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TAS2559: Could you check PPC3 setting file?

Downey Kim
Expert 2675 points
Part Number: TAS2559

Hi TI team,

My customer designed TAS2559. 

There are some problems. 

1. The output is saturated at 1.3W. they want a 3.5W @THD 1% spec.

2. The output of 1khz is 12db lower than other frequency bands.

3. The same phenomenon occurs when the same PPC3 setting is applied to the EVM.

Attached the ppc3 setting value. please check it.

sp_191104.zip

If you have a reference PPC3 setting file to apply to EVM, please provide it.

Thanks,

Downey Kim.

  • 0
    TI__Guru* 95085 points

    Hi Downey,

    I'll take a look at the configuration. A couple questions/comments:

    • What speaker are you using?
    • For output power vs THD measurements, you should use ROM mode, not tuning mode. Are you using ROM mode?

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

  • 0 in reply to Ivan Salazar
    Expert 2675 points

    Hi Ivan,

    • What speaker are you using?

    They were measured with an AP equipment. Measured with no load, 4ohm, 8ohm load, but no output over 1.3W.

    • For output power vs THD measurements, you should use ROM mode, not tuning mode. Are you using ROM mode?

    Yes, Using Rommode1.

    Thank you.

    Downey Kim.

  • 0 in reply to Downey Kim
    TI__Guru* 95085 points

    Hi Downey,

    If you're not using a load, how would you know the reference for the power measurement? I've tried your ppc3 file on my setup and I'm able to get output higher than 3W for 8-ohm load.

    Can you share captures of your ppc3, AP and hardware setup for the test?

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

  • 0 in reply to Ivan Salazar
    Expert 2675 points

    Hi Ivan,

    Thanks your check.

    Did you test with TAS2559EVM?

    could you provide your AP setup file? we will measure with TAS2559EVM.

    we will try to measure it with TAS2559EVM with your setup file.

    Thanks.

  • 0 in reply to Downey Kim
    Expert 2675 points

    Hi Ivan,

    I confirmed with TAS2559EVM. The output does not rise more than 1W with the reference PPC3 setting. (4ohm load)

    When playing a sine wave sound source, boost mode is not entered. EVM was tested with a mono hardware setting in the user guide.

    Also, at the customer's ppc3 setting, 2khz 0dB output is twice the 1khz 0dB output. (EVM hardware setting is Mono)

    Please tell me your measurement condition on TAS2559EVM.

    Thanks.

  • 0 in reply to Downey Kim
    Expert 2675 points

    Hi Ivan,

    I'm sorry to push, when can I get the answer?

    Thanks.

    Downey KIM.

  • 0 in reply to Downey Kim
    TI__Guru* 95085 points

    Hi Downey,

    There is nothing special on my AP configuration. I only connect the output of the Class-D to the load and low-pass filter, and then to the analog inputs of the AP.

    Regarding the device configuration:

    • Open PPC3
    • Load your ppc3 file
    • Enter Tuning and Audio Processing panel
    • Go back to main panel
    • Enter Test and Measurement panel and click on ROM Mode 1

    If the output is not going higher than 1W, and 1kHz has different amplitude than 2kHz then the device is most likely operating in the tuning mode.

    Can you read register 0x22 on page 0, book 0? This register will say in which mode the device is operating.

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

  • 0 in reply to Ivan Salazar
    Expert 2675 points

    Hi Ivan,

    Thank you for your advice! 

    When measured in the Test and Measurement panel, 3W or more is output.

    However, when measured on the Tuning and Audio Processing panel, it is less than 1W.

    When testing a customer's product, the same phenomenon as that measured in the Tuning and Audio Processing panel. Please tell me how to improve it.

    **register 0x22 on page 0, book 0 = Smart AMP mode.

    Thanks,

    Downey Kim.

  • 0 in reply to Downey Kim
    TI__Guru* 95085 points

    Hi Downey,

    When you enter Tuning and Audio Processing panel, the device reprogrammed back to Smart Amp mode (it goes out of ROM Mode).

    ROM mode does not feature any of the processing tools, why do you need to go back to the tuning panel?

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

  • 0 in reply to Ivan Salazar
    Expert 2675 points

    Hi Ivan,

    My customer application is AI SPK. The source for TAS2559 is programmed into the TAS2559 by the CPU.

    We test with the set they made. It is not connected to the PPC3 program.

    Please answer the questions below.

    1. Please tell me the difference between Smart AMP mode and Rom mode. Looking at the datasheet, it is understood that it outputs more than 3W even in smart amp mode.

    2. If I change the 0x22 register to 1 or 2(Rom mode1 or mode2), can I output more than 3W even if the set and PPC3 are not connected?

    Thanks,

    Downey Kim.

  • 0 in reply to Downey Kim
    TI__Guru* 95085 points

    Hi Downey,

    Let me make some comments on your questions below:

    1. ROM mode is basically a boosted Class-D amplifier, no signal processing is enabled. Smart Amp mode on the other hand has all the signal processing enabled, like EQ, DRC and speaker protection.
      One important thing is that speaker protection will prevent damages to the speaker. The device protects the speaker from over-excursion of the diaphragm and over-temperature of the voice coil, based on the speaker characterization.
    2. Yes, by setting that register the device will change to ROM Mode, regardless if it's connected to PPC3.

    The speaker protection is used to maximize the audio output while keeping the speaker operating in a safe region both in temperature and excursion. Testing smart amp mode with single tones will limit the output power because a single tone (specially 1kHz for some speaker) can heat considerably the voice coil, thus the speaker protection reduces the output to protect the speaker. You can test smart amp mode using broadband audio content and measuring RMS power at the output.

    However it is most common to test the device in ROM Mode and do it like any other Class-D amplifier.

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