Stepper Motor Overview
The stepper motor has a rotor with permanent magnets mounted on it, while the stator has a minimum of two windings. When the rotor magnet aligns with the stator winding, the second winding is energized. The two windings are turned on and off alternately; this causes the motor to lock on to the desired step position. The direction of the current through the winding can also be reversed.
In a stepper motor with two stator windings, there are clearly four steps, separated by 90 degrees. A stepper motor can be controlled precisely as it moves in steps, depending on the pulses provided to the stator windings.
The speed control of a stepper motor is achieved by the pulse frequency provided to the windings, while the direction of rotation can be changed by reversing pulse sequences. The pole pieces inside the motor have many teeth, which help in aligning the rotor position relative to the stator. Some stepper motors also have teeth on the stator poles.
Stepper motors can be controlled in full steps, half steps or micro steps, depending on the control techniques used. Simple square pulses can control the motor in full steps, while advanced control techniques such as pulse-width modulation (PWM) are used in micro stepping.
Microcontrollers
A basic MSP430 MCU in conjunction with a stepper control driver IC such as a DRV8412 can provide full step or up to 16 micro steps at a very low cost. More complex control of stepper motors is possible with Stellaris™ or C2000™ MCUs. On-board peripherals such as ADCs and PWMs create a highly integrated solution to meet all application requirements with stepper motors.
Interface/Connectivity
Traditional analog RS-232/RS-485 interfaces remain popular choices for motor control applications. Looking forward, designers are integrating mainstream interfaces such as Ethernet, USB and CAN into their products.
TI is committed to providing solutions for both traditional and emerging industrial interfaces. For example, TI recently introduced the ISO1050, the world's first isolated CAN transceiver.
Power Management
Texas Instruments offers power management IC solutions ranging from standard ICs to high-performance, plug-in, power-brick, digital-power MOSFETs and integrated power modules.
From AC/DC and DC/DC power supplies, linear regulators and non-isolated switching DC/DC regulators to PMICs and power and display solutions, Texas Instruments power management IC solutions can help you complete your project.
Recommended Resources
Overview of TI Motor Control Resources
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