Class H switching - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 20th December 2011, 03:33 PM   #1
diyAudio Member
 
Join Date: Jan 2006
Location: Visayas Region
Send a message via AIM to clovi_kate Send a message via MSN to clovi_kate Send a message via Yahoo to clovi_kate
Default Class H switching

hi guyz..

I have a question about class h amps having a mosfets switch. At time when amp is at full state (maximum operation), does the voltage across drain to source of mosfet reaches zero? (Vds=0)?.. And when the mosfets starts to switch to the voltage, does it increase the voltage slowly or it will switch to its highest voltage right away?..
__________________
  Reply With Quote
Old 20th December 2011, 06:23 PM   #2
diyAudio Member
 
Join Date: Jan 2006
Location: Visayas Region
Send a message via AIM to clovi_kate Send a message via MSN to clovi_kate Send a message via Yahoo to clovi_kate
I have a question about class h amps having a mosfets switch. At time when amp is at full state (maximum operation), does the voltage across drain to source of mosfet reaches zero? (Vds=0)?.. And when the mosfets starts to switch to the HIGH voltage, does it increase the voltage slowly or it will switch to its highest voltage right away?..
__________________
  Reply With Quote
Old 21st December 2011, 01:08 AM   #3
ontoaba is offline ontoaba  Indonesia
diyAudio Member
 
ontoaba's Avatar
 
Join Date: Nov 2009
Location: Kudus, Malang, Dieng
There are some differences when the mosfet turned on. The simplest one the mosfet just switched on when comparator say "go", and amplifier supply voltage increasing to the higher rail as fast as possible. The other one, there is a slew limiter so the voltage increases with limited speed/slew. Some other with early switch on and off with slew limiter.

Mosfet has its Rds-on when turned on, so there will be small drop voltages, around 1 volt.
  Reply With Quote
Old 21st December 2011, 02:21 AM   #4
diyAudio Member
 
Join Date: Jan 2006
Location: Visayas Region
Send a message via AIM to clovi_kate Send a message via MSN to clovi_kate Send a message via Yahoo to clovi_kate
shal we say we have a rail of +-55V and +-110v and uses 15v early before the mosfet switch on. if the output voltage reaches shall we say 46Vp, mosfet will go 'on' and Vds has a voltage not equal to 1V. (with the pinch off voltage considered 4v)

so WHAT IF in this condition the 2 mosfets (+ and - rail switch) did not fire equally, resulting +Vrail and -Vrail shall we say +65v and -75v. does this condition will affect the dc offset of the amplifier because unbalanced rails?..
__________________
  Reply With Quote
Old 21st December 2011, 02:50 AM   #5
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
"does this condition will affect the dc offset of the amplifier because unbalanced rails?"

No.
__________________
Candidates for the Darwin Award should not read this author.
  Reply With Quote
Old 22nd December 2011, 09:31 AM   #6
ontoaba is offline ontoaba  Indonesia
diyAudio Member
 
ontoaba's Avatar
 
Join Date: Nov 2009
Location: Kudus, Malang, Dieng
Supply voltage only switched at output stage, and VAS always connected to highest rail, and opposite mosfet stay off when a rail switched.

This is a multi step classH with slew limiter and early on/off for high speed operation (around 10kHz). Also higher voltage margin for higher step, because OPS has more drop voltage when draw more current.
Attached Images
File Type: png classH 5step.PNG (13.1 KB, 79 views)
  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
margan : non switching class B sreten Solid State 16 22nd May 2011 05:43 PM
Class AB, Class AB Non-Switching, Class AB Soft Non-Switching steph_tsf Solid State 4 15th March 2010 04:39 PM
New class A biasing (with non-switching class AB overflow) Steven Solid State 34 24th March 2007 07:40 PM
switching class d amp steven344 Class D 10 20th November 2005 04:22 AM
Non-switching amp same as Class A? mjarve Solid State 2 26th June 2004 08:43 PM


New To Site? Need Help?

All times are GMT. The time now is 04:12 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