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TAS2557: Asking for TAS2557 design qeustions

SHH
Mastermind 32346 points
Part Number: TAS2557


Hi Team,

Would you please help for TAS2557 questions?

1. If the IV sense is not direct from speaker pads. Is there any impact for IV sense ?
2. Could TAS2557 detect two different impedance of speaker by IV sense (7.5ohm and 6ohm) ?

txn.box.com/.../jygv54emw3rmh28tre208gjm7mpg3r4u

BR,

SHH

  • 0
    TI__Guru* 84915 points

    Hi!

    Our team will take a look at these questions and will answer as soon as possible.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0
    TI__Guru** 111705 points

    Hi SHH,

    Let me comment on your questions below:

    1. As mentioned in data sheet section 9.3.9, any resistance or non-linearities after the IV-sense pin connections would not be considered for the internal processing. It would be best to connect IV-sense pins after the output filter (also mentioned in this section).
    2. IV sense works only for one speaker connected, if two speakers are connected in parallel the performance would be compromised.

    Regarding the schematic, it looks good except for the IV-sense connections. Make sure to place the decoupling capacitors for all supplies as close as possible to the device, and use X7R or better at least for VBAT and Boost.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    TI__Mastermind 32346 points

    Hi Ivan,

    Actually, customer provide two different impedance of speaker to end user. They only can use one of speakers for this phone.
     Could TAS2557 detect two different impedance of speaker by IV sense and change the parameter of speaker used by end user?

    BR,

    SHH

  • 0 in reply to SHH
    TI__Guru** 111705 points

    SHH,

    Each speaker should be characterized and tuned for best audio performance.
    The device would be able to detect different impedance for different speakers, but if it is characterized for only one of them then the speaker protection algorithm would only work correctly for the one it was characterized and tuned for.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    TI__Mastermind 32346 points

    Hi Ivan,

    Would you please help for questions?

    1. How customer calibrate impedance at production line ?
    2. How user calibrate impedance if boot up the phone ?

    BR,

    SHH

  • 0 in reply to SHH
    TI__Guru** 111705 points

    SHH,

    Factory test calibration tool can be used and production line.
    The same calibration is used during boot up.

    You can find more details on this tool in this App Note: https://www.ti.com/lit/an/slaa779/slaa779.pdf

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    TI__Mastermind 32346 points

    Hi Ivan,

    So just to confirm, it’s now clear to TI team that we have an existing speaker and we are developing a new one. Each device would only have one speaker. And TAS2557 is able to detect the different impedance and load the corresponding parameters. Correct?

     

    BR,

    SHH

  • 0 in reply to SHH
    TI__Guru** 111705 points

    SHH,

    The device is able to detect the speaker characteristics due to IV-sense. However the parameters are not changed based on this, the speaker protection algorithm is based on the speaker characterization data, if the speaker characteristics are deviated from the  characterization data, the algorithm will try to compensate but the parameters are the same.

    If the speaker is changed, then the characterization data must be changed as well.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators

  • 0 in reply to Ivan Salazar
    TI__Mastermind 32346 points

    Hi Ivan,

    Thanks for reply. Would you please help for the following two questions?

    1. Are there two bin file (tas255x_cal_1.bin and tas255x_cal_2.bin) setting into the TAS255X.?
    2. Could you provide the software including twice calibration ?

    3. if customer changed different TS model speaker, can TAS2557 detect the different speaker and trigger MCU to set different calibration data?

    BR,

    SHH

  • 0 in reply to SHH
    TI__Guru** 111705 points

    SHH,

    This is not supported at this moment. The smartamp can be calibrated only by using one calibration file. FTC tool uses this cal.bin file.
    The device cannot report back a mismatch in speaker IV-sense measurements and characterization data.

    If the speaker changes, then speaker char data must be changed for device calibration.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators