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TPA6304-Q1: Clip detection is occurring unintentionally

Jayenthiran Rajendran
Prodigy 40 points
Part Number: TPA6304-Q1

Tool/software:

Hi Team, 

We are at present using TPA6304QDDVRQ1 in our design .

Our Question : The Input Signal for the Audio Amplifier has no reduction in clip but the Audio amplifier Output has a clip reduction ( Attached Waveform for the same).

as well the CLIP DET signal is trigged during this event. 

Why the Audio Amplifier is Clipping the Input signal.

Regards

JayYellow → Tuner Output Pink → Amp Output

  • 0
    TI__Mastermind 45085 points

    Hi Jay,

    The audio amplifier has gain and you are providing a large input signal that voltage clips the amplifier.  From your oscilloscope screenshot, I can see that your power supply (PVDD) voltage is approximately 14Vdc and the gain is set to 28dB.  

    You have two ways to keep this from happening:

    1. Reduce in the output level from your tuner module.
    2. Reduce the gain in the amplifier in register 0x03.

    Regards,
    Gregg Scott

  • 0 in reply to Gregg Scott
    Prodigy 40 points

    Hi Gregg Scott, 

    We have a different observation for this test case now. 

    Let me explain. 

    after setting up the hardware DSP and Audio Amplifier with Audio analyzer when we measure the power with 4 Ohm load and max Volume  . the Output Power of amplifier with sec ( 2 to 3 Sec) drops from 20W to 9W . 

    Note : We are using a Heatsink for the IC and the board has a FAN to reduce heat generated. 

    When we measured the Temperature of the IC ( Thermocouple was place in close contact to the IC) , it had measured a value of 45C , so we assume no Thermal foldback has not happened 

    As well the THD is also measured at highest volume is 7% and in IC THD is set to 10%. 


    So what is the reason for drop in Output power of Amplifier.

  • 0 in reply to Jayenthiran Rajendran
    TI__Mastermind 45085 points

    Jay,

    Make sure your power supply is not going into current limit and voltage foldback. 

    To make sure it is not thermal gain foldback, it can be disabled in register 0x33, bit 5.

    Regards,
    Gregg Scott

  • +1 in reply to Gregg Scott
    Prodigy 40 points

    Hi Gregg Scott,

    Power Supply Current limit is 20A and actual current consumption of IVI is close to 8A. and Voltage is set to 14.4V with sense (4W).

    Thermal foldback register is disabled (0x33).

    any other trigger points for reduction in Output power , request you to populate the same.

    Regards

    Jay

  • 0 in reply to Jayenthiran Rajendran
    TI__Mastermind 49800 points

    Hi Jay

    Jayenthiran Rajendran said:
    So what is the reason for drop in Output power of Amplifier.

    There should be no other reasons except for the TGFB control. The tested temperature, would depending on the position of IC, and your heatsink structure. The most simple way to find out, is to use register disable the function, and check again. Thanks.