Motor still drawing power when transistor is off

I'm controlling a micro dc motor with this motor driver. In order to power off the motors when they're not in use (while other parts of the project are running) I'm using a transistor and connecting the motor terminals across the diode. It successfully turns off the 12V power supply when LOW, but somehow the motor still turns on a lower speed.

I've tried the transistor set up with the motor and battery directly and all is fine. However, with the addition of the driver I run into this problem. I suspect it's somehow drawing power from the 5V supply at the VDD terminal of the driver. Any thoughts?

The driver itself can power off the motor.

If you want to switch power to the whole driver/motor section then you switch the power to the
drivers, not the motors.

Not nearly enough information for folks to have a reasonable thought.

Things like....

  • How much current do you think is being drawn when the "transistor" is off. And why.
  • What transistor are you referring to? What diode?
  • How is the board wired and what do you have controlling it?

Its kind of like asking.... my car doesn't start .. what do you think.

JazzyJ:
I'm controlling a micro dc motor with this motor driver. In order to power off the motors when they're not in use (while other parts of the project are running) I'm using a transistor and connecting the motor terminals across the diode. It successfully turns off the 12V power supply when LOW, but somehow the motor still turns on a lower speed.

The driver is supposed to supply power to the motor.

If you want to de-energise the motor, then the procedure is to do what is necessary to make the drive to stop outputting voltage and current (ie. power) to the motor.

Hi,

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Thanks.. Tom.. :slight_smile: