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Do I need Isolate Drv8711 and MicroController from Each Other?

yasin idiz
Prodigy 130 points
Other Parts Discussed in Thread: DRV8711, DRV8711EVM

Hello,

We are planing to use DRV8711 drivers with TivaC uCs. But I need some answers before schema.

1) Do I need to isolate Power Line of Microcontroller and DRV8711 from each other with an Isolator. (Seperated Grounds?)

2) Do i need Digital Signal Isolating for Step,DIR and Communication Lines?

3)I have DRV8711EVM and I ve seen there is nothing to isolate. This can be trustable?

4) Can i use Regulated 5V from DRV8711 5VOut pin to supply TivaC(Sure after regulating it 3.3)

  • 0
    TI__Mastermind 21320 points

    Hello,

    Items 1,2 and 3: Whether or not you require isolation is dependent on your system needs. If you have highly sensistive signal/control lines, etc then you may need to take steps to isolate the switching power stage from these. Proper routing of switching lines and ground loops in PCB design can go a long way to isolate switching noise from other components in the system without full on isolation.

    Item 4: Yes. The DRV8711 5V output is capable of 10mA.

  • 0 in reply to Nicholas Oborny
    Prodigy 130 points

    Thanks Nicholas.

    side of DRV8711, for digital signals which signal line i can use for + reference? is DRV8711 5V output line  ideal to use as positive reference for digital signals while isolating with Digital Isolator IC? in other words can i use this(DRV8711 5V out) as digital isolator VDD2 for DRV8711 side.

  • 0 in reply to yasin idiz
    TI__Mastermind 21320 points

    I do not see any immediete issues with this configuration. The DRV8711 inputs are 5V capable. You would want to pull all of the open drain outputs on the DRV8711 to this rail as well.

  • 0 in reply to Nicholas Oborny
    Prodigy 130 points

    indeed my aim is to protect uC from ground oscillations may come from Motor side. DRV8711 is capable to absorbe this because of high working voltage range. But uC Max. rate to absorbe 6 - 6.5V. This is why i am trying to seperate their grounds.