / Valves 0 11th December 2009 03:37 AM
Ultimate Amp with High offset voltage glen65 Car Audio 4 16th October 2007 12:19 AM
Ultimate shunt regulator Uchi Deshi Power Supplies 8 5th May 2006 08:16 PM
Voltage regulator annex666 Solid State 1 27th August 2003 03:50 PM
Voltage regulator help! kasra Solid State 7 23rd November 2002 03:07 PM


New To Site? Need Help?

All times are GMT. The time now is 01:20 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2