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DRV8841: DRV8841 Dead time between HS and LS FETs

UmaTatsu
Prodigy 40 points
Part Number: DRV8841
Other Parts Discussed in Thread: DRV8412, , SM72295

Hi,


I'm worrying which IC is better for Step Motor control,  DRV8841 or DRV8412.
In DRV8412 Datesheet, tDT(Dead time between HS and LS FETs) is written.
On the other hand,  tDT is not written in DRV8841 Datesheet.

So, could you tell me tDT of DRV8841?
And, difference between  DRV8841 and DRV8412.

  • 0
    TI__Guru** 114905 points
    Hi user5237878,

    The dead time of the DRV8841 is longer than the deadtime of the DRV8412. We will have to research this to get the information, and it may take up to a week.

    The answer of which one is better really depends on your goals.

    The DRV8841 can control the current using the internal current regulation engine. The DRV8412 requires external current sense amplifiers to control the current.

    The DRV8841 uses a charge pump, while the DRV8412 uses bootstrap.

    The DRV8841 can perform up to 1/4 microstep using the xI1 and xI0 pins, or much higher microstepping using the xVREF pins. The DRV8412 can perform high microstep rates by using the external current sense amplifier.
  • 0 in reply to Rick Duncan
    TI__Mastermind 21805 points

    Hello user5237878,

    Can you provide:

    • target supply voltage
    • stepper motor RMS current
    • target microstepping level

    Thanks,

    Matt

  • 0
    TI__Expert 7300 points

    Hi user5237878,

    The rising deadtime  of DRV8841 is about 528ns typically.

    The falling deadtime of DRV8841 is about 600ns typically.

    Thank you.

  • 0 in reply to Rick Duncan
    Prodigy 40 points
    Hi, Rick Duncan
    Thanks for your reply.

    \The DRV8841 uses a charge pump, while the DRV8412 uses bootstrap.
    ->This is important difference. If I select DRV8412, Bootstrap needs another Power Circuit and PCB cost increase.
    So, Peak or RMS Current is permitted, I select DRV8841. (Current is not confirmed.)
    I'll try.
  • 0 in reply to Matt Hein
    Prodigy 40 points
    Hi, Matt.

    Soory, Voltage and RMS current is not confirmed. I'm just trying.
  • 0 in reply to Betty Guo
    Prodigy 40 points
    Hi, Betty
    Thanks for your aply.
    Above graph is good for me. I'm trying to replace IC which is similor to the SM72295 with more Low voltage IC.