Part Number: TPA3255
We're using the TPA3255 in PBTL mode to drive 250W+ into a transformer isolated load (after the filters). We're seeing ~20mV of DC offset at the output with a 48V VCC. With as low as the DC resistance of the transformer primary is, this actually corresponds to a fair amount of current, and is cutting into our saturation margin.
With 12A RMS as an option, it takes a whole lot of parallel capacitors to get both a 100 Hz AC corner and enough ripple current rating to not explode. It feels like we'd be better off sensing the offset with a diffamp and servoing it out at the input; we could easily close that loop with a 1 Hz corner. But there's no information on the DC path in the datasheet; the assumption is AC-coupling caps and you walk away.
Is there a DC path through the part? What do the device inputs look like at DC?
