Of course RMS voltage and current are 0.707 of peak and as power is V x I then 0.707 x 0.707 or approx 0.5. To be pedantic of course RMS VOLTS X RMS AMPS = Average Power.
What everyone including me is forgetting is that this amp will go seriously loud. Although of course that depends on the efficiency of the speakers and ........
What everyone including me is forgetting is that this amp will go seriously loud. Although of course that depends on the efficiency of the speakers and ........
I built up the pcb then realised I had doubled up the power tracks which means I need twice as thick pcb tracks so I wont get 1000 watts into 2 ohms now just 400 watts.
And 800 watts bridged.
I asked my pcb supplier what the copper ounces per square foot is and he said it was 1 ounce per square foot. This means max current can be 10 amps or if a sine wave is applied 14.414 amps average.
And 800 watts bridged.
I asked my pcb supplier what the copper ounces per square foot is and he said it was 1 ounce per square foot. This means max current can be 10 amps or if a sine wave is applied 14.414 amps average.
D
Deleted member 148505
You should have provided solder stop mask so that you can fill the traces with soldering lead or put a solid wire on it
The pcb is solder masked. I guess I could scrape it off but sounds like a pain.
Its not just the mosfet connections but the power supply tracks that are too thin.
I will just make a 400w + 400w pcb and use that.
Built up my first pcb and neither channel worked.
The phase splitter for bridge mode was killing the VAA and VSS supplies.
I reduced the dropper resistor from B+ and B- and that fixed that problem.
With 2 channels using the same VCC supply I was getting dropout on the VCC.
There were sharp pulses on VCC. To fix this I put an electrolytic on the input to the regulator and this fixed that.
Both channels burst into life but channel 2 was very noisy.
I checked the ground line and this went all through the output mosfet circuit before it got back to smoothed ground. I put in a link to short circuit the ground and the noise went away.
So in my rush to get the pcb made I made a few mistakes.
I guess if it worked first time I wouldnt have learned anything.
The phase splitter for bridge mode was killing the VAA and VSS supplies.
I reduced the dropper resistor from B+ and B- and that fixed that problem.
With 2 channels using the same VCC supply I was getting dropout on the VCC.
There were sharp pulses on VCC. To fix this I put an electrolytic on the input to the regulator and this fixed that.
Both channels burst into life but channel 2 was very noisy.
I checked the ground line and this went all through the output mosfet circuit before it got back to smoothed ground. I put in a link to short circuit the ground and the noise went away.
So in my rush to get the pcb made I made a few mistakes.
I guess if it worked first time I wouldnt have learned anything.
I had some problems on a previous irs2092 design so learned a bit from that.
This time I think I just rushed things a bit.
Built up another pcb as I couldn't get one channel on the first one working.
Both channels work now but I had trouble with background noise.
This was tracked down to the VCC 12 volt regulator not being decoupled well enough.
I found I needed 100uf and 220nf on the input to the regulator.
I also put a 220nf close to the regulator output.
I fixed the phase splitter power supply with lower value dropper resistors and 6 volt zeners.
Both channels work now but I had trouble with background noise.
This was tracked down to the VCC 12 volt regulator not being decoupled well enough.
I found I needed 100uf and 220nf on the input to the regulator.
I also put a 220nf close to the regulator output.
I fixed the phase splitter power supply with lower value dropper resistors and 6 volt zeners.
This is my working pcb after bodging it to get it to work.
I did try to get the grounds starred but I missed a couple of places.
The VS feedback capacitors went to a dirty ground instead of audio ground and this injected noise into audio signal.
VCC was dirty and required more decoupling both on regulator and at the 2092.
The mosfet decoupling was terrible as the capacitors didn't connect near enough to the mosfets to do any good. The red wires link the decoupling closer to the mosfet.
I did try to get the grounds starred but I missed a couple of places.
The VS feedback capacitors went to a dirty ground instead of audio ground and this injected noise into audio signal.
VCC was dirty and required more decoupling both on regulator and at the 2092.
The mosfet decoupling was terrible as the capacitors didn't connect near enough to the mosfets to do any good. The red wires link the decoupling closer to the mosfet.
An externally hosted image should be here but it was not working when we last tested it.
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Please explain , so most of us can learn something here ,
Nigel does seems to know quite a bit about the irs2092 and I always enjoy and learn reading his experiments and experience with this wonderful chip .
Would be nicer to give some positive advice rather then your four word negative reply .
Rens
Go and download IRAUDAMP7s and IRAUDAMP9 reference designs, along with the design papers for Class D layout and the IRS2092 from the IR website. Study them and they will pretty much tell you all you need to know. Problems with this design?
Through-hole parts
Miles of space between various sections
No shotgun routing of the gate signals from the IRS2092
Poor snubber placement
MOSFETS over here, output filters over there, bus supply caps over there at the end of the board
No copper planes for input section tied to signal GND, switching stages tied to -B, output filter and loudspeaker high current nodes
Etc., etc., etc.
Through-hole parts
Miles of space between various sections
No shotgun routing of the gate signals from the IRS2092
Poor snubber placement
MOSFETS over here, output filters over there, bus supply caps over there at the end of the board
No copper planes for input section tied to signal GND, switching stages tied to -B, output filter and loudspeaker high current nodes
Etc., etc., etc.
Know all about the designs ,
You didn't get the message and it was not addressed to you but to SNY.
This is not how you reply on a DIY forum . Sorry you did not get the message !
Cheers ,
Rens
Ummm...this is an open forum and anyone is free to respond.
As you yourself have said, you read and learn from these designs. I think that it's helpful to point out issues to everyone reading these forums so that they don't make the same mistakes...
As you yourself have said, you read and learn from these designs. I think that it's helpful to point out issues to everyone reading these forums so that they don't make the same mistakes...
OK we are DIY'rs and not Diplomats . English , used on this forum , is not the first language to many of us ( including myself ) BUT , SNY is rude and you could have read some more posts of Nigel , to see that he's been already there (your references to the reference design)
Have a good one !
Cheers ,
Rens
I reworked the decoupling and I can get both channels working without resetting into an 8 ohm load.
So I started looking at bridged mode which keeps resetting at higher power levels.
I looked at the filter output and was getting 55KHZ sine wave output with the inputs shorted !
The only change I had made was changing mosfet gate resistors to 4r7 from 10r on channel 1.
So I put back the 10R's and the 55KHz went away.
I wont even pretend to understand why !
Its midnight here now so cant test the bridge mode for resetting so will have a go tomorrow.
So I started looking at bridged mode which keeps resetting at higher power levels.
I looked at the filter output and was getting 55KHZ sine wave output with the inputs shorted !
The only change I had made was changing mosfet gate resistors to 4r7 from 10r on channel 1.
So I put back the 10R's and the 55KHz went away.
I wont even pretend to understand why !
Its midnight here now so cant test the bridge mode for resetting so will have a go tomorrow.
lol like I don't know that !
The feedback capacitors were actually right according iraudamp7 pcb layout so I have taken off the links and put them back.
The mosfet decoupling capacitors are in the right place just the tracks to them go the wrong way.
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