TPA3255: TPA3255: Same issue: Premature Clipping and limited output power

Martin Rockwell

Part Number: TPA3255

I'm having the same issue as in the thread and I do know how to measure it.

"TPA3255: Premature Clipping and limited output power"

I have a 48V 1000W power supply. Both my board and the TPA3255EVM eval module are behaving the same way. I am using PBTL mode with a 2 ohm resistive load. The signal is clipping (and the clip warning coming on) about 36Vpk that is 72 Vpk-pk. This is about 325W, not the 575W or so max power I should get from the 48V supply. Po=Vp^2/2*RL or Vpk-pk^2/8*RL.

So what am I doing wrong?

thx,

Martin

over 2 years ago

0 Shadow He over 2 years ago

TI__Mastermind 40410 points

Hi Martin

Sounds it shouldn't clipped at 36Vpk output. Can you use differential voltage probe to test the input signal and also the output voltage at the same time? Capture the waveform and check what is their peak value.

0 Martin Rockwell over 2 years ago in reply to Shadow He

Prodigy 30 points

I'm out of town for a few days. I'll post the screen shot early next week.

0 Martin Rockwell over 2 years ago in reply to Martin Rockwell

Prodigy 30 points

It was a problem with where I set my limiter. Seems to be working to spec now though I'm disappointed with the 20 Hz performance but that seems to be in line with the data sheet. Even with 9000 uF of bulk power supply capacitance it can't hold up full power at 20 Hz.

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TPA3255: TPA3255: Same issue: Premature Clipping and limited output power

"TPA3255: Premature Clipping and limited output power"