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TLV320DAC3100: cannot drive 8ohm speaker

yf liao
Expert 1080 points
Part Number: TLV320DAC3100

Hi, we met a problem that TLV320DAC3100 cannot drive a 8ohm speaker. SW investigation shows there is overcurrent event occurred. There are two 100nF capacitor pararlled on SPKOUT+ and SPKOUT-. This issue didn't show on our LP1 board, but it shows on recent LP2 board. The difference between the two boards are on LP2 the SPK+ SPK- trace is widen from 4mil to 15mil, and the filter capacitor keeps 100nF but package is changed from 0603 to 0402. 

The voltage on SPK+ and SPK- output on LP1 is captured as this:

On LP2 board, the output waveform is as below, the SPK+ and SPK- keeps high for a long time(around 160us) then turns off, after that there is no more output:

Please advise what is the over current threshold of the driver, and what possible reason cause the issue?

  • 0
    TI__Guru* 84915 points

    Hi, yf,

    Could you provide your circuit schematic and your registers configuration before and after the overcurrent protection appears, please?

    Thank you

    Best regards,

    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    Expert 1080 points

    hi, attached register dump on LP1 and LP2 board, and schematic.

    8875.Audio_LP1_Register.txt 
    No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 00 00 01 66 03 91 08 07 80 00 00 88 82 00 80 80    ..?f?????..??.??
10: 08 00 88 82 80 80 04 00 00 00 01 4c 00 04 88 00    ?.?????...?L.??.
20: 00 00 00 00 80 98 10 a0 80 00 00 00 00 00 00 00    ....?????.......
30: 00 00 00 02 32 12 03 02 02 11 10 00 01 04 00 b0    ...?2??????.??.?
40: 00 30 30 00 6f 38 00 00 00 00 00 ee 10 d8 7e e3    .00.o8.....???~?
50: 00 00 80 00 00 00 00 00 7f 00 00 00 00 00 00 00    ..?.....?.......
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ?...............
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04    ...............?
20: 86 3e 00 40 7f 7f 80 7f 02 02 1d 00 20 86 00 80    ?>.@???????. ?.?
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 03 00 00 00 00 00 20 00 00 40 00 00 00 01 0f 40    ?..... ..@...??@
10: 81 81 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ??..............
20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 04 00 01 17 01 17 7d d3 7f ff 00 00 00 00 7f ff    ?.????}??.....?.
10: 00 00 00 00 00 00 00 00 7f ff 00 00 00 00 00 00    ........?.......
20: 00 00 7f ff 00 00 00 00 00 00 00 00 7f ff 00 00    ..?.........?...
30: 00 00 00 00 00 00 7f ff 00 00 00 00 00 00 00 00    ......?.........
40: 00 00 00 00 00 00 00 00 7f ff 00 00 00 00 7f ff    ........?.....?.
50: 00 00 00 00 00 00 00 00 7f ff 00 00 00 00 00 00    ........?.......
60: 00 00 7f ff 00 00 00 00 00 00 00 00 7f ff 00 00    ..?.........?...
70: 00 00 00 00 00 00 7f ff 00 00 00 00 00 00 00 00    ......?.........
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

    5415.Audio_LP2_Register.txt 
    root@am335x-evm:~# i2cdump -f -y 0 0x18
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 00 00 01 66 03 91 08 07 80 00 00 88 82 00 80 80    ..?f?????..??.??
10: 08 00 88 82 80 80 04 00 00 00 01 4c 00 04 88 00    ?.?????...?L.??.
20: 00 00 00 00 80 88 10 a0 80 00 00 00 80 00 00 00    ....?????...?...
30: 00 00 00 02 32 12 02 02 02 11 10 00 01 04 00 b0    ...?2??????.??.?
40: 00 30 30 00 6f 38 00 00 00 00 00 ee 10 d8 7e e3    .00.o8.....???~?
50: 00 00 80 00 00 00 00 00 7f 00 00 00 00 00 00 00    ..?.....?.......
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................


     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ?...............
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04    ...............?
20: 06 3e 00 40 7f 7f 80 7f 02 02 1c 00 20 86 00 80    ?>.@???????. ?.?
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 03 00 00 00 00 00 20 00 00 40 00 00 00 01 0f 40    ?..... ..@...??@
10: 81 81 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ??..............
20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 04 00 01 17 01 17 7d d3 7f ff 00 00 00 00 7f ff    ?.????}??.....?.
10: 00 00 00 00 00 00 00 00 7f ff 00 00 00 00 00 00    ........?.......
20: 00 00 7f ff 00 00 00 00 00 00 00 00 7f ff 00 00    ..?.........?...
30: 00 00 00 00 00 00 7f ff 00 00 00 00 00 00 00 00    ......?.........
40: 00 00 00 00 00 00 00 00 7f ff 00 00 00 00 7f ff    ........?.....?.
50: 00 00 00 00 00 00 00 00 7f ff 00 00 00 00 00 00    ........?.......
60: 00 00 7f ff 00 00 00 00 00 00 00 00 7f ff 00 00    ..?.........?...
70: 00 00 00 00 00 00 7f ff 00 00 00 00 00 00 00 00    ......?.........
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

    7416.schematic.docx

  • 0 in reply to yf liao
    TI__Guru* 84915 points

    Hi, yf,

    Do you get the same results if you remove the 100nF capacitors C265 and C266?

    Could you also try removing the diodes CR34 and CR35?

    The idea is leave the output lines without additional components in order to determine if the root cause is related to the PCB traces or not.

    Please let me know how it results.

    Thank you. Have a good day.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    Expert 1080 points

    We have changed 100nF capactior to 470pF on LP2 board, the speaker can work. Another experiment is keep 100nF but add a segment of flywire into the trace before connect to the speaker, it also works. It looks like the wider trace contribute to the failure. However we want to further understand the root cause, please advise:

    1. How does the TLV320DAC3100 detect the overcurrent? What's the threshold in terms of over-current value and the detection duration?

    2. Why a slight change in trace width lead to different situation, is it because 2*100nF already make the impedance of the loading very low so any factor that can make the impedance below 8ohm trigger the overcurrent? If so, we still want to know the answer of question #1, where is the TLV320DAC3100 limit, so that we need to keep above with, seems there is no mention in the datasheet.

  • 0 in reply to yf liao
    TI__Guru* 84915 points

    Hi, yf,

    There are no much details about the short-circuit protection in the TLV320DAC3100. Short-circuit protection on Class-D output triggers when SPKVDD supply goes over ~500mA. This is just an estimation obtained from a bench test. However the protection on Class-D is mainly purposed as Short-Circuit protection.

    Best regards,
    Luis Fernando Rodríguez S.