Class D schematic and PCB

[pompeiisneaks]

I haven't updated the schematic yet, but the vcc came from my bench power supply, I connected the - to the B- and the 12VDC+ to the connection at pin12. The mosfets I used were 100V 50A STP40NF10 from mouser here: https://www.mouser.com/QuickViewProdDet ... kView=true Everything else is pretty much the same. B+/B- of 48VDC+/- 12VDC at VCC with - at B-.

so even if it starts at -48VDC instead of -35VDC it will still be ~5VDC range? Why was I measuring 9VDC then? I'm using the 8.2k 1.2k as the schematic denotes. Could that have been due to the failure of the device itself sending 9v from somewhere else through the burned IC?

~Phil

[pompeiisneaks]

Here's the updated schematic, with the new voltages and fets

ClassDRev1.png

~Phil

[pompeiisneaks]

I also got some help on both EEVBlog and diyaudio, I'm following up there, but figured I'd share here.

One thing that was noted is there are two reference schematics, in one there's a 150pF cap to ground on the NFB line, mine didn't have that, and it might be to tame oscillations that might have been what killed the chip.

I'm attaching that revision here for information.

TypAppDiag.png

~Phil

[Gainzilla]

Hey, late to the party, but what sort of performance do you expect to get out of this circuit?

[pompeiisneaks]

Well first off it didn't work... I tried building it in a more tube amp friendly way on a piece of garolite and it immediately smoked the chip. I went to a class-d specific subforum of I think diyaudio.com and was castigated as a heathen.

Sounds like for Class D in these setups you need to do it on pcb with things extremely small and close to one another as parasitic oscillations can cause severe mayhem. So I gave up for now

I haven't revisited it since.

~Phil