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TLV320AIC3204: Very urgent use problem in TLV320AIC3204

Nico Liao
Prodigy 30 points
Part Number: TLV320AIC3204


Hello！

We use the 3204 chip on the C5517 evaluation board with a project. Please help us solve the following problems.

1. What is the 3204 CM (Figure 1), please briefly introduce it?

2. We used an external microphone as the audio collector and input the analog signal to the IN1_L and IN1_R pins of the 3204. We want to know the correspondence between the acquired analog signals and the digital signals. What is the encoding protocol of the 3204, please attach An example is given.

3.In the last experiment, our signal was from the acquisition interface to the input pins IN1_L and IN1_R of the 3204, and then from the DOUT of the 3204 to the C5517. The C5517 processed the signal and sent it to the DIN of the 3204, and then the HPL of the 3204 to the external device. We measured the output signal to find its positive and negative clipping. We guess the reason for the 3204 input voltage and output voltage limiting. Is the input voltage range of the 3204 chip 0-0.9? Please give a possible reason for this phenomenon. Please see Figure 2.

4. As can be seen from the picture of the previous question, the input signal and the output signal have a large delay, and some of the delay must be caused by 3204. What is the total delay of 3204? Please see Figure 2.

5. When using the C5517 evaluation board the day before yesterday, we connected an active speaker to the signal output connector of the evaluation board, which is connected to the HPL/HPR pin in the 3204. The speaker has a strange sound. After a short while, it is found that the 3204 can't capture the audio signal, and the IN1_L/IN1_R pin has no signal input. But occasionally, the 3204 can receive some signals, but the noise is particularly loud. We suspect that it may be a breakdown. Can you help explain the reason?

6. When using the C5517 evaluation board the day before yesterday, we connected an active speaker to the signal output connector of the evaluation board, which is connected to the HPL/HPR pin in the 3204. The speaker has a strange sound. After a short while, it is found that the 3204 can't capture the audio signal, and the IN1_L/IN1_R pin has no signal input. But occasionally, the 3204 can receive some signals, but only noise. And the 3204 HPL/HPR pin detected a voltage of 3.52V. Can you help explain the reason? Is the 3204 chip broken?

  • 0
    TI__Guru 57800 points

    Hi, 

    Welcome to E2E, thanks for your interest in our devices.

    It seems the images you are referencing were not properly uploaded, can you please try again?. Please refer to my comments below.

    1- CM stands for Common Mode voltage of the device, which is the center voltage for the ADC's AC signal. 

    2- The digital interface of the AIC3204 is PCM, which can be set with different formats, such as I²S, Left Justified. Right Justified or TDM. Please refer to section 2.6 of the AIC3204 Applications Reference Guide  (ARG) for more information. 

    3- Clipping should not occur on the DOUT of the device unless a signal higher than the input full-scale voltage (0.5Vrms) is provided to the ADC. If this is not the case on your system, the clipping on the headphone output may be related to a gain increment on the processor or in the DAC side of the codec. Can you please try using the loopback feature of the codec to directly connect the ADC tot he DAC?. This is done by configuring Page 0: Register 29. The picture was not uploaded properly, can you please send it as well?.

    4- The delay of the ADC and DAC is dependent on the filter used for each. For a typical application, where decimation Filter A (delay= 17/Fs)  and Interpolation filter A (delay= 21/Fs)  are used, the total latency expected would be around 38/Fs, which is about 0.79 ms. Please refer to the ARG for more information on the filter selection.

    5- I am afraid I need more information about this issue to check what could be the root cause. Can you please share a diagram with the connections you are using and amplitude of the signals provided/obtained. Also, please share the CODEC register settings. 

    6- Same as above. The 3.5V detected on the HP output is not expected, you should see only the common mode output voltage (same as ADC CM)

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Nico Liao
    TI__Guru 57800 points

    Nico,

    The output waveform of the Headphone driver of the AIC3204 seems saturated, which can be caused by a high gain setting over the signal path. As you can see, the center of the output sine-wave is around 0.9V, which is the device common mode. 

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    Prodigy 30 points

    Diego Meléndez López,

    hello!

    First of all, thank you for your help!
    After our later experiments, the AIC3204 has a limited amplitude and input voltage and can only recognize his maximum input and output voltage. I don't particularly understand what you mean by "caused by a high gain setting over the signal path". I hope that you can give me a suggestion to solve this phenomenon.
    In addition, I would like to know which TI chip can replace the AIC3204. The chip must have both A/D conversion function and D/A conversion function, and the input and output voltage range can reach at least -3.3V~+3.3V.

  • 0 in reply to Nico Liao
    TI__Guru 57800 points

    Hi, Nico,

    I meant that increasing the gain of the audio signal internally by configuring the volume registers could also cause saturation issues.

    In order to solve this issue, you need to make sure the input signal is within the operation levels of the inputs of the codec, and don't apply a high gain to the recorded signal.

    Unfortunately we don't have an audio codec which is capable of handling +-3.3V range, so you may need to include a signal-conditioning stage before/after the codec to set the proper voltage levels on the codec side while being able to handle the system required levels.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer