Hi,
I have changed the the operating mode to BD and the heating issue seems to have largely gone and the PA is taking a more sensible amount of current. However, my colleague Charles originally raised a point about the hissing noise coming from the amplifier, which is still there albeit to a much lesser degree. The PA is connected to a VLSI audio processor via I2S bus so I took a snap shot of the I2S traces whilst I could observe the noise from speakers.
Everything seems as it should be so I measured the output from the amplifier on the right channel so these traces are + & - between the output pin and the inductor. The red channel is the math channel.
There seems to be an offset between + & - traces so I am not sure if this could be causing the noise?
I also took a spectra of the acoustic noise...see below. It seems spread below 4kHz and kind of varies in intensity.
Any ideas welcome.
Dalibor
