TPA3130D2: TPA3130D2: Abnormal waveform output without input signal

kaipeng chu

Part Number: TPA3130D2

Hi Sir,

To measure the TPA3130 output for mono woofer application, it is found that the speaker output have an audio 117KHz output without input signal.

when playing 200Hz sound, 117KHz will also be loaded on it

The attachment is the circuit and measurement waveform of MACAN TPA3130.

The power source of AMP is from adapter 20V.

Please help confirm whether there is any circuit need to adjust.

Ken

TPA3130_SCH.pdf

over 3 years ago

0 Xiaolin Qin over 3 years ago

TI__Expert 6295 points

hello Kaipeng,

did you check when you play with 1K signal, how about output after LC filter? according to your schematic configuration, output freq is expected ~400kHZ.

regards

Linda

0 Yanming Gong over 3 years ago

TI__Mastermind 19010 points

Hi Kaipeng,

I think the Master/Slave mode is wrong. Please refer Table 1 in datasheet to configure master mode.

Regards,

Derek

0 kaipeng chu over 3 years ago in reply to Yanming Gong

Prodigy 250 points

Hi Derek,

After changed

1.R1711(R1) to 5.6H ohm and R1710(R2) to un-mount,

2.SYNC PD 100K ohm.

the speaker output also have an audio ~400KHz / 400mV output without input signal.

When playing 200Hz sound, 400KHz also be loaded on it, please see the attached file.

Regards,

Ken

0 kaipeng chu over 3 years ago in reply to Xiaolin Qin

Prodigy 250 points

Hi Linda,

After changed

1.R1711(R1) to 5.6H ohm and R1710(R2) to un-mount,

2.SYNC PD 100K ohm.

the speaker output also have an audio ~400KHz / 400mV output without input signal.

The TPA3130D2 is for Woofer application, the range of working frequency is 20~300Hz.

When playing 200Hz sound, the output after LC filter is 200Hz waveform and 400KHz will also be loaded on.

We will also measure on our AP later. Does the 400K Hz signal affect woofer's sound quality or THD?

Ken

0 Yanming Gong over 3 years ago in reply to kaipeng chu

TI__Mastermind 19010 points

Hi Ken,

400KHz Fsw frequency noise does not affect audio performance(20Hz-20KHz). When you test using AP instrument, you should select AES-17 filter to filter the noise.The datasheet typical data in 6.7 Part is captured on 400KHz Fsw.

Regards,

Derek

0 kaipeng chu over 3 years ago in reply to Yanming Gong

Prodigy 250 points

Hi Derek,

The THD value on 5W speaker at 20V power is higher than the datasheet value, does the TPA3130 need to be divided into analog audio GND? How to divided?

B.R.

Ken

0 Yanming Gong over 3 years ago in reply to kaipeng chu

TI__Mastermind 19010 points

Hi Ken,

It does not need divide audio input to test THD.

Did you select AES-17 filter on AP instrument? and did you check a-weighting noise value?

If a-weighting noise can be correlated to datasheet(Table 6.6, 65uV @20dB), it shows the setup is no problem.

Regards,

Derek

0 kaipeng chu over 3 years ago in reply to kaipeng chu

Prodigy 250 points

Hi Derek,
attached the electrical output signal THD measurement.

B.R.

Ken20200916 TPA3130 electrical output signal THD measurement.pptx

0 Yanming Gong over 3 years ago in reply to kaipeng chu

TI__Mastermind 19010 points

Hi Ken,

The green plot is output voltage, right?

If so, it is been filtered by 300Hz filter, so after 300Hz THD increase. It makes sense.

Regards,

Derek

0 kaipeng chu over 3 years ago in reply to Yanming Gong

Prodigy 250 points

Hi Derek,

Yes, green plot is output voltage and blue plot is output THD.

Add THD table from TPA3130 datasheet into the electrical output signal THD file.

Test Condition : BD Mode/ Gain :20dB/ 4 Ohm@5W speaker/ PVCC 20V

For woofer application, there is a 300Hz filter.

The THD increase between 100Hz~300Hz, Is this the correct value?

B.R.

Ken

0 Yanming Gong over 3 years ago in reply to kaipeng chu

TI__Mastermind 19010 points

Hi Ken,

I think it is caused by output inductor.

You can change other inductor and check again.

Regards,

Derek

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TPA3130D2: TPA3130D2: Abnormal waveform output without input signal