SLOA312 December   2021 DRV8412 , DRV8424 , DRV8426 , DRV8428 , DRV8434 , DRV8436 , DRV8803 , DRV8804 , DRV8805 , DRV8806 , DRV8844 , DRV8847 , DRV8932 , DRV8935 , DRV8955

PRODUCTION DATA  

  1.   Trademarks
  2. 1Introduction
  3. 2Principle of Operation
    1. 2.1 Unipolar Stepper Motors
    2. 2.2 Bipolar Stepper Motors
  4. 3How to Drive Unipolar Stepper Motors with DRV8xxx Drivers
    1. 3.1 Driving Unipolar Motor with Four-channel Low-side Driver
    2. 3.2 Driving a Unipolar Motor with a Bipolar Driver
    3. 3.3 Driving Unipolar Motor with Four-channel Half-Bridge Driver
      1. 3.3.1 Driving in Full-step Mode
        1. 3.3.1.1 Full-step Mode with One Phase ON
        2. 3.3.1.2 Two Phases ON
      2. 3.3.2 Driving in Half-step Mode
      3. 3.3.3 Example Pseudocode
        1. 3.3.3.1 Code for Full-step with One Phase ON
        2. 3.3.3.2 Code for Full-step with Two Phase ON
        3. 3.3.3.3 Code for Half-step
  5. 4References

3.3.1.2 Two Phases ON

In this mode of operation, two low-side MOSFETs are turned on together. This mode results in higher torque than the case when single phase is ON. The truth table and timing diagram for this mode of operation are shown in Table 3-5.

Figure 3-8 and Figure 3-9 show the input and output waveforms when driving a unipolar stepper motor in two phases ON mode with the DRV8935.

Table 3-5 Input and Output Waveforms
INDEX IN1 IN2 IN3 IN4
1 0 0 1 1
2 1 0 0 1
3 1 1 0 0
4 0 1 1 0
GUID-108A2484-1E47-4845-9B76-2500F3B30D36-low.png Figure 3-8 Input PWM signal of DRV8935
GUID-CA079256-B7A4-440F-AF12-74D28959DFC1-low.png Figure 3-9 Output node waveforms of DRV8935