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

3.1 Driving Unipolar Motor with Four-channel Low-side Driver

To drive a unipolar stepper motor with a single supply connection, only four low side MOSFETs and circulating diodes are needed. The schematic with such a low-side MOSFET driver is shown in Figure 3-1.

GUID-ED876E91-0C03-4015-AA32-F9B6235FAE77-low.jpgFigure 3-1 Driving Unipolar Stepper with Low-side Driver

DRV8803, DRV8804, DRV8805 and DRV8806 from Texas Instruments are examples of such drivers meant to drive unipolar motors. These drivers are rated up to 60 V supply voltage, available in PWM, STEP/DIR or serial interfaces, and can deliver up to 2 A per channel.

Table 3-1 summarizes the major features of these four drivers.

Table 3-1 Comparison among DRV880x Low-side Drivers
DriverDRV8803DRV8804DRV8805DRV8806
Maximum Supply Voltage60 V60 V60 V40 V
MOSFET RDS (ON)0.5 Ω0.5 Ω0.5 Ω0.5 Ω
Input InterfacePWM (EN/INx)Serial InterfaceSTEP/DIR with full-step, half-step and wave driveSerial Interface
Package OptionsSOIC-20, HTSSOP-16SOIC-20, HTSSOP-16SOIC-20, HTSSOP-16HTSSOP-16
Maximum Continuous Output Current1.5 A (SOIC), 2 A (HTSSOP)1.5 A (SOIC), 2 A (HTSSOP)1.5 A (SOIC), 2 A (HTSSOP)2 A
Integrated Clamp DiodesYesYesYesYes
Protection FeaturesOvercurrent, Short circuit, Undervoltage, OvertemperatureOvercurrent, Short circuit, Undervoltage, OvertemperatureOvercurrent, Short circuit, Undervoltage, OvertemperatureOvercurrent, Short circuit, Undervoltage, Overtemperature, Open load detection

A typical application schematic with the DRV8803 is shown in Figure 3-2.

GUID-611BA404-CE69-4CC8-B787-5903A41BE881-low.pngFigure 3-2 Unipolar Stepper Schematic with DRV8803