TPA3118D2: PLIMIT 0V issue

Genadi Manoilenko

Part Number: TPA3118D2

Tool/software:

Hi TI.

I set the PLIMIT to 0V (shorted it to GND) while it (PLIMIT) is connected through a 51k oHm resistor to GVDD. I expected it will limit the Pmax to 0W (no sound) but it's still playing. Do you have any thoughts?
Best regards, Genadi

3 months ago

0 Sydney Northcutt 3 months ago

TI__Mastermind 18070 points

Hi Genadi,

Are you changing the PLIMIT voltage while the device is playing audio? I believe the MUTE pin is a better method to reaching your goal of turning off the output during operation.

Regards,
Sydney Northcutt

0 Genadi Manoilenko 3 months ago in reply to Sydney Northcutt

Prodigy 95 points

I have a low-quality speaker with poor documentation connected to the amplifier. The label says it can handle up to 30W, but I’m not confident in that. When using the maximum rated power, I hear some distortion or noise. To limit the power, I connected a potentiometer in place of R82 to find an optimal resistance value. This helped me determine that the amplifier still outputs a signal under these conditions. That’s why I’m asking — is this expected behavior, or did I do something wrong?

0 Sydney Northcutt 3 months ago in reply to Genadi Manoilenko

TI__Mastermind 18070 points

Hi Genadi,

The issue may be that the PLIMIT is not set correctly based on the gain, load, input signal, etc. When playing various other signals, is the power limited to the expected value? You can reference this thread which has an excel calculator: https://e2e.ti.com/support/audio-group/audio/f/audio-forum/284968/how-to-caculate-the-power-limit-of-tpa3118-by-set-plimit.

Regards,
Sydney Northcutt

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TPA3118D2: PLIMIT 0V issue