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DRV8302 in application with Vmotor (PVDD1) from fast 0v to 48V.

zbyno brudny
Prodigy 120 points
Other Parts Discussed in Thread: DRV8302, DRV8303, DRV8301

 I would like use a application with forward DC/DC conversion like in DRM078 from freescale ( bldc-Motor has L about 60uH only).

I want to disable the overcurrent-functionality (page 14:ConnectOC_ADJ  pin to DVDD to disable the over-current protection feature.) 

And connect on Pin PVDD1-29 wired-OR of 10V-supply and output of DC/DC-convertor for motor-voltage.

see in 3-Phase BLDC Drive Using Variable DC Link Six-Step Inverter , Designer Reference Manual, DRM078 Rev. 1 05/2006- freescale, page 12:

It is correct? Will it good work?

Zbyno

  • 0
    TI__Guru** 114905 points

    Hi Zybno,

    What you have describe should work with the DRV8302. May I suggest that you also look at the DRV8303 if you do not need the buck.

    Also, please consider looking at the DRV8301EVMs available in the estore for evaluation. This may provide a fast method of checking out the operation and features needed.

  • 0 in reply to Rick Duncan
    Prodigy 120 points

    Thank you Rick,

    It was a surprise for me, that nobody didnt tested this functionality .I see theoreticly a problém when Vmotor voltage  will be less than 10V (start-up of motor, for example 2V), but PVDD1-voltage will be 11V (supplied from wired-OR). What about Vgs-max of  upper FETs in this case?

    I have bought DRV8301-BoostX and I will test my (customer) idea with DRV8301.

    Best regards

    Zbyno

  • 0 in reply to zbyno brudny
    TI__Guru** 114905 points

    Hi Zbyno,

    I did not mean to imply that no one has tested this functionality. I did a quick search and found several questions on the forum regarding low inductance motors.

    In addtion to the motor drivers forum, the c2000 forum also fields many questions about InstaSPIN and low inductance motors.

    One blog was also located that may be of interest:

    http://e2e.ti.com/blogs_/b/motordrivecontrol/archive/2013/11/07/you-will-not-be-able-to-spin-this-motor.aspx

    Our design group has informed me that  PVDD1 and the motor voltage must be the same. As long as PVDD1= VM, and are >=6V, the device will work.

  • 0 in reply to Rick Duncan
    Prodigy 120 points

    Hi Rick,

    Thank you for the confirmation of my measurements. It  did not work for Vm less than 6,9V despite wired-Or (Vm and fixed voltage 8V) on Pin PVDD1.

    I don¨t use Tis InstaSPIN, our customer want to use a specific solution.

    Best regards

    Zbyno

  • 0 in reply to zbyno brudny
    Prodigy 120 points

    Hi Rick,

    I have one last qestion:

    what about to supply DRV8302 into Pin GVDD from external 10-12V. Could be PVDD1 together with Vmot (drains upper Fets) in range 0-48V in this case?

    Best regards

    Zbyno

  • 0 in reply to zbyno brudny
    TI__Guru** 114905 points

    Hi Zbyno,

    Sorry, GVDD is a regulated output not an input.  It is not designed to be driven by an external supply.

    The DRV8302 is designed to run with PVDD1 >=6V.  Attempting to work around this limitation may cause more problems.

    For instance, GVDD is a regulator output creating ~12V. If you try driving it to 10V, the charge pump will continue pumping the voltage to achieve 12V.

    Can you provide more information on the motor you are trying to control? Perhaps there is a better fit in our portfolio.