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TPA3245: Relationship between PVDD and output power

Part Number: TPA3245

Hi TI experts,

My customer asked if it is possible to output 80W on PVDD 24V at load 8ohm. I think it is impossible to calculate.

Using the formula below, it need at least 25.3V for 80W.

P=VI=V*V/R, 80W = V*V*8ohm -> V=25.3V

In case of PVDD 24V, is there a way to output power over 80W? (Speaker Load 8ohm)

Thanks,

Downey Kim.

• Hi Downey,

When considering how much output power can be delivered at a specific PVDD, we usually use sine wave to do the calculation.

The relationship is, without voltage clipping, the max output power = Vrms^2/R = PVDD^2/2/R; where R is the loading resistance. The "/2" divider comes from the RMS level = 1/sqrt(2) * peak level.

Thanks!

Regards,

Sam

• Hi Sam,

So, your answer is that 80W output is not possible?

Thanks

Downey Kim.

• Hi Kim,

The answer is when you are using 24V PVDD and 8R loading, you can't achieve 80W without voltage clipping,

To achieve 80W, you can increase the PVDD or using lower resistance loading.

Regards,

Sam