• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 30 subscribers
  • Views 465 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPA3255EVM: Modifications for 4-channel operation?

matt Hanson
Prodigy 10 points
Part Number: TPA3255EVM

I'm a newbie to electronics, so please go easy on me...


I have been told that this module only works in 4-channel mode, if pins are de-soldered prior to use. (I was given pins J22 and J25, and their corresponding pair on the opposite side of the board)

However, I don't wish to make modifications to this board, and wonder if you can please tell me why I was told to modify it in this way.  If I'm reading the user manual correctly, I can run this without the mod.  But someone who used this board before me, seems thoroughly convinced that this MUST be done.

Thank you.

  • 0
    TI__Mastermind 27990 points

    Hi Matt,

    Section 3.3 of the EVM User's Guide shows what configuration the board needs to be in to operate in SE mode (4 single ended channels). It is required that you remove J22, J23, J24, and J25 to operate in SE mode. This is because in SE mode the speakers will be connected to the amplifier on one end and GND on the other. The amplifier output will operate at an offset of PVDD/2, which if directly connected to the speaker, would cause a DC offset of PVDD/2 damaging the speaker/not producing high quality audio.

    In order to avoid this a DC blocking cap is used on the outputs. However, in BTL more or PBTL mode these Dc blocking caps are not needed. So in order to create an EVM that can handle both scenarios, we added DC blocking caps to the output, but bypassed them with jumpers J22 to J25.

    As a result, in order to operate in SE mode this bypass must be removed so that the speakers are AC coupled and the DC offset of the amp output is blocked.

    Justin