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TPA3255: TPA3255 fault and output to the GND

Jonas Dubey
Prodigy 10 points
Part Number: TPA3255

Tool/software:

Hello,

I'm working on a audio amplifier project and I'm running into a problem,

the fault pin is always low ( active-low) and respond to reset correctly

Low-side off the output stage are ON.

Signals in input seem correct until the TPA3255,

I also checked my supply voltage as well as the internal reference voltage :

PVDD = 24v,

VBG = 1.23v,

AVDD = 7.7v,

DVDD = 3.28v.

I also tried to disconnect the output filters and nothing changed.

my configuration is stereo BTL.

Do anyone have an idea why it's not working ?

Thanks, best regards

.E2116_01c_TPA325x CPNV.PDF

  • 0
    TI__Mastermind 18170 points

    Hi Jonas,

    Can you confirm if the reset works properly? The fault pin is pulled low but by activating the reset it will release the fault pin?  

    Above are some of the faults that can be reported by the active low fault pin. 

    If the fault is cleared after activating the reset, then it could be caused by an overcurrent shutdown or thermal shutdown. 

    Also if you could probe the input/output during this scenario that would be helpful. 

    Regards,

    Sebastian 

  • 0 in reply to Sebastian Muriel
    Prodigy 10 points

    Hi Sebastian,

    I confirm that the reset works but the fault pin returns to zero instantly,

    it's probably not a thermal problem because the chip isn't hot at all,

    I also tried to remove the L1-4 inductances and it didn't change anything,

    Here are the results of my measurements, on the left the input signal INPUT_A and INPUT_B and on the right the output.

    Regards,

    Jonas

  • 0 in reply to Jonas Dubey
    TI__Mastermind 18170 points

    Hey Jonas,

    Is this happening on multiple boards or just one? I wonder if there is a damaged component on your board that could be triggering the fault. 

    Is this scenario on power up? Although there is no power up sequence, we do recommend holding reset low for at least 250ms after PVDD is supplied.

    Is there a load connected? I'm curious what the load impedance is and if this happens with no load connected. 

    Also can you check the voltage on the CLIP_OTW and the AVDD pin? 

    Regards,
    Sebastian