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TAS5715EVM GDE UI processing blocks issue

Sean Bigley
Genius 17175 points
Other Parts Discussed in Thread: TAS5715, TAS5751M, TAS5727, TAS5731M, TAS5733L

Team,

I'm working with a customer who is evaluating our TAS5715 using the EVM. They are having issues manipulating the processing blocks in the UI, details below:

Setup-

  • TI GDE running on Win7 Pro platform
  • Have ran I2C memory tool as described in section 3 of SLOU304
  • With target menu item selected, "Connect" yields the following in the output window
    • Target connected
    • Setting EVM state... Done
  • After UI active, EVM configured for analog inputs via RCA inputs

After configuration, no sound is produced, but when un-mute is selectetd on the master volume control on the GDE, the unit produces sound. However, any attempt to manipulate any of the processing block is unsuccessful.

Comments from the customer below:

  1. trying to run the master gain up generates very high levels about 20% of the way up from the bottom, and then it shuts down. Pushing the fader up further it starts producing sound again until it's about 70% of the way up, gets to a very high level, and shut down again.

  2. There are two controls immediately prior to the master volume labeled Ch1Vol1 and Ch1Vol2. It's not clear what purpose they serve, but making even tiny changes to these value results in a dramatic increase in output level, which can only be resolved by muting and unmuting the master volume control. The values seem to be any signed float value, but it does not seem to have any major effect, other than what I observed above.

  3. I have configured the system to use only one path through the initial Biquads, and am not using any of the crossover facilities. When I click on the first (input) biquad, I set it as a variable-Q high-pass with Fc=180Hz and Q=2.0, then click the apply control. I can see the response I am looking for being drawn, but it has no apparent effect on the response of the system, I have gone so fa as to set the Fc=8000Hz, which should have a dramatic audible effect, but applying the filter seems to have no effect audibly

  4. Similarly, trying any of the other biquads does not seem to have an audible effect

Any comments on the above observations would be appreciated.

-Sean

  • 0
    TI__Guru 57800 points

    Hi, Sean,

    I would like to mention that TAS5715 is quite old and the GUI is certainly not the best. We have newer amplifiers which performance, reduced BOM, easier end-system integration (PPC3 compatible) and collateral information makes them a better option for new designs. Perhaps the TAS5751M could be a good choice.

    About your question, I will try the steps you mention with the EVM and get back to you probably by tomorrow. 

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    TI__Genius 17175 points
    Diego,

    Thanks for the info. I'll definitely pass this information along, and appreciate any help you can give on the above as well.

    BR,
    Sean
  • 0 in reply to Sean Bigley
    TI__Guru 57800 points

    Hi, Sean,

    I performed some tests in the EVM. I have no issues with the TAS5715 GUI, but after opening the GUI I noticed that the default process flow on the GUI is the  TAS2727. After connecting the TAS5715 with the TAS5727 GUI, I was able to replicate your customer issue:

    • The volume uncontrolled changes are related to the volume register size, being 2 bytes for the TAS5727 and 1 byte for TAS5715. 
    • It seems that your customer was using the first biquad of the TAS5727GUI, it is controlled via register 0x27. In the TAS5715, Register 0x27 is reserved, so there is no change applied to the amplifier.

    The process flow specific for the TAS5715 can be selected in Devices > TAS57xx > TAS5715:

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    TI__Genius 17175 points

    Diego,

    I'm looking for a class-D amp to suggest for these specs. Can you help me figure out if my recommendation will be acceptable, and if not, can you suggest a better device? Specs below:

    • At least two configurable biquad or similar 2nd-order filter functions, one configurable as a 2nd-order under-damped (Q=2) high-pass in the region of 100-250 Hz, the second as a 2nd order over-damped (Q=0.4-0.6) low pass in the region of 15 kHz.
    • Frequency-dependent limiting to act as protection against over-driving the loudspeaker driver. At lower frequencies (< ~600Hz), it should provide a 1/f^2 profile to guard against mechanical limits, above that the ultimate limit would be determined by the thermal properties of the driver and thus would generally have a frequency-independent function.
    • Input will be I2S, most likely a 48 kHz sample rate.

    • Practical maximum power the loudspeaker driver can handle is about 10 watts continuous: more than that could only be handled on a very short term basis (less than a few dozen milliseconds) at higher frequencies to prevent thermal overload (which results in permanent damage), and at lower frequencies, needs to be managed by the limiting system to prevent mechanical overload (which results in, initially, audible distortion but, ultimately, permanent damage)

    I was thinking of suggesting either the TAS5751M (as you suggested above), or the TAS5731M. Would one be better than the other for these specs?

  • 0 in reply to Sean Bigley
    TI__Guru 57800 points

    Hi, Sean,

    I think both TAS5751M or TAS5733L could meet the requested specs. The Audio processing of both amplifiers is the same, having up to 10 biquads per channel, as well as a three-band AGL that can be used to limit the output at different frequencies and a full-band AGL that can limit the output power at the desired level. Both amplifiers could handle 10W easily, but as TAS5751M is designed to handle larger power levels, probably TAS5733L could be a better choice. 

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer