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DRV8306: IDRIVE & Retry mode

Avinash Maurya
Prodigy 20 points
Part Number: DRV8306

As given in a datasheet of DRV8306 38-V Brushless DC Motor Controller datasheet (Rev. A), section:8.2.1.2.2 IDRIVE Configuration,

 

The Qgd of our STL36DN6F7 is 2.1nC, T rise = 3.25ns, T fall = 3.95ns.

Given this how to calculate IDRIVE input mode voltage? It is beyond the scope.

 

Given tr & tf on section 8.2.1.1, table 4 is an example value or what?

 

We are using RSEN = 0.03 Ohm, calculated as per 8A, RDS= 27mOhm requirement.

 

It seems the driver is going into retry mode repeatedly.

FYI, VDS = 18kOhm to GND.

  • 0
    TI__Mastermind 21805 points

    Hello,

    Thanks for your question. Please set IDRIVE such that Qgd/IDRIVE = 100-300ns. In your case, I recommend the lowest setting of 15mA (~140ns rise time)

    Table 4 is an example using some example design parameters.

    Can you share your schematic? Can you capture an oscilloscope shot of the ISEN pin, the SHx pin, and nFAULT pin to see if it is tripping the cycle-by-cycle current limitation?

    Thanks,

    Matt