Selfoscillating class D amplifier - Page 3

AP2 · 30th January 2010, 05:24 PM

hi,
I understand that can be used to test, but you lose your time, work all signals incorrect up to driver .
In theory at Bridge 2 Amp (+ /-100V) produce 2500W @ 8R.
I do not think is appropriate for first Class D amplifier.

vogor · 31st January 2010, 02:22 AM

Quote:

Originally Posted by AP2

hi,
I understand that can be used to test, but you lose your time, work all signals incorrect up to driver .
In theory at Bridge 2 Amp (+ /-100V) produce 2500W @ 8R.
I do not think is appropriate for first Class D amplifier.

Hi,

If to replace on D1 on ad817 then it will be much better, what else it is possible to improve in this circuit? By my approximate calculations in bridge inclusion should be 4000W@4R.

AP2 · 31st January 2010, 09:46 AM

hi,
I have only applied the formula to the theory of 200vp out.
3 parameters are needed for accurate power Out
load, rail voltage (power supply voltage decrease under current), and Vp on load
(Rail voltage - inefficiency of power out stage)
this for continuos power. (peak power is higher, becouse probable use big capacitors on voltage) this is measured with adequate burst signal on amplifier.

your scheme is too simple to support a very fast op-amp or comparator.
new circuit must be designed, including pre-driver solutions must be good.

vogor · 31st January 2010, 09:53 PM

Quote:

Originally Posted by AP2

your scheme is too simple to support a very fast op-amp or comparator.
new circuit must be designed, including pre-driver solutions must be good.

For me the main priorities of the given class it is efficiency, power, quality, by such principle I shall aspire to develop the given circuit. The prototype is conceived not for reception of very high parameters and for the first experiment, one watt on 4 ohms would suffice also. That you particularly could recommend to change in my circuit and that you mean under pre-driver solutions. Why you count not justified application of faster op-amp or comparator?

vogor · 1st February 2010, 04:54 AM

Quote:

Originally Posted by vogor

For me the main priorities of the given class it is efficiency, power, quality, by such principle I shall aspire to develop the given circuit. The prototype is conceived not for reception of very high parameters and for the first experiment, one watt on 4 ohms would suffice also. That you particularly could recommend to change in my circuit and that you mean under pre-driver solutions. Why you count not justified application of faster op-amp or comparator?

I wanted to tell 1KW on 4 ohms

Bender.ru · 07:47 AM

Hi, Vogor!

Maybe it will be better, if you start with something lighter & more simple, as you were advised early ?

Reactance · 01:56 PM

Hi all

This amp will work indeed, because its a circuit layout of a "irf example class-d amp application note" thats almost identical to the orignal ! i shall post the real deal on monday!

i was looking at this circuit just lastnight noticed the input stage that smelled familiar :-D

AP2 · 26th February 2010, 02:06 PM

Hi,
yes,works...
use fast comp instead di slow opamp,You can also improve pre-drive stage.this is critical for IMD-thd.

AP2 · 26th February 2010, 02:12 PM

ok, this is IRDAMP1... just to discourage listening.

vogor · 09:08 PM

Question: whether If to do a bridge exit and a unipolar power supply that it will be necessary levelshifter stage?

1st February 2010, 07:45 AM	#26
Bender.ru diyAudio Member Join Date: Jan 2007 Location: Krasnogorsk-city	Hi, Vogor! Maybe it will be better, if you start with something lighter & more simple, as you were advised early ? Last edited by Bender.ru; 1st February 2010 at 07:47 AM.

26th February 2010, 01:40 PM	#27
Reactance diyAudio Member Join Date: Jun 2005 Location: Cape Town	Hi all This amp will work indeed, because its a circuit layout of a "irf example class-d amp application note" thats almost identical to the orignal ! i shall post the real deal on monday! i was looking at this circuit just lastnight noticed the input stage that smelled familiar :-D __________________ There’s nothing worse than the smell of burned output transistors!! Last edited by Reactance; 26th February 2010 at 01:56 PM.

26th February 2010, 09:05 PM	#30
vogor diyAudio Member Join Date: Jun 2009 Location: Irkutsk	Question: whether If to do a bridge exit and a unipolar power supply that it will be necessary levelshifter stage? Last edited by vogor; 26th February 2010 at 09:08 PM.

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30th January 2010, 05:24 PM	#21
AP2 diyAudio Member Join Date: Dec 2009 Location: Italy	hi, I understand that can be used to test, but you lose your time, work all signals incorrect up to driver . In theory at Bridge 2 Amp (+ /-100V) produce 2500W @ 8R. I do not think is appropriate for first Class D amplifier.

31st January 2010, 09:46 AM	#23
AP2 diyAudio Member Join Date: Dec 2009 Location: Italy	hi, I have only applied the formula to the theory of 200vp out. 3 parameters are needed for accurate power Out load, rail voltage (power supply voltage decrease under current), and Vp on load (Rail voltage - inefficiency of power out stage) this for continuos power. (peak power is higher, becouse probable use big capacitors on voltage) this is measured with adequate burst signal on amplifier. your scheme is too simple to support a very fast op-amp or comparator. new circuit must be designed, including pre-driver solutions must be good.

26th February 2010, 02:06 PM	#28
AP2 diyAudio Member Join Date: Dec 2009 Location: Italy	Hi, yes,works... use fast comp instead di slow opamp,You can also improve pre-drive stage.this is critical for IMD-thd.

26th February 2010, 02:12 PM	#29
AP2 diyAudio Member Join Date: Dec 2009 Location: Italy	ok, this is IRDAMP1... just to discourage listening.

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