Q: Quick Reference guide to Max output power of a Class D amplifier

Can you comment on a Class D's max output power for a given power supply and load?

 


A: Re: TAS5613 - max output power from 24V to 4ohm load?

Hi,

The pdf file attached at the end of this post shows how to approximate the max output power for a Class D at a given PVDD and load. It uses the TAS5613 as an example with PVDD = 24V and a 4 ohm load.

What the file shows is that the RDSON of the device creates a voltage divider with the load. It shows that the largest unclipped sine wave will have about 65W and a clipped signal (10% THD) will be 81.6. Note that the calculation of 10% THD is an approximation that says P_clipped = 1.25* P_unclipped.

If RdsOn were 0 ohm resistance (ideal output stage), the power would be 72W unclipped and 90W clipped.

2474.TAS5613 Max Power.pdf