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TPA3245: OCP

Kai Hsiao
Guru 12675 points
Part Number: TPA3245
Other Parts Discussed in Thread: TPA3255

Hi Sir 

Does TI have similar output watt solution with TDA7498E

OCP 11A when Rload=0ohm (0ohm is necessary) 

(TPA3245 is 13.5A when Rload=1ohm) 

  • 0
    TI__Mastermind 27880 points
    Hi Kai,

    Sorry about the delay. Could you explain more about your use case? The TPA32XX family of devices have short protection to protect against a 0R situation.

    Justin
  • 0 in reply to Justin Bohr
    Guru 12675 points

    Hi Justin 

    This is a special application .our end customer use TPA3245 to driver a transformer and the structure like below 

     

    When test with TPA3245 

    1. BTL Mode(INA+INB)

    2. Input Sine wave 1.2Vrms ,the CLIP_OTW LED will indicate and this moment the output voltage is under 10Vrms 

    3. At the same condition ,TDA7498E is workable 

    So I guess TPA3245 is OCP ,do you have any suggestion or others solution can replace TDA7498E?

  • 0 in reply to Kai Hsiao
    TI__Mastermind 27880 points
    Hi Kris,

    What supply voltage are you using with the TPA3245? Are you still using the boot strap caps and output LC filter?

    The TPA3255 would be a drop in replacement that can handle more current, but it will still have the same OCP protection in a 0R situation.

    Justin
  • 0 in reply to Justin Bohr
    Guru 12675 points

    Hi Justin 

    I can check supply voltage again 

    1. you mean boost strap cap need to modify ,do you have any recommend value?

    2. I need to remove LC filter ? is it correct ?

  • 0 in reply to Kai Hsiao
    TI__Mastermind 27880 points
    Hi Kai,

    1. No you do not need to modify boot strap caps.

    2. I belive you should still use LC filter, unless you can guarantee that the inductance on the output pin is at least 5 uH at all output scenarios.

    Are you expecting the amplifier to continue to operate when the load is equal to 0 ohm? Our parts are designed to protect themselves when there is a short (Rload = 0).

    Justin
  • 0 in reply to Justin Bohr
    Guru 12675 points
    HI Justin

    I curious why ST solution could work for system and TI can't work it at the same system structure ,due to ST Ilimit is the same for 11~12A

    TPA3245 EVM fail condition as below
    Input Sine wave 1.2Vrms ,the CLIP_OTW LED will indicate and this moment the output voltage is under 10Vrms

    I will check which ST EVM could be used
  • 0 in reply to Kai Hsiao
    TI__Mastermind 27880 points
    Hi Kai,

    This might have to do with the over current protection choices made for each part. Currently on the TPA3245, there is latching and CB3C over current protection. The latching option will shut down the part immediately if the current limit is reached, while CB3C will let the part continue to operate past the initial output hitting the current limit, but eventually still shut down due to over current.

    For the failing scenario for the EVM, is the TPA3245 shutting down? The CLIP_OTW pin will illuminate before the amplifier starts clipping as it is a pre-clip pin as well as the over temp warning pin. If the pin is toggling that is just from clipping or pre-clipping.

    Justin