Hi Bender !
I'am very interested about this http://www.diyaudio.com/forums/attachment.php?s=&postid=1189672&stamp=1177142837
Can you post scematic and PCB layout in (*.lay) format? It is very interesting to look it.
I'am very interested about this http://www.diyaudio.com/forums/attachment.php?s=&postid=1189672&stamp=1177142837
Can you post scematic and PCB layout in (*.lay) format? It is very interesting to look it.
IVX said:
Hi IVX!
I mean about lastest version of amp (with four fets in output stage). I can't find it
Dr.Gradus said:
Hi IVX!
I mean about lastest version of amp (with four fets in output stage). I can't find it
Yes Yes. Bender , Please...
An externally hosted image should be here but it was not working when we last tested it.
Hi all.
Hi Paul 😉 (Dr.Gradus), nice to see you. What about your project?
I haven't schematics, keep it in my mind
, i'll draw and post it later. PCB..hmm, i didn't finished it yet, only proto, so there can be some mistakes.
Guys, what are you talking about???
Take a look outside the window... summmer, girls
, beer 
(or hotter) 
.. love is in the air. Do you really wanna sit at home and design damps? i don't shure
Hi Paul 😉 (Dr.Gradus), nice to see you. What about your project?
I haven't schematics, keep it in my mind
, i'll draw and post it later. PCB..hmm, i didn't finished it yet, only proto, so there can be some mistakes.Guys, what are you talking about???
Take a look outside the window... summmer, girls
, beer (or hotter) .. love is in the air. Do you really wanna sit at home and design damps? i don't shure
Hi Oleg!!! I'am very glad to see you too 🙂 !!!
I dont finished my amp 😀 . I make many PCB's for this, but, did not get find good result.
My lastest gesign look better. Later i test it in work.
I use same schematics. But i change tranzistors in driver.
Now i use bcp807/817. It isn't take very hot even with gate resistor 2,5 ohm! Fets is IRF540. Thanks IVX for hint 😉 .
ÂÑP53/56 is realy too big for this.
Oh! I want ask! How did you calculate output filter?
I have carrier frequency 150kHz. R(load)=0,5 ohm. Power is near +- 35 V. How i can calculate inductor and capaicator of output filter?
I mean that my 0.2 mHn is very big inductance for this.
I dont finished my amp 😀 . I make many PCB's for this, but, did not get find good result.
My lastest gesign look better. Later i test it in work.
I use same schematics. But i change tranzistors in driver.
Now i use bcp807/817. It isn't take very hot even with gate resistor 2,5 ohm! Fets is IRF540. Thanks IVX for hint 😉 .
ÂÑP53/56 is realy too big for this.
Oh! I want ask! How did you calculate output filter?
I have carrier frequency 150kHz. R(load)=0,5 ohm. Power is near +- 35 V. How i can calculate inductor and capaicator of output filter?
I mean that my 0.2 mHn is very big inductance for this.
Hi IVX.
I used 5 ohm gate resistor for each fet. 2.5 ohm is just for experiment.
Can you say what bad in value 5 ohm for each fet?
I used 5 ohm gate resistor for each fet. 2.5 ohm is just for experiment.
Can you say what bad in value 5 ohm for each fet?
Dr.Gradus said:
Less gate res = more dV/dt, it's not always good regarding EMI, and reliability.
If i remember correctly, you use ir2104 at 100khz, so you'll happy with 10-20ohm indeed. Actually single irf540z isn't so heavy for dis/charging, and ir2104 would be ok without BJT's even, though with the BJT, ir2104 will have much better chance be alive after mosfets blew up.
Yes. Now I use IRF540 vs 150 kHz carrier. But IRF540 just for practice. In real project of car amplifier i plane to use IRFBA90N20D of something like this. Thats why I experiment vs 5 ohm gate resistor.
IVX, can you say how I can calculate output filter for D-amp (not UcD, just vs simple trigrane mod, prefilter feedback )?
F=150kHz R(load)=0,5..1ohm.
I mean that my 200 mkHn it realy big value for this. Output current of amp is nearly 60A in peak, i can't find good solution for 60a/200mKhn inductor. 50 mkhn/60A is realy easy, but i didn't now can i use this value (50 mkHn) for my amp.
Thanks.
IVX, can you say how I can calculate output filter for D-amp (not UcD, just vs simple trigrane mod, prefilter feedback )?
F=150kHz R(load)=0,5..1ohm.
I mean that my 200 mkHn it realy big value for this. Output current of amp is nearly 60A in peak, i can't find good solution for 60a/200mKhn inductor. 50 mkhn/60A is realy easy, but i didn't now can i use this value (50 mkHn) for my amp.
Thanks.
how much residual switching at the output, you want to achieve? Also, probably you could be happy with two output LC. BTW, my old class D project (2002) had 80uH+1uF (+/- 50VDC, 2Ohm load) and 100kHz switching, so it's about 2-3VRMS residual switching, that's no problem for subwoofer.
OK. Thanks!!! 80mKhn is realy easy for current 60A.
And I have to you two small questions about feedback.
I'am attached scematic of my prefilter feedback.
- At what frequency i need frequency cut of feedback?
- And what order of filter (R3 C3 R2 C2) i needed for good work of amp? Can i doing third order filter in the feedback, or it is offendig?
My power is +-50 V if it it have somethig importance...
And I have to you two small questions about feedback.
I'am attached scematic of my prefilter feedback.
- At what frequency i need frequency cut of feedback?
- And what order of filter (R3 C3 R2 C2) i needed for good work of amp? Can i doing third order filter in the feedback, or it is offendig?
My power is +-50 V if it it have somethig importance...
Attachments
Better for your application to take feedback after output coil and manage it as linear power amp...Better damping for your amp...
Fredos
Fredos
Hi Fredos.
I try to doing my amp with post filter feedback, but near clipping appeared problems - apprared high frequency noises in tweeter. With prefilter feedback my amp work better (no strange noises near clipping). Maybe my problem in bad value inductor of cap in output filter.
Can you say what value of residual switching i need for organize post filter feedback for reability working of amp.
Thanks 😉
I try to doing my amp with post filter feedback, but near clipping appeared problems - apprared high frequency noises in tweeter.
With prefilter feedback my amp work better (no strange noises near clipping). Maybe my problem in bad value inductor of cap in output filter.Can you say what value of residual switching i need for organize post filter feedback for reability working of amp.
Thanks 😉
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