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TAS5760M Digital Clipper

Sadanori Kato
Guru 36540 points
Other Parts Discussed in Thread: TAS5760M, TAS5731M

Hi,

We would like to know the data format and the response speed of the digital clipper.
Is the register of DigClipLev[19:0] fixed-point or floating point?
Could you please tell us data format(e.g. 20bit x.xx number format) and the adjustment data range(xx dBFS to xx dBFS) in detail?
Since there is described "22 Bit Audio Sample in Data Path" on page 32 of data sheet, is the real bit length 22 bits that is treated by the internal BCK?
In addition, can we set the response speed(attack and decay)?
If we can not set it, could you please tell us these values?

Best Regards,
Kato

  • 0
    TI__Guru**** 189401 points

    Hi, Kato-san,

    We will look into this for you.

    -d2

  • 0 in reply to Don Dapkus
    Guru 36540 points

    Hi Don-san,

    Thank you for your reply quickly.
    We are looking forward to your reply for this issue.

    Best Regards,
    Kato

  • 0
    TI__Mastermind 34775 points

    Kato-san,

    The digital clipper in TAS5760M should not be confused with the DRC/AGL of devices like TAS5731M. It is used to set a limit on the max digital value that can be sent to the amplifier. It's more for speaker protection, especially in cases where PVDD is large (e.g. 24V), speaker impedance is small (e.g. 4-ohms) and max output power is low (e.g. 10W). In this case where the PVDD can't be lower to limit the max voltage sent to speaker, the digital clipper can be used to limit the max voltage the sent to the speaker and even add some distortion for loudness effect.

    The 20bit fixed point value for the digital clipper uses 3 registers: 0x01, 0x10 and 0x11. The digital clipper is used in cases where the input signal is much smaller than the possible full-scale value, hence 22 bits is more than suffiecient to sample the input signal.

    Since the output depends on the system digital and analog gains, the best approach is setup the system in it's max operating condition (e.g. 10W) then tune the digital clip level.  For a 24bit word length the range is ~ -6dBFs to -120dBFs.  

  • 0 in reply to Damian Lewis
    Guru 36540 points

    Hi Damian-san,

    Thank you for your explanation.
    However, we could not understand "22 Bit Audio Sample in Data Path".
    So, could you please send us application note or technical documentation of "Digital Clipper"?
    In addition, there is described the calculating formula of Pout on page 36 of data sheet.
    Is the calculating formula correct?

    Best Regards,
    Kato