TPA3255-Q1: Overload when output power is only ~40W

Hi Pham

   For PBTL using, may not support single end using, better send in differential signal between inputA and inputB. Otherwise the output may not as expected. Could you please use oscilloscope to capture the output waveform? It's possibly has some DC voltage according to your using.

Hi Shadow, 
Thank for your reply
I tried as your comment, at A and inB are differential signals, at this input I increase to 1.3V (2.6Vpp), the output is still off, the capacity is about 108W (16V3A)
Is this problem normal?
I don't notice any DC voltage between the two load terminals

I'm not a TI expert on this part but it looks like you have 12V on the VDD and GVDD pins.  I think the TPA3255-Q1 datasheet max is 11.4V  The standard TPA3255 can use 12V

yeah, i tried with 10.6V power supply but the problem is still

Hi Pham

  Please set DC coupling of the oscilloscope to capture the waveform. And are able to test the current through the inductor? Better to capture the point when the Fault happens.