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TPA3255EVM: Audio forum

Mehdi
Prodigy 160 points
Part Number: TPA3255EVM
Other Parts Discussed in Thread: TPA3255

Hello,

I am testing TI evaluation module and I appreciate if you answer my following questions: 

1- For BTL, with differential inputs, the jumper state is actually confusing considering the user guide, quick user guide and the comments in the TI support forums. 

I am using XLR connector to connect AP to the input. What should be the state of jumper J21?

I actually tried with and without J21 and got the same results. Is that correct?

2- I tested BTL configuration, 4ohm loads, 1kHz input signal and at Vin=2.3Vrms, 430W output power (215W per channel) started to see clipping and the indicator LED was turned on at this point. Is it supposed to be like this? How can I increase the power without clipping? For 8ohm load the clipping started at about 200W output power (100W per channel).

3- Can we change the voltage gain of the TPA3255?

 

 

  • 0
    TI__Mastermind 19080 points

    Hi,

    1. J21 is used to control the C_start capacitance. The SE or BTL is referring to the output configuration, not the input. If you are using BTL connection, then you can put J21 OUT. A large C_start capacitance is only necessary for SE configuration to avoid pop-click noise.

    2. You may use an oscilloscope to probe the output(after LC filter) to see if there is any clipping, if not, it may be an over temperature warning.

    3. No, the gain is fixed.

    Regards,

    Sam

  • 0 in reply to Sam(MPAA) Zhang
    Prodigy 160 points

    Hello Sam,

    Thank you very much for your prompt reply.

    According to TPA3255, the maximum analog input voltage swing, peak - peak is 7V (i.e. 2.5Vrms).

    Does this mean that to achieve more than 200W per channel in BTL Configuration, 4ohm load (Fig. 5 in the datasheet) that the input analog voltage should be higher than 2.5V, for sure it starts clipping?

    Best,

  • 0 in reply to Mehdi
    TI__Mastermind 19080 points

    Hi,

    Yes, your understanding is correct. For 4R load, the output power capability is ~260W@1%THD+N, and 315W@10%THD+N.

    Thanks!

    Regards,

    Sam