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DRV8873-Q1: Driver Motor IC to drive power 12V DC motor

d_zero
Genius 4685 points
Part Number: DRV8873-Q1
Other Parts Discussed in Thread: DRV8702-Q1, DRV8703-Q1, TIDA-01389, TIDA-00480

Dear *,

I have a DC motor with specification:

Voltage rating :12V

No load current <= 3A

Load Rating <= 7A

Locked current <=20A

1) Do TI have an IC integrated driver to drive this kind of motor ( or do you have a controller and then i use discrete mosfet) ?

2) One general question: I looked at the TI dc motor drivers and they all have VM pin ( voltage to motor).

So if my motor is 12V, and i have 12V battery, if i apply 12V to the VM pin of the driver ic -> then a lower voltage will be on the motor, is this right?

eg. VM pin is 12V and the current for load the motor is 7A -> the voltage on motor Vm = VM- I*rdson(H-fet)-I*rdson(L-fet) ??

What is the best way to calculate and design the voltage of VM pin in order to get 12V on the motor rails?

Best Regards. 

  • 0
    TI__Guru** 114905 points

    Hi d_zero,

    1) Do TI have an IC integrated driver to drive this kind of motor ( or do you have a controller and then i use discrete mosfet) ?

    >>> Assuming you do not need an automotive device, there is an integrated device that could work. The DRV8432 used in parallel mode can provide the desired current.

    >>> In general, you are better off with a gate driver like the DRV8702-Q1 or DRV8703-Q1. These devices allow you to pair the RDSon and gate charge of the FETs to your needs.

    2) One general question: I looked at the TI dc motor drivers and they all have VM pin ( voltage to motor).

    So if my motor is 12V, and i have 12V battery, if i apply 12V to the VM pin of the driver ic -> then a lower voltage will be on the motor, is this right?

    eg. VM pin is 12V and the current for load the motor is 7A -> the voltage on motor Vm = VM- I*rdson(H-fet)-I*rdson(L-fet) ??

    What is the best way to calculate and design the voltage of VM pin in order to get 12V on the motor rails?

    >>> You are correct. The RDSon of the FETs lower the motor voltage, as does the voltage across the current sense resistor. Because of the voltage drops, you will not achieve 12V on the motor, but you can approach 12V with low RDSon FETs. Your search for high performance FETs can start here: http://www.ti.com/power-management/mosfet/n-channel-mosfet-transistor/overview.html 

  • 0 in reply to Rick Duncan
    Genius 4685 points

    Dear Rick,

    thank you for the replay. Those are great info. I have some more question.

    1) Regarding DRV8703-Q. I see that TI has TIDA-01389 - Small-Footprint Sunroof Motor Module Reference Design.

    In the design it say a Brushed DC motor (BDC) is used and the hall sensors are used to determine speed and position of the BDC.

    a) Can you tell me what kind of BDC is used on TIDA-01389?

    b) it is possible to use BDC that has permanent magnet in stator ?

    c) can we use a power window motor like this with the hall sensors that are on TIDA-01389?:

    2) What kind of hall sensors can i use with the power window DC motor to determine the speed and the position of the motor?

    3) Is in TIDA-00480 Design Automotive Hall Sensor Rotary Encoder also an BDC used? What kind of BDC is used?

    Best Regards.