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TPA3255: Running on 13S Battery 54.6V

Stephan Gnos
Prodigy 10 points
Part Number: TPA3255
Other Parts Discussed in Thread: TAS5634

Hi

I want to use TPA3255 amplifier board with 13S battery. With full charge battery will reach to 54.6V. Can you tell me, if that can work. you say 53.5V on 6ohm. i will using 4ohm driver. but TPA3255 also say max V is 69 (or 63V). So therefore i'm wonder if i can use 54.6V battery? the bigger caps on the board i can see are 63V.

Thank you very much

  • 0
    TI__Mastermind 19171 points

    hi, Stephan

    if you use 4ohm as the load, we don't recommend use the pvdd voltage over 53.5v as the datasheet said.

    over 53.5v with 4ohm has risk for no validation for this condition.

    tks

    jesse

  • 0
    Prodigy 30 points

    FYI Stephan,

    Some years ago, I had the very same questions. Therefore I tested by creeping the PVDD higher and higher. The IC begins to get pretty damned hot at these voltages. I never destroyed the IC, but it did not feel comfortable at over 55V. If you look at the digital input version TAS5634 this has a recommended rating considerably higher at 58V, but strangely the absolute max on this IC is only 65V. Whereas the TPA3255 states 53.5V and 69V respectively. Note also the the bridge MOSFETs in both ICs are 80mOhm. Seems to me like they share the same output stage.

    I asked this question to TI some some years ago and the answer was they use a different manufacturing process. Do not exceed the limits..... Well, seems a bit sketchy.

    However, as I said, regardless of where the true upper limit lies, these babies start to get pretty darn hot at high voltages. You must properly heatsink and pulling heat of that TTSOP surface can be a challenge. Also getting closer and closer to the absolute max leaves less room for any potential transient overvoltages on the bus. 

    Having said this, I don't think TI ever convincingly explained to me the clear contradictions between the datasheets of the TPA3255 and the TAS5634. I suppose it's not unlink a old fashioned motor engine. If you want a reliable workhorse stick with a tractor engine; low revving diesel. If you want to win the Brazilian GP, then go for a Turbo charged gas monster at 25K rpm.   But you might not make it to Monaco. 

    Hope my 2 cents is helpful.

    Aidan

  • 0 in reply to Aidan Walton
    TI__Genius 14960 points

    Hello Aidan,

    The TPA3255 and TAS5634 are different designs. We only guarantee proper device functionality in the recommended operating conditions, anything past that has high risk to reliability and device operation. 

    best regards,
    Luis