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DRV8718S-Q1EVM: Central workaround for Vcp limitation to < 10V?

Lars Rinze
Prodigy 20 points
Part Number: DRV8718S-Q1EVM

Hello,

I would like to drive Nexperia BUK9Kxxx MOSFETs with the DRV8718S.
These MOSFETs are specified to maximum (normal operation) gate source voltage of +/-10V.
DRV8718S's max. charge pump regulator voltage is specified to 11V (both modes, with respect to PVDD); the maxium gate source high level voltage is specified to be equal to the charge pump voltage (==> Vgs_max = 11V on worst case).

Is the any work-around to limit centrally the charge pump voltage to <= 10V? (I would like to safe a 9.1V zener diode across gate and source). 

  • 0
    TI__Guru 55605 points

    Lars,

    Unfortunately, the driver is specified for standard level FETs which are very common in the market.  Is it possible for you to choose a standard level FET?

    Regards,

    Ryan

  • 0 in reply to Ryan Kehr
    Prodigy 20 points

    Thanks for your answer.
    The SPI versions provide the possibility to change (by SPI CP_MODE) between tripler and doubler mode.
    According the datasheet there is a charge pump voltage regulator (not only just the charge pump). 
    It seems to be a quite simple regulator, one for both CP modes.

    Just an idea (for future TI products): If you provide a selection of doubler or tripler mode operation, you should also change the regulation set-points (and i.e. its max. values) between the two modes.

    Another question: I am missing a small bliock-diagrom of the charge-pump. Where is the charge pum sourced from? DVDD or (PVDD + linear voltage regulator)? [As you change at higher PVDD (-> Vcp_so) from tripler to doubler to save power loss, I suppose the CP supply source is PVD+LVR).

  • 0 in reply to Lars Rinze
    TI__Guru 55605 points

    Lars,

    Unfortunately, I don't have a small block diagram to share, but charge pump is sourced from PVDD.  

    I agree, we should consider standard level FET operation with a limitation on max. voltage.  

    Regards,

    Ryan