Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Simplistic Mosfet HV Shunt Regs
Simplistic Mosfet HV Shunt Regs
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 10th August 2009, 01:52 AM   #471
iko is offline iko  Canada
diyAudio Moderator
 
iko's Avatar
 
Join Date: May 2008
Location: Toronto
Simplistic Mosfet HV Shunt Regs
Default Re: wild idea :)

Quote:
Originally posted by disco
Not being very gifted with solid state I ventilated this [OT] idea some time ago to Gary Pimm.
It's more appropriate to larger amps than to sputs but it might be worth the effort.

In order to optimize a shunt regulators' efficiency it should be able to change its set current when
power consumption is demanding such. A kind of servo action. Would it be possible to sense the
ampliers' current draw ahead of the actual amplification and adjust the CCS as needed?
The biggest bottleneck might be the slowness of the current rise.

A very simplistic (hey, where did I hear this before ) solution would be a 10 to 20% increase
depending on the rotation of the volume control.
I've been thinking about this for some time, but I'd be reluctant to use something more automatic. If anything, I'd do first a simple and reliable system (attenuator?) that would choose between several pre-set resistors, with a nice analog display of idle shunt current, and regulated voltage.

I have no problem with a nice power amp powered with a shunt regulated. If I was into efficiency I'd be all over class-d stuff. But that's just me.
  Reply With Quote
Old 10th August 2009, 02:06 AM   #472
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic Mosfet HV Shunt Regs
Default Re: wild idea :)

Quote:
Originally posted by disco
Not being very gifted with solid state I ventilated this [OT] idea some time ago to Gary Pimm.
It's more appropriate to larger amps than to sputs but it might be worth the effort.

In order to optimize a shunt regulators' efficiency it should be able to change its set current when
power consumption is demanding such. A kind of servo action. Would it be possible to sense the
ampliers' current draw ahead of the actual amplification and adjust the CCS as needed?
The biggest bottleneck might be the slowness of the current rise.

A very simplistic (hey, where did I hear this before ) solution would be a 10 to 20% increase
depending on the rotation of the volume control.
Krell's plateau bias could be translated in plateau shunt ICCS. Just another wild idea.
  Reply With Quote
Old 10th August 2009, 03:04 AM   #473
iko is offline iko  Canada
diyAudio Moderator
 
iko's Avatar
 
Join Date: May 2008
Location: Toronto
Simplistic Mosfet HV Shunt Regs
Nothing wrong with brainstorming. The crux of the Krell idea seems to be the stepped increase/decrease of the bias current for a fixed time according to some algorithm based on how dynamic the signal is. The steps are discrete, sort of like shifting one gear up/down at a time. Not sure of the details.

I don't think that an automatic change of the shunt current would work, UNLESS there is another shunt before the shunt Only that way the current suddenly demanded by the original shunt could be given timely enough.

However, something that does not react to the music might work, and instead, react to a low limit of the the actual shunt current. Monitor the shunt current, and as soon as it is below a certain threshold, increased it by a predetermined amount, for a number of fixed times.
  Reply With Quote
Old 10th August 2009, 03:54 AM   #474
iko is offline iko  Canada
diyAudio Moderator
 
iko's Avatar
 
Join Date: May 2008
Location: Toronto
Simplistic Mosfet HV Shunt Regs
Quote:
Originally posted by AndrewT

But a shunt regulator, surely, can't be a candidate for a power amp's supply?
I would think if one is going down this route one would select a series regulator topology.
Maybe I'm wrong.
From a technical standpoint, I think it can be done. The obvious disadvantage is the power dissipation. But there are people who would still get a Veyron, even though you get 9 miles per gallon (city), which is about
30 liters of gas every 100kms. Would a power amp sound better with a shunt regulator? Let's find out.
  Reply With Quote
Old 10th August 2009, 06:18 AM   #475
dia thien thai is offline dia thien thai  United States
diyAudio Member
 
Join Date: Dec 2006
Location: USA
Hi Salas! thank you you help me!
I want to ask him about the principles of operation of this circuit shunt regulator ???
You can show me the parameters to be measured by the R out of the shunt regulator??? Noise and Humm

I need one circuit for the pre with voltage: output 260v / 80ma one channel, and can adjust the voltage out! With vi in 300V to 350V!
You can give me one cricuit for my pre!
Thank
You can see the cricuit ! how The value and C- R-C befor shunt regulator???
Attached Images
File Type: jpg shal-hoi.jpg (99.9 KB, 687 views)
  Reply With Quote
Old 10th August 2009, 08:08 AM   #476
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic Mosfet HV Shunt Regs
All the principles have been discussed in the thread. If you have read the thread and you still don't see how to scale it, clamp it, start it, calculate the voltage drop on its CRC pre filter etc. then, I am sorry I don't give targeted circuits on a plate anymore to members I have no record of their contribution here after what happened in the DC B1 group buy thread. I am sorry, its not you, its recent abuse of open fixed application info. I have already given you some idea for the 260mA you asked for.
  Reply With Quote
Old 10th August 2009, 10:40 AM   #477
AndrewT is offline AndrewT  Scotland
R.I.P.
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally posted by ikoflexer
From a technical standpoint, I think it can be done. The obvious disadvantage is the power dissipation.
of course, it can be done. As you point out some may want to do it to hear the "best" audio they can achieve.

Here's why I will not be trying to achieve that shunt regulator + power amp.
Take a typical ClassAB 100W into 8r0 amplifier.
PSU is a 50Vdc with +-20mF smoothing.
Maximum output current is ~15Apk.
Let's assume 2/3 will come from the capacitors.
That means our regulated PSU must be capable of recharging the caps and supplying the ClassAB amplifier from the remaining 1/3 of maximum rating. I'll assume it has a CCS giving about 5A and that is capable of supporting the amplifier in all music reproduction conditions.
The regulated voltage is +-50Vdc
The nominal input voltage is +-60Vdc but will range between ~55Vdc to 65Vdc as mains supply varies.
The two CCS will have to dissipate ~15V * 5A = ~150W
The two shunts will have to dissipate 50V * ~4.9A = ~490W
Total regulator dissipation ~640W for a 100W amplifier playing at an average output level ~1W. And those numbers are for a single channel only.

I would rather go to full ClassA and regulate only the voltage amplifier stage supply.
__________________
regards Andrew T.
  Reply With Quote
Old 10th August 2009, 04:08 PM   #478
iko is offline iko  Canada
diyAudio Moderator
 
iko's Avatar
 
Join Date: May 2008
Location: Toronto
Simplistic Mosfet HV Shunt Regs
This shows even more that a step-controlled shunt current version would be very nice to have in such situations. If I were to do it now I'd probably use a simple PIC controller to monitor the shunt current and keep it at a pre-set threshold. I would think about the idle shunt current as the "reserve" current that should never get below some value, which would be dictate by the needs of the circuit that is powered with the regulator.
  Reply With Quote
Old 11th August 2009, 02:51 PM   #479
iko is offline iko  Canada
diyAudio Moderator
 
iko's Avatar
 
Join Date: May 2008
Location: Toronto
Simplistic Mosfet HV Shunt Regs
Tiny update; since the prototype from post #442 (implementation of post #412) seemed to work and was stable for a few days, I've hooked it up to the dht headphone amp I'm working on and here's the output of a 1kHz square wave. Only one channel at the moment, so I can't say how it sounds for real. Plus, the filament supply is not yet finished.

The square wave is generated by the scope for calibration, so I can't change its frequency
Click the image to open in full size.
  Reply With Quote
Old 11th August 2009, 03:06 PM   #480
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic Mosfet HV Shunt Regs
Is that horizontal part still double lined if you feed your calibration directly to the scope? Or there is a gremlin....
  Reply With Quote

Reply


Simplistic Mosfet HV Shunt RegsHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Regs - Shunt vs Series richie00boy Solid State 59 17th June 2017 04:59 PM


New To Site? Need Help?

All times are GMT. The time now is 06:52 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki