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Motor Driver similar to L293D

Tony Philip45
Intellectual 755 points
Other Parts Discussed in Thread: L293D, DRV8816, DRV8871, DRV8870, DRV8801, DRV8872, DRV8841, DRV8844

Hi,

I am looking for an Integrated Motor Drive solution for out DC motor. The Specs are simple, the motors are 12 V DC motor with 1.8A RMS current draw. We need bi-directional  control with variable speed (with PWM with up to 255 Resolution).
The mode of operation we re looking forward to is closer to the classic L293D motor driver in terms of PWM speed modulation.

We shortlisted the following single full bridge ICs. DRV8870,DRV8871,DRV8872,DRV8801,DRV8816.    

We also shotlisted these dual full bridge drivers DRV8841,DRV8844 and DRV8816.

One thing Which I couldn't find out is if all of these have the PWM based speed control. I also didnt quite understand whaat it means by current regulation. Isn't PWM enough to have current regulation in all the bridges?

  • 0
    TI__Guru** 114905 points
    Hi Tony,

    There are a few questions that will help narrow your choices.

    What is the input PWM frequency?
    Do you want to preserve the duty cycle at each point? Some of the devices use synchronizers that can cause the output duty cycle to vary a little.
  • 0 in reply to Rick Duncan
    Intellectual 755 points
    The PWM Frequency I am looking for is 500 Hz to max 1K Hz.
    No I m not particular at preserving duty cycle, provided the change is not in the matter of more than 1%.
  • 0 in reply to Tony Philip45
    TI__Guru** 114905 points
    Hi Tony,

    What does the 1% refer to?

    Some of the devices sample the PWM input and can cause the output to be truncated or extended by an internal clock cycle (anywhere from 400ns to 1.6us).

    Assuming that it acceptable, the DRV8871 is a good candidate because of the size.

    If the PWM movement is too much, the DRV8844 does not sample the input. This device preserves the PWM input duty cycle.


    "One thing Which I couldn't find out is if all of these have the PWM based speed control. I also didnt quite understand whaat it means by current regulation. Isn't PWM enough to have current regulation in all the bridges?"

    All the devices have PWM based speed control available via user inputs.

    Many systems run at 100%, and that is where current regulation comes in. The current control is used to limit the stall currents during startup. Once the motor speed increases, the current regulation is no longer needed.
  • 0 in reply to Rick Duncan
    Intellectual 755 points

    Hi Rick ,

    Thanks for the reply.  I also wanted a motor driver with lower current capability ( 2.0A Peak and 1.8A RMS ) current capability similar to the DRV8871's PWM control. This is to drive a smaller load which we have in the system

    Also could please help me understand what is PH/EN mode of control (In DRV 8801) ?

  • 0 in reply to Tony Philip45
    TI__Guru** 114905 points
    Hi Tony,

    The PH/EN interface allows use of one PWM signal routed directly to the EN pin. PH acts as direction, and EN is the PWM input.