SLVA767A September   2016  – December 2016 SN75469 , TPL7407L , TPL9201 , ULN2003A , ULN2003B , ULN2003V12 , ULN2004A , ULQ2003A , ULQ2003A-Q1 , ULQ2004A , ULQ2004A-Q1


  1.   Stepper Motor Driving With Peripheral Drivers (Driver ICs)
    1.     Trademarks
    2. 1 Peripheral Driver (Driver IC) Overview
    3. 2 Stepper Motors
      1. 2.1 Unipolar Stepper Motors
      2. 2.2 Bipolar Stepper Motors
    4. 3 Stepper Motor Driving Overview
      1. 3.1 Unipolar Stepper Motor Driving Block Diagram
      2. 3.2 Detailed Design Considerations
      3. 3.3 Bipolar Stepper Motor Driving Block Diagram
      4. 3.4 Detailed Design Considerations
    5. 4 Stepper Motor Driving Patterns
      1. 4.1 Wave Drive Operation
      2. 4.2 Full-Step Operation
      3. 4.3 Half-Step Operation

Unipolar Stepper Motors

Unipolar stepper motors only require current to flow in a single direction, which makes hardware design simpler because only a low side switch/driver is required (a switch to conduct current to ground from the component - see Figure 1). The high-side of the motor phase is connected directly to the supply voltage without a switch. Unipolar stepper motors can be driven by a stepper motor sequence using a peripheral driver - ULN2003A and TPL7407L are examples of devices that can drive these stepper motors. See Section 3.1 for additional information regarding how to connect a stepper motor to a peripheral driver.

Low-High-Side-Switches.gifFigure 1. Low-Side and High-Side Switches/Drivers

Unipolar stepper motors come in three primary wiring configurations, 5-wire, 6-wire, and 8-wire, where 5-wire and 6-wire stepper motors are the most common. In a 5-wire stepper motor the center tap connections are shorted together internally as shown in Figure 2. In a 6-wire stepper motor the center tap connections are separate connections as shown in Figure 3. A 6-wire stepper motor can effectively act as a 5-wire stepper motor by connecting the two center tap wires.

Stepper_5pin.gifFigure 2. 5-Wire Unipolar Stepper Motor
Stepper_6pin.gifFigure 3. 6-Wire Unipolar Stepper Motor