TPA3255: Speaker-current feedback with PBTL mode

TotoWood

Part Number: TPA3255

Welcome,

I want to use Speaker-current-feedback [partially simple motional-feedback] for the TPA3255 amplifier with PBTL mode.
One way speaker impedance of 4 ohms, resonance impedance peak corrected, relatively linear.

How do I do it?

Thank you responce.

over 7 years ago

0 TotoWood over 7 years ago

Prodigy 140 points

Just Analog way, no nonlinear DSP control.

Rsunt = 0.15 ohm

0 Justin Bohr over 7 years ago in reply to TotoWood

TI__Mastermind 27990 points

Hi TotoWood,

I would recommend taking a look at this Post Filter Feedback app note. It explains how we have implemented a feedback loop from the output of the LC filter to the input of the TPA3255. It can be found in the technical documents tab of the TPA3255 product page.

Justin

0 TotoWood over 7 years ago in reply to Justin Bohr

Prodigy 140 points

Dear Justin,

Thank you for your answer. I read before.
But: I want to use Speaker feedback [partially simple motional! feedback]

Current Sense Amplifier, etc...

0 Justin Bohr over 7 years ago in reply to TotoWood

TI__Mastermind 27990 points

Hi TotoWood,

We do not have any reference designs that implement a current sense circuit in an analog way. It sounds like you have an idea on the components needed, a sense resistor and current sense amplifier. The difficult part will be transforming that current sense feedback into the right feedback voltage for the input. We do not have a solution for this. You may try taking a look at current sense amplifier solutions from the OP Amp team and start from there.

Justin

0 TotoWood over 7 years ago in reply to Justin Bohr

Prodigy 140 points

" The difficult part will be transforming that current sense feedback into the right feedback voltage for the input. "

Yes, difficult but it's worth. Real motional feedback is optical [displacement sensing], but this is not bad for woofer.
If you have any new ideas, please share it with me. Nonlinear controlled DSP feedback is not good.

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TPA3255: Speaker-current feedback with PBTL mode