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DRV8821: Applying TIDA-01227 reference design to DRV8821

Part Number: DRV8821
Other Parts Discussed in Thread: TIDA-01227, DRV8711,

Hi,

I want to design High Voltage Stepper Driver as in TIDA-01227 reference design but for two stepper motors. 

Is it possible to apply same analogy used for DRV8711 to DRV8821 dual motor driver?

Thanks,  

  • Hi Uguryildiz,

    The connections shown in TIDA-01227 (a stepper motor controller using external FETs) do not apply to stepper drivers with integrated FETS. It is not recommended to use stepper motors with integrated FETs to control external gate drivers.

    There are several issues when dealing with internal FETs vs gate drivers:

    1) The two internal HS/LS gate signals are not available. This means an inverter is needed to provide proper inputs to the external gate driver.

    2) XXENBLn should be included in the logic at the gate driver to disable both the HI and LI inputs.

    3) When in fast decay, the outputs are disabled as the current approaches zero and begins to reverses. The outputs are disabled which can create an unknown voltage at the input of the external gate driver. This could lead to unexpected results at low voltages.

    4) Overcurrent protection (OCP) is disabled since the current does not flow through the internal FETs. This is true for TIDA-01227 also.

  • Hi Rick,

    Because all other stepper drivers include internal FETs, then the only one-chip solution for two motors from TI seems to use double DRV8711. 

    If not, please recommend an alternative. 

    Thanks.

    Ugur

  • Hi Ugur,

    Two DRV8711s plus external FETs is the recommended solution.