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TPA3116D2: TPA3116 bootstrap snubbers in PBTL mode

Salwa Feb
Prodigy 40 points
Part Number: TPA3116D2

Tool/software:

Hi TI experts,

I'm currently developing board using TPA3116 chip in PBTL mode. I would like to know how to implement the bootstrap snubbers on this configuration.  On the EVM schematic I saw that in PBTL mode the output P & N are tied together, so can I use just 1 snubber on each channel (one for OUT+ and one for OUT-). If this is possible, then what's the recommended value? Should I keep 330pF & 10R, or should I use the parallel value from both bootstrap snubbers? 680pF & 5R1 perhaps? 

Regards,

Salwa

  • +1
    TI__Genius 10305 points

    Hey Salwa, 

    It seems you are implementing pre-filter snubbers in PBTL mode. After tying the outputs together, one snubber per channel is recommended in this mode. It is also suggested the snubbers are as close as possible to the output terminals of TPA3116D2 on a layout.

    330pF and 10R are acceptable values, no need to implement parallel configuration values here. 

    Regards,
    Ore. 

  • 0 in reply to Ore Ogundana
    Prodigy 40 points

    Hi Ore,

    Thanks for the feedback, it really clears things up. Another question regarding the positioning of these PRE-filter snubbers.. On the EVM for the TPA3116, TPA3118 & TPA3128, these PRE-filter snubbers is located before the inductors and very close to the bootstrap capacitors.. The one close to output terminal are POST-filter snubbers, are you referring to the POST-filter snubbers?

    Regards,
    Salwa

  • +1 in reply to Salwa Feb
    TI__Genius 10305 points

    Hey Salwa, 

    I am not referring to post-filter snubbers in this thread. I am referring to pre-filter snubbers presented in the schematic above. 

    All new EVMs you've mentioned have pre-filter snubbers that follow the one snubber per output channel recommendation. These same schematics also have post-filter snubbers.  

    Regards,

    Ore. 

  • 0 in reply to Ore Ogundana
    Prodigy 40 points

    Thanks for the confirmation Ore, I will move the pre filter close to the inductor / output side. 

    Regards,
    Salwa

  • 0 in reply to Salwa Feb
    TI__Genius 10305 points

    Okay Salwa, 

    Closing this thread now. 

    Regards,

    Ore.