TAS5634: clipping

Vojtech Kana

Part Number: TAS5634

Hi all,

I have a question for you.

TAS5634DDV is sourced by 60 V. 1 kHz output signal. When voltage on output signal is above 90 V, then amplifier started clipping.

It means, that signal is over 1 % THD and that is the reason, why started clipping?

Or is it only information, that amplifier may be damaged?

Thank you for the answer.

Best regards,

Vojta

over 3 years ago

0 Sam(MPAA) Zhang over 3 years ago

TI__Mastermind 19080 points

Hi Vojta,

I suppose you were trying to say "When voltage on output signal is above 60 V, then amplifier started clipping. "

The output range of a class-d amplifier is 0~PVDD, which means if you are powering the device with 60V, the max peak voltage across the load will be 60V. If you try to push the output to higher level, it will just get clipped at PVDD.

Regards,

Sam

0 Vojtech Kana over 3 years ago in reply to Sam(MPAA) Zhang

Prodigy 190 points

Hi Sam,

My output connection is a PBTL bridge. 90 V is diferencial on load.

Sorry I missed this information.

Thanks for the answer.

Regards,

Vojta

0 Sam(MPAA) Zhang over 3 years ago in reply to Vojtech Kana

TI__Mastermind 19080 points

Hi Vojta,

90V is peak-peak amplitude, right? The differential voltage across the load is -PVDD to +PVDD.

You may use a oscilloscope to check the output waveforms on the output(after LC filter), and also the PVDD.

Regards,

Sam

0 Vojtech Kana over 3 years ago in reply to Sam(MPAA) Zhang

Prodigy 190 points

Hi Sam,

Yes, the output signal is 90 V peak - to peak. But TAS5634 is starting clipping with this value.

I want to know, what can cause clipping on TAS5634 in general.

If I supply TAS with 60 V, then should be some reserve on output (120 V p-p on output).

Output is 98 V p-p, measured on resistive load, 330 W. Outpu is a little bit limited.

Clipping started from 90 V p-p output, when signal isn´t limited.

Thanks for the answer.

Regards,

Vojta

0 Sam(MPAA) Zhang over 3 years ago in reply to Vojtech Kana

TI__Mastermind 19080 points

Hi Vojta,

You may measure the PVDD waveform at the same time. Or simply measure the PVDD voltage on the decoupling caps. I'm suspecting there may be a voltage drop along the cable.

Regards,

Sam

0 Robert Clifton56 over 3 years ago in reply to Sam(MPAA) Zhang

TI__Mastermind 20750 points

Hi Vojta,

Adding to Sam's comment, since this device has a heatsink, if you can't access the PVDD decoupling capacitors safely, try checking the closest onboard PVDD test points. It won't show the full voltage drop to the device but it will indicate if there is any voltage dropping.

Best Regards,

Robert Clifton

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TAS5634: clipping