dcmotorstepper-driver
I only have a stepper motor driver TB6600 available at the moment, can I use it for control of a a brushed dc motor? I think it should work as I could use PWM. I also want to be able to reverse direction. I looked through the datasheets and online tutorials but I could not find out how to connect the pins and what mode to select.
My question: Is it possible to control a dc brushed motor with TB6600, and if yes, how?
Yes, approximately. I wouldn't PWM the direction pin though, as that would likely toggle between two motors.
To drive a motor unidirectionally, you only need one switch, but to drive it bi-directionally you need 4, usually in an H-bridge configuration. Low side switches tend to be N-type semiconductors which are more efficient than P-side, so you probably want to connect each of your motors between the supply and one of the switched output, and set the output high to disable the motor.
You'll have to pull the data sheet and work out the details of the control signals; you may find that you cannot run the motors with full independence.
You might also look at using N-type logic level gate MOSFETS alone, one per motor. But selecting and applying those can be a bit more involved than just using a chip like the TB6612.
The chopper has a sense resistor that is used to measure the current. When the current is below setpoint, then the transistor is ON. If the current rises above the setpoint then the transistors are OFF. This so called chopper, it is a two position controller ON/OFF.
As you can see from the picture, the voltage is pulsed, meanwhile the current is continuous and it is flipping around setpoint value.
Any assumptions regarding PWM in your question is wrong. Even when outputting a PWM signal, the current is always continuous, not pulsed.
The motor doesn't change the resistance, it rather builds up the back EMF voltage when it is spinning. So that's why you need 7.65V for 1.7A at standstill, and you might need 17.65V for 1.7A when the motor generates 10V.
Best Answer
A brushed motor requires a DC voltage to reach full speed and start with full torque then uses it’s armature to self commutate which also results in large BEMF energy released during commutation with only 2 wires to input mux’d to each coil.
A stepper driver always gives 50% duty cycle output as it commutates 1 of 4 phases or full steps to 2 coils and only gives DC when stopped.
Therefore it is incompatible to control velocity with a position control stepper driver.