How does ULN2003 drive 5V stepper motor
ULN2003 is a non-gate circuit consisting of 7 units. The anodes of each diode are connected to the collectors of the Darlington tubes. When used for inductive load, the pin is connected to the positive pole of the load power supply and acts as a freewheeling flow. (In the inductive load, a large back electromotive force is generated after the circuit is disconnected. To prevent damage to the Darlington tube, the diode is connected to the reverse phase. The path is converted to current).
Stepper motor is an open-loop control motor that converts electrical pulse signals into angular displacement or linear displacement. It is the main actuator in modern digital program control systems and is widely used. In the case of non-overload, the speed and stop position of the motor depend only on the frequency of the pulse signal and the number of pulses, and are not affected by the load change. When the stepper driver receives a pulse signal, it drives the stepper motor. The set direction is rotated by a fixed angle called the "step angle" whose rotation is performed step by step at a fixed angle. The angular displacement can be controlled by controlling the number of pulses to achieve the purpose of accurate positioning. At the same time, the speed and acceleration of the motor rotation can be controlled by controlling the pulse frequency, thereby achieving the purpose of speed regulation.
How does ULN2003 drive 5V stepper motor
The first stepping motor needs a large driving current, so the direct use of the single chip often has insufficient pin current, and the general 3.3V single chip cannot drive the 5V stepping motor, so circuit conversion is required. The ULN2003 chip is used to drive the stepper motor. ULN2003 acts as a current amplifier and also makes the drive voltage 5V. In addition to using ULN2003, you can build your own circuit with a triode. The principle is similar to the internal structure of ULN2003.
That is, when the stepper motor is to be operated, how to give a pulse and let the motor continuously move. Ps: If the wrong pulse is given, it may turn left a few times and turn back. The picture below shows the phase sequence of a small motor.
