TAS2563: Limiter Not Working on Sine Waves

Oren Rappoport

Part Number: TAS2563

Hi Ivan,

We found that the limiter apparently doesn't work with sine waves but seems to be effective with white noise and with music. This behavior results in the amplifier exceeding its power budget by a wide margin, even with the boost converter completely disabled. Please review the screen shots below from EVB measurements and advise how to hard limit the output levels regardless of audio content.

Thanks, O.R.

Amplifier output with FS white noise:

Amplifier output with a FS 500 Hz sine wave:

Limiter settings:

over 3 years ago

0 Ivan Salazar over 3 years ago

TI__Guru** 110745 points

Hi Oren,

I'll double check this feature, perhaps there are other settings that need to be adjusted.

Best regards,
-Ivan Salazar
Applications Engineer

0 Ivan Salazar over 3 years ago in reply to Ivan Salazar

TI__Guru** 110745 points

Hi Oren,

I have confirmed the correct operation of the limiter both for sine wave and white noise. I think your captures are also correct.
Please notice that limiter is set for V-peak, not V-peak-to-peak.

Best regards,
-Ivan Salazar
Applications Engineer

0 Oren Rappoport over 3 years ago in reply to Ivan Salazar

Intellectual 340 points

Hi Ivan,

Re: Please notice that limiter is set for V-peak, not V-peak-to-peak.

Do you mean that the limiter is set incorrectly?

Thanks, O.R.

0 Ivan Salazar over 3 years ago in reply to Oren Rappoport

TI__Guru** 110745 points

Hi Oren,

What I mean is that, from the PPC3 capture, the limiter is set to 4V-peak, that means your output signal will go from 4V to -4V amplitude.

Best regards,
-Ivan Salazar
Applications Engineer

0 Oren Rappoport over 3 years ago in reply to Ivan Salazar

Intellectual 340 points

Hi Ivan,

I changed the limiter setting to 1.5 V expecting to see a 3 Vpp output level but it's actually over 5 Vpp. I'm also getting a slightly higher output with FS white noise than I got on Friday and changing the limiter setting back to 4 V didn't affect this result. I used the same PPC3 file as my previous test. Is there another setting interaction that is affecting the limiter behavior and thus the output levels?

Thanks, O.R.

Amplifier output with a FS 500 Hz sine wave:

Amplifier output with FS white noise:

Limiter settings:

0 Ivan Salazar over 3 years ago in reply to Oren Rappoport

TI__Guru** 110745 points

Hi Oren,

It seems the limiter can go as low as ~2.2Vpk. although your capture seems a bit higher than that.

If you want to evaluate the features on Device Control panel I would suggest to use ROM mode, otherwise the processing features of tuning mode can affect the measurements.

Best regards,
-Ivan Salazar
Applications Engineer

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TAS2563: Limiter Not Working on Sine Waves