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DRV8837: Need Motor Driver to Drive DC-Iris

Vernon Kong
Prodigy 70 points
Part Number: DRV8837

Tool/software:

Hi,

I have a lens module in which the lens' aperture is controlled via a DC-Iris motor (2 Iris Blades mechanism galvanometer drive). I wish to control the lens to fully open, partially open i.e. (25%,50%,75%) and fully close. Could you please recommend a suitable motor driver that can accomplish these functions?

My DC-Iris has 4 wires: 1. Driving+ 2. Driving - 3.Stopping+  4. Stopping-. I have a Panasonic AN41908A demo-kit that can perform above function through the Iris Drive internal module but I want to explore other alternative parts because there is lack of documentation from Panasonic explaining how to configure the IC to properly drive the driving and stopping coil of DC-Iris. I looking at the datasheet of TI DRV8837 but there is only two wires available to connect to the motor (my DC-Iris has 4 wires)

Thank you

  • 0
    TI__Mastermind 23411 points

    Vernon, 

    Our team is not familiar with this type of drive.  Can you measure the voltage/current direction on the 4 wires when driving it?  Do you have an oscilloscope or logic analyzer so you can see if it's using PWM or what? The naming scheme doesn't make much sense to me as either two BDCs or a stepper motor.  

    The Panasonic chip you linked has an H-bridge for the IRIS and two stepper motor outputs.  So the iris could be connected to the stepper motor output in which case you would need a stepper driver like DRV8434 (Pololu breakout).  If it's a single brushed DC motor it wouldn't need 4 wires.  

  • 0 in reply to Jacob Thompson
    TI__Mastermind 44325 points

    Hi Vernon,

    My guess, the Stopping+ and Stopping- could be hall sensor iris position feedback. I see the Panasonic device has hall sensor inputs. Assuming this is the case, you should interface these two pins to the MCU controlling the DRV8837 and stop the driver (brake) when the position is reached. This will allow you to achieve the desired positions. 

    Regards, Murugavel