Hi,
we have two possibly related issues with the TPA3255:
In our design - but not on TPA3255EVM or a "Cheap and cheerful" ready-made Amplifier -
we encounter dropouts at relatively low output power (~100W RMS into 4Ω) (whereas both the EVM and the cheap amp run fine at much larger power)
These dropouts do _not_ trip the protection circuit!
When we are in this state, disabling the amplifier leads to a latchup-like condition where power draw rises to ~1.5A for a short while, this puts out a LOT of heat.
This was much worse in a previous design iteration (~50W RMS into 4Ω).
Power supply is 48V regulated, differential input signals are used, we're running in Stereo BTL mode.
Filter Inductors are the same PN as on the -EVM, capacitors are the WIMA MKP equivalents, rest of the circuit is as on the -EVM
Additionallly, with the newer design Iteration (with the Layout much more close to the -EVM), we encounter a ~50kHz common mode oscillation (in-phase between OUTA/OUTB resp OUTC/OUT): (Current measurement in the filter inductors)
We checked out inputs directly at the IC, they're clean.
If you need any Schematic or Layout excerpts, i'm happy to provide them
Greetings, Martin
