iraudamp9 problem!

[Dxvideo]

Hi all,

I am trying to build a iraudamp9 clone for subwoofer using..
So I implemented exactly the same circuit as;
http://www.google.com.tr/url?sa=t&r...wbHFBg&usg=AFQjCNGt6pqFAsgRBP2Vs_kz9kgbRgGPyg
Just the amplifier board (figure 24). And added (also tested) an auxilary 12v referenced to -V for Vcc. I have tested +/-5v onboard supplies and saw no problem.
However the amplifier did not start the PWM! Just a sawtooth (~2vpp, @4Khz) I saw on the output... And ~+16v DC offset!
By the way, my supplies are ~+/-45v and not regulated.
What do you think about that problem?
Thats a lof in advance for any kind of advice..

 

[fredos]

Feedback? Not included into duaghter board...

 

[Dxvideo]

Yes I already added a 120K resistor before the output coil to NINV input..

 

[savu]

You still need the 150pF cap and 1Kohm resistor. check page 27 of your PDF of iraudamp9

 

[Dxvideo]

Ok I will... But do you think its really important?

 

[Eva]

Feedback is needed for oscillation. It won't work without feedback. It's weird to notice feedback components missing from the schematic.

 

[herosungod]

my supplies are ~+/-45v and not regulated?
it this mean your suplies is the AC input?

 

[Dxvideo]

Of course no! ~ stands for appx..

 

[Dxvideo]

Anyway...
Feedback line modification works... Thanks..
But it oscillates @ 14-18Khz! Not more. I have tried a lot of combination for oscillator circuit (C21-C23-P1-R21 and according to AN1138) but nothing's changed!
Upper MOSFET works like 90% duty cycle while the lower one works like 10% everytime!
Now where am I mistaken?🙁

 

[herosungod]

have you make sure the critical component's value use in design in correct?
and try the bellow list in oscillating circuit,

 

[Dxvideo]

Yes they alll right. In first attempt the oscillator circuit was 1n+1k pot+470+1n. But after I saw 18Khz then they replaced with 2.2n+150R+2.2.. But nothing changed.

 

[herosungod]

Yes they alll right. In first attempt the oscillator circuit was 1n+1k pot+470+1n. But after I saw 18Khz then they replaced with 2.2n+150R+2.2.. But nothing changed.

I suggest change the 2092 !

 

[Dxvideo]

I already changed it one time. However my 2092 stock level is only 2 pcs...
Anyway, I think I will go with IR2110 1200W project..
But thanks a lot for your close interest.

 

[Hadighorbani]

HI guys
please share your pcb on site
thank you