TPA3221: output power issue

Darren Yang

Expert 2000 points

Part Number: TPA3221

Hi Sir

could you help check above questons and give some way to solve issue,tks!

when we use 1KHZ signal as input, the output power can reach 85W under the conditions of BTL module, however, if we use 4KHZ or more than 4KHZ signal , the TPA3221

only output 25W, if more than 25W power it will distortion，what's more, we also use AP to test, it is the same issue, LC circuit：L=15uH，C=1uf；we also use L=10uH，it is Same invalid

only when the input signal is 1KHZ, it will normal，the SCH as follow, could you help check it and give the suggestions for this qustions,thanks!

over 5 years ago

0 Sam(MPAA) Zhang over 5 years ago

TI__Mastermind 19080 points

Hi Darren,

The high pass filter formed by R-C on input side has too low cut off frequency. 1/(2*pi*1k*1uF)=0.16kHz. Please just short the R6, R17 and try again.

Thanks!

Regards,

Hao

0 Darren Yang over 5 years ago in reply to Sam(MPAA) Zhang

Expert 2000 points

Hi Zhang

it is not use，More than 25W high frequency distortion，could you help test the EVM about what's the max output power when the input singal is 4KHZ to 16KHZ and provide same data for us,tks!

0 Sam(MPAA) Zhang over 5 years ago in reply to Darren Yang

TI__Mastermind 19080 points

Hi Darren,

I measured the gain response vs. frequency on EVM. The results shows the gain curve is heading down above ~2kHz. That's why your output power is decreasing towards the frequency.

LC filter on EVM is 10uH+1uF, with a cut off frequency of ~50kHz. If you have a 15uH, the gain could decrease more.

You may need to consider add some gain compensation for high frequency component on your DSP.

Thanks!

Regards,

Hao

0 Sam(MPAA) Zhang over 5 years ago in reply to Darren Yang

TI__Mastermind 19080 points

Attached the gain frequency response measurement result for different gain settings.

0 Darren Yang over 5 years ago in reply to Sam(MPAA) Zhang

Expert 2000 points

Hi zhang

I cannot understand your mind，if the gain in the 2KHZ the gain will be decrease, I can increase the input signal will be reach more output power, but now my questions is that if we use the input signal frequency is more than 2khz, it only reach max output power is about 25W, if increase input signal and the output power if more than 25W it will be distortion is very serious

0 Sam(MPAA) Zhang over 5 years ago in reply to Darren Yang

TI__Mastermind 19080 points

Hi Darren,

OK, I got your point. I can get at least 80W@2Ohm with 5kHz input.

Could you provide below information?

1. PVIN? Loading resistance? Gain setting?

2. Please compare the amplitude of the signal(Vp or Vpp) with 1kHz/5kHz input.

3. When there is clipping, could you measure the input waveform and see if there is any clipping on input?

Regards,

Hao

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TPA3221: output power issue