ucd 25 watts to 1200 watts using 2 mosfets - Page 171

CPX · 04:10 PM

Dzony988 ..you shoud have no bus pumping in bridge mode.

Unfortunately No One makes real tests..i asked several times for some distorsions tests in vain...

Also i am interesested how you have implemented your protection schemes..the amplifier has to survire a short to output or rails, also over power in hard clipping,excesive bus pumping at 10-20hz and very high currents(>20A) ...simply sensing peak currents is not enough.

stewin · 29th February 2012, 05:16 PM

hi cpx .what can be done to avoid bus pumping and the above?

CPX · 29th February 2012, 05:34 PM

Alot can be done..and i am still doing experiments.

I have around 10-15 volts bus pumping at 20 hz so probably this in not the reason my fets burn at 25A,but reducing capacitance from 10mF to 5 mf makes them burn at only 8A rms,so bus pumping may not be the problem...increasing capacitance to 15mf and adding a high pass filter will probaly solve this...

Hard clipping is another story..when hard clipped before peak current the peak current protecion will not work since is not measuring rms.A rms to voltage should be used but the conversion is to slow for efective protection so i will try implement an aditional rms current protection.

Also a clipping current limitator can be implemented but that will not save the amplifier if it is fed with a square wave.

Dimonis · 29th February 2012, 06:01 PM

Quote:

Originally Posted by Dzony988

Only problem with full bridge is very high current and bus punping.

You mean pumping ?
In full bridge there"s no bus pumping

CPX · 29th February 2012, 06:08 PM

Quote:

Originally Posted by Dimonis

You mean pumping ?
In full bridge there"s no bus pumping

It may be if the bridge is unbalanced by using different switching frequencies between amplifiers creating unequal gain,but should be negligible .. 1 or 2 volts.

Dimonis · 29th February 2012, 06:40 PM

CPX
Agree with you.
But that"s not a good bridge

And i doubt about switching freq.

CPX · 29th February 2012, 06:57 PM

Quote:

Originally Posted by Dimonis

CPX
Agree with you.
But that"s not a good bridge

And i doubt about switching freq.

In mixed mode operation(stereo - bridge) you need to have different switching speeds and gains.

Dimonis · 29th February 2012, 07:37 PM

Ok. I understood about switching frequences , but why must the gains differ?

CPX · 29th February 2012, 07:42 PM

Different switching speeds generate diferences in gain also in this ucd..i was unable to change gain and switching frequency indepenend on each other.

irvynejay · 1st March 2012, 06:54 AM

Hello can i ask some newbie question could i use this mosfet on class d amp
IXFX30N100Q2 and IXFH15N80

29th February 2012, 03:54 PM	#1701
CPX diyAudio Member Join Date: Nov 2004 Location: Cluj	Dzony988 ..you shoud have no bus pumping in bridge mode. Unfortunately No One makes real tests..i asked several times for some distorsions tests in vain... Also i am interesested how you have implemented your protection schemes..the amplifier has to survire a short to output or rails, also over power in hard clipping,excesive bus pumping at 10-20hz and very high currents(>20A) ...simply sensing peak currents is not enough. Last edited by CPX; 29th February 2012 at 04:10 PM.

1st March 2012, 06:54 AM	#1710
irvynejay diyAudio Member Join Date: Nov 2010 Location: Philippines;Mindanao,Butuan	Hello can i ask some newbie question could i use this mosfet on class d amp IXFX30N100Q2 *and IXFH15N80* __________________ Knowing GOD is not being good,Knowing GOD is just knowing him as my friend

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
Philips 40/25/15 watts amplifier with Universal preamplifier circuit.	renjiish	Solid State	44	3rd April 2013 02:57 PM
Decibel Watts VS Watts ?	fivestring	Solid State	11	1st April 2009 01:08 PM
AMP1-B: why only 25 watts @8ohms?	theAnonymous1	Class D	10	15th August 2005 06:55 PM
Sound quality of amps at 0.3 watts vs @ typical 5 watts	rick57	Solid State	2	26th March 2005 06:25 AM
Need 2 watts	Vivek	Everything Else	4	17th July 2003 08:29 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

29th February 2012, 05:16 PM	#1702
stewin diyAudio Member Join Date: Jul 2007	hi cpx .what can be done to avoid bus pumping and the above?

29th February 2012, 05:34 PM	#1703
CPX diyAudio Member Join Date: Nov 2004 Location: Cluj	Alot can be done..and i am still doing experiments. I have around 10-15 volts bus pumping at 20 hz so probably this in not the reason my fets burn at 25A,but reducing capacitance from 10mF to 5 mf makes them burn at only 8A rms,so bus pumping may not be the problem...increasing capacitance to 15mf and adding a high pass filter will probaly solve this... Hard clipping is another story..when hard clipped before peak current the peak current protecion will not work since is not measuring rms.A rms to voltage should be used but the conversion is to slow for efective protection so i will try implement an aditional rms current protection. Also a clipping current limitator can be implemented but that will not save the amplifier if it is fed with a square wave.

29th February 2012, 06:40 PM	#1706
Dimonis diyAudio Member Join Date: Mar 2011 Location: RF 33 Vladimir	*CPX* Agree with you. But that"s not a good bridge And i doubt about switching freq.

29th February 2012, 07:37 PM	#1708
Dimonis diyAudio Member Join Date: Mar 2011 Location: RF 33 Vladimir	Ok. I understood about switching frequences , but why must the gains differ?

29th February 2012, 07:42 PM	#1709
CPX diyAudio Member Join Date: Nov 2004 Location: Cluj	Different switching speeds generate diferences in gain also in this ucd..i was unable to change gain and switching frequency indepenend on each other.