Question: I am using the TPA6140A2 for the headphone amplifier in my new handheld device design and it occurred to me, would it clip if it received a large amplitude signal while the Class-G was running at 1.3V.
Answer: The short answer is no. If a large amplitude signal was received while the Class-G was running at 1.3V, the Class-G would simply increase HPVDD (and HPVSS) to 1.8V to accomodate it. To further illustrate the effect of a large signal, I ran a test where I set-up the input signal and gain to be very close to the threshold where the Class-G changes from 1.3V to 1.8V. Since there is ample headroom in the input circuitry, no clipping occurs.
I have attached a presentation that explains the testing that I did in more detail.
Regards,
Fred