DRV8886AT Datasheet, PDF (14/40 Pages) Texas Instruments – 2-A Stepper Motor Driver With Integrated Current Sense and AutoTune Technology

DRV8886AT
SLVSDO1 – JANUARY 2017
www.ti.com
7.3.2 PWM Motor Drivers
The DRV8886AT device has drivers for two full H-bridges to drive the two windings of a bipolar stepper motor.
Figure 13 shows a block diagram of the circuitry.
VM
xOUT1
Microstepping and
Current Regulation
Logic
Gate
Drivers
Current
Sense
VM
xOUT2
Current
Sense
PGND
Figure 13. PWM Motor Driver Block Diagram
7.3.3 Microstepping Indexer
Built-in indexer logic in the DRV8886AT device allows a number of different step modes. The M1 and M0 pins
are used to configure the step mode as shown in Table 2.
Table 2. Microstepping Settings
M1
M0
STEP MODE
0
0
Full step (2-phase excitation) with 71% current
0
1
1/16 step
1
0
1/2 step
1
1
1/4 step
0
Z
1/8 step
1
Z
Non-circular 1/2 step
Table 3 shows the relative current and step directions for full-step through 1/16-step operation. The AOUT
current is the sine of the electrical angle and the BOUT current is the cosine of the electrical angle. Positive
current is defined as current flowing from the xOUT1 pin to the xOUT2 pin while driving.
At each rising edge of the STEP input the indexer travels to the next state in the table. The direction is shown
with the DIR pin logic high. If the DIR pin is logic low, the sequence is reversed.
On power-up or when exiting sleep mode, keep the STEP pin logic low, otherwise the indexer advances one
step.
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