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DRV8301 3 phase pre driver with Integrated Buck Regulator

SUnderwood1
Prodigy 40 points
Other Parts Discussed in Thread: DRV8301, TPS54160

The DVR8301 has a integrated buck regulator  but there is no design information in the data sheet for a switcher of this type.  There needs to be  equations/ graphs for selecting the timing frequency resistor, input/ output caps, Inductor ,  etc  as would be found on a dedicated switcher data sheet.  It appears to be the same type as a TPS54160 family.    What document is to be used to design the regulator component selection on the  DRV8301 ?   I dont want to use the parts and components that are described in the schematic  in the EVAL kit  for the DRV8301.  Thanks

  • 0
    TI__Guru 55615 points

    Please use the TPS54160 document as a reference.  It is exactly what you need for the DRV8301.

     

  • 0 in reply to Ryan Kehr
    Prodigy 40 points

    Ok Great.

     The DRV8301 data sheet block diagram indicates the buck regulator power input (PVDD2) is completely independent from the motor driver power in (PVDD1). So I can run the buck regulator on PVDD2  with the rest of the driver unpowered (PVDD1) ?   correct?     Is there any issue if the buck regulator is somehow shut off but the  PVDD1 driver power is still on?  

    Is there a way to estimate/calculate the expected temperature rise in the 8301 package just from the buck power supply component alone? (assuming I know the Vout load)

    Thanks

  • 0 in reply to SUnderwood1
    TI__Guru 55615 points

    The PVDD1 and PVDD2 terminals are NOT connected in anyway.  It is OK to operate them completely independant of each other.

    To calculate power dissipation, I recommeded looking at page 39 in the document below.  This datasheet models the buck inside the DRV8301 and can be used to calculate expected temp rise.

    http://www.ti.com/lit/ds/symlink/tps54160.pdf

     

  • 0 in reply to Ryan Kehr
    Prodigy 40 points

    The DRV8301 has a large heatsink area on the package . So my question is how is the Pd calculation from the TPS54160 MSOP10 going to translate to the 56 HTSSOP heat rise?  How is the TPS54160 die situated/ related to the DRV8301 heatsink ?  Conversely, how much heat from the DRV8301 will flow into the TPS54160 area?  are they thermally isolated?

    Thanks

  • 0 in reply to SUnderwood1
    Prodigy 40 points

    On the DRV8301, if I force the  EN_GATE  from high to low to shut down the outputs,  does that mean the  DRV8301 gate drives (GH_X & GL_X)  are immediately driven low by the DRV8301 to force 'off' the external FETS ?  or are DRV8301 output drives to the gates just put in a high impedance state (regardless of the present drive state)?  

    Basically I want to force all the external FETS off immediately, independent of the PWM uP commutation commands.  Is the EN_GATE pin the place to do that?   

  • 0 in reply to SUnderwood1
    TI__Guru 55615 points

    EN_GATE is the pin you want.  It forces the outputs LOW, so the external FETs will go to a HIZ state. 

    Sorry, this should be more clear in the datasheet.  It can be used asynchronously to PWM commands from the MCU.