rikardjh
Newbie level 1
Add DC offset to a PWM motor control circuit
Hi! I have a fairly simple motor controller controlling a DC motor. It's just a MCU feeding a pwm signal through a transistor, much like this one: https://www.robotroom.com/PWM/MotorSpeedControlSchematic.gif
However, I need the motor to keep running when the pwm signal is zeroed. What I have now is roughly 0-5v amplified to 0-Nv, but what I need is to add a DC offset so that the motor is controlled from ~4-Nv. I could of course just adjust the PWM signal but I would prefer to keep the resolution of the PWM signal.
Could I just add a DC offset with a voltage divider after the amplification stage? I'm guessing an op-amp would not be good at handling the current draw and possible flyback from the motor so I'm thinking a op-amp summing circuit is out..
Thank you!
Hi! I have a fairly simple motor controller controlling a DC motor. It's just a MCU feeding a pwm signal through a transistor, much like this one: https://www.robotroom.com/PWM/MotorSpeedControlSchematic.gif
However, I need the motor to keep running when the pwm signal is zeroed. What I have now is roughly 0-5v amplified to 0-Nv, but what I need is to add a DC offset so that the motor is controlled from ~4-Nv. I could of course just adjust the PWM signal but I would prefer to keep the resolution of the PWM signal.
Could I just add a DC offset with a voltage divider after the amplification stage? I'm guessing an op-amp would not be good at handling the current draw and possible flyback from the motor so I'm thinking a op-amp summing circuit is out..
Thank you!
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