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BLDC motor as a stepper.

ken thompson
Intellectual 630 points
Other Parts Discussed in Thread: DRV8320, DRV8884

Is there a driver capable of using a 3 phase BLDC motor as a stepper? It would obviously have only six half steps instead of the eight half steps of a conventional stepper motor.  The BLDC motor target has a gear train output so it will have a resolution similar to a conventional large stepper.

  • 0
    TI__Intellectual 2600 points
    Ken,

    If I understand correctly you are wanting to control the 6 different commutation states and potentially stop at a particular state?

    I would suggest looking at DRV8320 which is a pre-driver but allows you to control the commutation states with either 3 or 6 inputs.

    The DRV10x series of parts which is what MD-IMC supports have the control integrated and thus no way to control which commutation states are active.

    Thanks,
    Brian
  • 0 in reply to Brian Schmidt
    Intellectual 630 points
    A predriver is not needed. Looking for an integrated driver, 3ph. The motor is only 5 to 8 v, 20mA per phase. Need the interface of the DRV8884, step and direction, with micro-steppping, but 6 phases per half step instead of the 8 phs. A number of parts can be found in China, but its China.
  • 0 in reply to ken thompson
    Intellectual 630 points

    Here is the motor we are talking about. it is intended to drive mechanical pointers for instrumentation. Just do not have the luxury of a uP or FPGA.

    Analog voltage in is compared to the voltage out from a DAC. The DAC input is from an up/down counter, clocked continuously with the up/down controlled by the comparator. The same up/down and clocking then runs an indexed driver for the stepper. DRV8884 works fine for the large 8ph half step motors. Need a similar part to run this small 6ph half step and with the indexed micro-stepping too.

    X25_xxx_03_SP_E(1).pdf

  • 0 in reply to ken thompson
    TI__Mastermind 18900 points
    Hey Ken,

    As Brian mentioned, the DRV10x series does not allow control over the commutation states and the series of parts are the only integrated motor drivers that TI has to offer. As a result, it looks like we cannot meet your application requirements unless you would like to consider some gate drivers as the DRV8320. If you have questions specifically about the DRV8884, please make another thread.

    Thank you,
    -Cole