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TPA3118D2 Fault problem

James Martinez
Prodigy 40 points
Other Parts Discussed in Thread: TPA3118D2

In an application with the TPA3118D2 ic. I am getting my ICs to go into a fault where they cannot get out. For instance, I can connect my audio inputs and power supply to the IC and it functions great even at very high loads. After a few (10 or less) connects and disconnects the IC goes into fault mode, tries to self clear, but never does. So I get the 1 hz enable disable problem. I  have looked at different threads and disconnected my output capacitors, tired different ones too and measured for shorts to my outputs. Everything came up good. Is the ic dead or can this problem be fixed? I have mute tied to GND. SDZ and Faultz are tired to a 100k pullup. I almost directly copied the typical application circuit from the datasheet.

  • 0
    TI__Guru**** 189401 points

    Hi, James,

    Welcome to e2e, and thanks for your interest in our products!

    The TPA3118D2 has a couple different protection features. These are explained on page 18 of the data sheet in the section titled, "DEVICE PROTECTION SYSTEM"

    It sounds like you are familiar with this, and it sounds like you are tripping the over-circuit protection. Try competely disconnecting everything from the output pins and see if that fixes it. If not, then, it sounds like maybe one of the output pins of your IC is damaged.

    -d2

  • 0 in reply to Don Dapkus
    Prodigy 40 points

    Don,

    I guess it is the one of the output pins. Even with all the components taken off from the outputs I still have the problem.  We replaced the ic and the circuit works fine. I am wondering what is causing the ic to fail. I just connect power and it causes this problem randomly, I've tried this on about 6 pcbs and every one has this problem after some connect and disconnects of the power supply.  My bench supply works fine just not in our application. Do I need a soft start supply?

    James

  • 0 in reply to James Martinez
    Prodigy 40 points

    Alright so I figured out my problem.  I have a single ended signal so I must tie my input ground signal to my power supply ground. There was ground noise so I decided to add a 10ohm resistor tying my input ground and power supply ground together. Since the absolute max voltage is 6V on the inputs, there must be damage to the ic because of the ground being tied with a 10ohm resistor. Either that or,because voltage the input signal drives the internal fets and damages them. If I use a 0hm resistor, I never get the ic to fail. I used this AN below to reduce the ground loop noise significantly with the resistor . But now I have the ic getting damaged and failing. I'll try a smaller resistor in the mean time.

    http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=sloa143&fileType=pdf

  • 0 in reply to James Martinez
    Prodigy 40 points

    I there a guide to this video?

    https://www.youtube.com/watch?v=ISILs3MItFE

    In the comments they talk about " we've developed a circuit implementation to eliminate ground noise" . I was wondering what that circuit looked like and how it would help me with my problem.

    So far I still damage the audio ic with a ground loop break resistor of 10ohms. If I tie the grounds together I get ground loop noise but never damage the ic.

    Any help?