The dreaded irs2092 clicking on output.

[nigelwright7557]

I took the application sheet circuit for my 2092 amp.
I built a few with no problems.

Now all of a sudden the last 3 I have built arent working properly.
The music works fine up until about 90% max volume then the sound breaks up with the 2092 resetting.

The circuit looks pretty sound to me.
I have tried adjusting OCSET and CSH to give max current but it doesnt make any difference. Added extra decoupling and tried larger electrolytics where they are used and no joy.

Even tried larger output coil and different filter components.


Any suggestions would be gratefully recieved.

[nigelwright7557]

I found the problem, I use irfb4227 mosfets and the 2092 wont drive hard them without clicking.

[elevator]

Originally Posted by nigelwright7557

... then the sound breaks up with the 2092 resetting.

Can you elaborate on this symptom?

[nigelwright7557]

Originally Posted by elevator

Can you elaborate on this symptom?

The irs2092 resets and you can here the music click in and out as it resets and starts again.

It looks like the mosfets werent switching on fast enough as the 2092 cant drive irfb4227's very well.
Tried a second pcb and that had the same problem and was fixed by adding tc4420 drivers.

I noticed that reducing the mosfet gate driver resistor that the problem wasnt quite as bad, again pointing to mosfet gate drive problems.

[nigelwright7557]

The pcb with problems are using a new batch of irfb4227's. Could be this batch are more capacitive on the gate.
Anyhow adding the buffer sorted it.

[luka]

that would be interesting to know, if there was difference between fets alone