How to caculate the Power Limit of TPA3118 by set Plimit?

cg xie

Dear Sir,

I've just designed a board with TPA3118, and need to limit TPA3118 max output power to 10W. there is 2 quesitons for Table 3 in the page 17 of TPA3118 spec.

1. Does the max output power = Vrms * Vrms / Rload?

For example, in the last row of Table 3, Pmax= 6.3*6.3/4 =10W ( for a 4 OHM load)? Is this right?

2. Is the max output voltage only decided by the Plimit voltage or related with gain value and input signal voltage?

Thanks a lot.

over 12 years ago

0 Arnold Zhang over 12 years ago

TI__Intellectual 1050 points

Hello cg,

Here is an Excel sheet Paul created with a way to derive PLIMIT's voltage effect on output waveform. Gain and input signal voltage also serve as factors, as the formula shows. Lowering the PLIMIT will, depending on values, start attenuating your output peaks.

2570.Gilbert-tpa3113d2-Plimit-calcs.xls

Here is an example plot. The TPA31XX devices have basically the same PLIMIT functionality.

Best regards,
Arnold Zhang

0 cg xie over 12 years ago in reply to Arnold Zhang

Intellectual 260 points

Thanks a lot.

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How to caculate the Power Limit of TPA3118 by set Plimit?