Introducing NEZ

mastertech · 25th October 2005, 01:24 AM

Hi guys
this is NEZ , any suggestions on how it can be improved further
your input will be appreciated

cheers

powerbecker · 25th October 2005, 05:07 AM

Hi Mastertech,

what means "NEZ" ?

First I see this topology in "elektrotechnik, oktober 1983" (Dr. Harms, University Hannover) used for a 25 VA poweramp for +/-350V outputvoltage.

It is a simple circuit to generate high voltages with a minimum of highvoltage n-transitors (or fets).

From there i tried it some years later (as a A/B-amp for +/- 500V) and i find it suffers at high frequencys on a strong asymmetry which stem from the capacitys of the bottom power/control-transistor/fet.

May be for a CLASS-A SPECIALIST and class-a biased and for smaller voltages it is useful!

:

So its good to use high ft-devices.
You can supply the base of the top-darlington from a current-source or bootstrap it.

Because its a transconductance-amp you need strong feedback to get a lo-impedance output so i think you had to add a 2. gainstage. (i used a op-amp)

To hold the voltage before the outputcap stable you need from there also a dc-feedback-path.

Good luck.
Regards

Heinz!

Steve Eddy · 25th October 2005, 05:10 AM

Quote:

Originally posted by powerbecker
what means "NEZ" ?

Not Exactly Zen?

Just a guess.

Oh! Duh. It's Zen spelled backward.

se

powerbecker · 25th October 2005, 06:24 AM

Quote:

Originally posted by Steve Eddy

Not Exactly Zen?

Just a guess.

Oh! Duh. It's Zen spelled backward.

se

Ha, thank you!

I search for Zen and find it (NP)!

Indeed, the Zen looks very similar, but he has a CONSTANT-currentsource in the top, the Nez-top-currentsource is steering by the bottom-currentsource!

Regards
Heinz!

mastertech · 25th October 2005, 08:15 AM

Mr powerbecker

what an honor to have a German Engineer critisise my design
all your suggestions will be put to good use, your expertise
is second to none so is German Engineering

thank you sir

tlf9999 · 25th October 2005, 03:15 PM

Quote:

Originally posted by powerbecker
Indeed, the Zen looks very similar, but he has a CONSTANT-currentsource in the top, the Nez-top-currentsource is steering by the bottom-currentsource!

Regards
Heinz!

the top of the Nez is a constant current source, loading the bottom common emitter for gain.

Ultima Thule · 25th October 2005, 03:30 PM

Hi George!

Funny circuit indeed!

Don't you want to connect your feedback resistor direct to Collector?

BTW, are those Darlington's in one package, if not you may want to add a resistor between base and emitter of output transistors, or so.

Cheers Michael

powerbecker · 25th October 2005, 09:34 PM

Hi Mastertech,

thank for Your kind words too much honor!

Regards
Heinz!

powerbecker · 25th October 2005, 09:54 PM

Quote:

Originally posted by tlf9999

the top of the Nez is a constant current source, loading the bottom common emitter for gain.

Hi tlf9999

this is true for Zen. Btw the bottom common emitter works also as a currentsource but not as a constant one.
The Nez consists of 2 currentsources like the Zen but in contrast to Zen none of them is constant. So you can get better efficiency.

Regards
Heinz!

mastertech · 26th October 2005, 01:09 AM

Hi guys wow the view count is heating up
micheal yes you could add resistors to darlington network if
the circuit is made up from regular transistors, thanks for
your kind suggestion, btw are you German Engineer we get
a lot of them in this thread thats why im asking

thank you all guys i plan to use all of your suggestions in future
versions of Nez

regards
George

25th October 2005, 05:07 AM	#2
powerbecker diyAudio Member Join Date: Dec 2004 Location: Berlin	Hi Mastertech, what means "NEZ" ? First I see this topology in "elektrotechnik, oktober 1983" (Dr. Harms, University Hannover) used for a 25 VA poweramp for +/-350V outputvoltage. It is a simple circuit to generate high voltages with a minimum of highvoltage n-transitors (or fets). From there i tried it some years later (as a A/B-amp for +/- 500V) and i find it suffers at high frequencys on a strong asymmetry which stem from the capacitys of the bottom power/control-transistor/fet. May be for a CLASS-A SPECIALIST and class-a biased and for smaller voltages it is useful!: So its good to use high ft-devices. You can supply the base of the top-darlington from a current-source or bootstrap it. Because its a transconductance-amp you need strong feedback to get a lo-impedance output so i think you had to add a 2. gainstage. (i used a op-amp) To hold the voltage before the outputcap stable you need from there also a dc-feedback-path. Good luck. Regards Heinz!

25th October 2005, 03:30 PM	#7
Ultima Thule diyAudio Member Join Date: Jan 2004 Location: Koskenkorva Land	Hi George! Funny circuit indeed! Don't you want to connect your feedback resistor direct to Collector? BTW, are those Darlington's in one package, if not you may want to add a resistor between base and emitter of output transistors, or so. Cheers Michael __________________ "If transistors are blueberries and FETs are strawberries, then tubes must be.. pears" Michael 29th January 2010

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Introducing Myself - Greetings!	brucedog	Introductions	3	30th October 2007 03:59 AM
introducing...	lecky	Introductions	3	2nd May 2006 09:51 PM
Introducing Myself	C.Jackson	Introductions	3	19th April 2006 02:47 AM
Introducing ...	Jennifer	Introductions	1	27th January 2006 09:13 PM
Just introducing myself.	3beanlimit	Introductions	0	5th August 2001 04:23 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	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

25th October 2005, 08:15 AM	#5
mastertech Banned Join Date: Mar 2005 Location: Australia	Mr powerbecker what an honor to have a German Engineer critisise my design all your suggestions will be put to good use, your expertise is second to none so is German Engineering thank you sir

25th October 2005, 09:34 PM	#8
powerbecker diyAudio Member Join Date: Dec 2004 Location: Berlin	Hi Mastertech, thank for Your kind words too much honor! Regards Heinz!

26th October 2005, 01:09 AM	#10
mastertech Banned Join Date: Mar 2005 Location: Australia	Hi guys wow the view count is heating up micheal yes you could add resistors to darlington network if the circuit is made up from regular transistors, thanks for your kind suggestion, btw are you German Engineer we get a lot of them in this thread thats why im asking thank you all guys i plan to use all of your suggestions in future versions of Nez regards George