DRV8880_15 Datasheet, PDF (15/48 Pages) Texas Instruments – DRV8880 2-A Stepper Motor Driver With AutoTune™

www.ti.com
DRV8880
SLVSD18A – JUNE 2015 – REVISED JULY 2015
Feature Description (continued)
7.3.2 PWM Motor Drivers
The DRV8880 contains drivers for two full H-bridges. A block diagram of the circuitry is shown in Figure 13.
VM
Device
Logic
PWM
Logic
Gate _VM
Drive
xOUT1
xOUT2
+
Step
Motor
-
+-
+
-
VREF
TRQ[1:0]
4
SINE DAC
1/Av
xISEN
R_SENSE
Figure 13. PWM Motor Driver Block Diagram
7.3.3 Microstepping Indexer
Built-in indexer logic in the DRV8880 allows a number of different stepping configurations. The Mx pins are used
to configure the stepping format as shown in Table 1.
Table 1. Microstepping Settings
M1
M0
STEP MODE
0
0
Full step (2-phase excitation) with 71%
current
0
1
Non-circular 1/2 step
1
0
1/2 step
1
1
1/4 step
0
Z
1/8 step
1
Z
1/16 step
Z
0
Reserved
Z
1
Reserved
Z
Z
Reserved
Table 2 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; BOUT current is the cosine of the electrical angle. Positive current is
defined as current flowing from xOUT1 to xOUT2 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.
Note that if the step mode is changed while stepping, the indexer will advance to the next valid state for the new
MODE setting at the rising edge of STEP.
The home state is an electrical angle of 45°. This state is entered after power-up, after exiting logic undervoltage
lockout, or after exiting sleep mode. This is shown in Table 2 with the highlighted row.
Copyright © 2015, Texas Instruments Incorporated
Product Folder Links: DRV8880
Submit Documentation Feedback
15