New Class D design

peranders · 7th October 2007, 10:12 AM

Anybody who have checkec this out?
http://www.irf.com/technical-info/re.../iraudamp4.pdf

phase_accurate · 8th October 2007, 07:40 AM

Old-fashioned non-post-filter NFB type amplifier.

Regards

Charles

IVX · 8th October 2007, 08:13 AM

Quote:

Originally posted by peranders
Anybody who have checkec this out?
http://www.irf.com/technical-info/re.../iraudamp4.pdf

now the new is http://www.irf.com/technical-info/re.../iraudamp5.pdf

phase_accurate · 8th October 2007, 12:18 PM

Ahhhhh ! There is even a newer boring design without post-filter NFB !

Regards

Charles

Eva · 8th October 2007, 06:35 PM

Hey, but look at the schematics, they have migrated to a phase-shifted self oscillating arrangement, in such a way that modifying it for post-filter feedback is trivial.

What they have done at IR is essentially a single-chip UcD solution

It only lacks the balanced inputs...

phase_accurate · 9th October 2007, 06:41 AM

Quote:

in such a way that modifying it for post-filter feedback is trivial.

http://www.diyaudio.com/forums/showt...789#post825789

Regards

Charles

Ouroboros · 9th October 2007, 07:18 AM

I've been looking at the IRS2092 data (as published so far) to see if it could be used to implement a UCD-style circuit. The input op-amp is internally coupled to the comparator stage, which is unfortunate, but the input op-amp is a transconductance amplifier, so it might just be possible to couple in the feedback to the op-amp/comparator junction to get a phase-shift 'UCD' style self-oscillator.

I've got a chap coming in to see me from 'Future Electronics' (A big UK distributor) tomorrow about this chip, so I'll try to scrounge a few parts to try it out.

IVX · 9th October 2007, 07:44 AM

Ouroboros, i've a doubts about such solution:
A) it seems ir ref. designs hasn't good precision of switching.
B) internal comparator isn't differential.

Ouroboros · 9th October 2007, 07:51 AM

Hello Ivan. Yes the fact that the comparator isn't differential is an issue. I've not had the time to study the chip yet, but at a glance it seems that to apply UCD style feedback directly into the input of the comparator would require that the feedback went to the + input of the comparator (which isn't accessible).

7th October 2007, 10:12 AM	#1
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	New Class D design Anybody who have checkec this out? http://www.irf.com/technical-info/re.../iraudamp4.pdf __________________ /Per-Anders (my first name) or P-A as my friends call me

8th October 2007, 06:35 PM	#5
Eva diyAudio Member Join Date: Oct 2003 Location: Near the sea	Hey, but look at the schematics, they have migrated to a phase-shifted self oscillating arrangement, in such a way that modifying it for post-filter feedback is trivial. What they have done at IR is essentially a single-chip UcD solution It only lacks the balanced inputs... __________________ I use to feel like the small child in The Emperor's New Clothes tale

9th October 2007, 07:44 AM	#8
IVX diyAudio Member Join Date: Jul 2003 Location: Everywhere (Buddhist's context)	Ouroboros, i've a doubts about such solution: A) it seems ir ref. designs hasn't good precision of switching. B) internal comparator isn't differential. __________________ Best regards, E1.

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8th October 2007, 07:40 AM	#2
phase_accurate diyAudio Member Join Date: May 2002 Location: Switzerland	Old-fashioned non-post-filter NFB type amplifier. Regards Charles

8th October 2007, 12:18 PM	#4
phase_accurate diyAudio Member Join Date: May 2002 Location: Switzerland	Ahhhhh ! There is even a newer boring design without post-filter NFB ! Regards Charles

9th October 2007, 07:18 AM	#7
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	I've been looking at the IRS2092 data (as published so far) to see if it could be used to implement a UCD-style circuit. The input op-amp is internally coupled to the comparator stage, which is unfortunate, but the input op-amp is a transconductance amplifier, so it might just be possible to couple in the feedback to the op-amp/comparator junction to get a phase-shift 'UCD' style self-oscillator. I've got a chap coming in to see me from 'Future Electronics' (A big UK distributor) tomorrow about this chip, so I'll try to scrounge a few parts to try it out.

9th October 2007, 07:51 AM	#9
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	Hello Ivan. Yes the fact that the comparator isn't differential is an issue. I've not had the time to study the chip yet, but at a glance it seems that to apply UCD style feedback directly into the input of the comparator would require that the feedback went to the + input of the comparator (which isn't accessible).

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