Hi,
I came across this issue when using LM48100Q for a speaker application. I'm using only one of the LM48100Q inputs(it has two) and the load connected to the amplifier is an 8 ohm speaker. I see that the output is a bridge tied load which means it's differential and not single ended. Also the amplifier outputs are both biased about V DD /2, so eliminating any net DC voltage across the load. The amplifier IC has a feature for fault detection by which it can detect the following:
- Output Short to Supplies (V DD or GND)
- Output Short Circuit and Open Circuit Detection
- Output Over-Current Detection
- Thermal Overload Detection
This fault detection is done as a part of the continuous diagnostics feature of the IC. When in this mode, the speaker starts to vibrate feebly and it feels weird. Also I observed that when this feature is enabled, the IC is sending on the output lines, a pulse of frequency 81 Hz with Vmax of V DD, the pulse on width is 40 us. Is this done as a part of any impedance measurement by the IC? Any insights on this would be helpful.
Thanks.
Regards,
Sravan Mohan
