DRV8811 Datasheet, PDF (11/19 Pages) Texas Instruments – STEPPER MOTOR CONTROLLER IC

DRV8811
www.ti.com ................................................................................................................................................. SLVS865D – SEPTEMBER 2008 – REVISED JULY 2009
0.6 × VCC
PWM
ON
PWM
OFF
(t_OFF)
Winding
Current
RCx
Voltage
V_BLANK
V_DECAY
0.6 ×
VCC
0.21 × VCC
BLANK
FAST
(t_FD)
DECAY
SLOW
R
VCC
RCx
C
DECAY
QS
QR
VBLANK
PWM_ON
ITRIP
BLANK
0.21 × VCC
PWM_OFF
PWM
SLOW_DECAY
To other PWM
Figure 3. PWM
Microstepping Indexer
Built-in indexer logic in the DRV8811 allows a number of different stepping configurations. The USM1 and USM0
pins are used to configure the stepping format as shown in the table below:
USM1
0
0
1
1
USM0
0
1
0
1
STEP MODE
Full step (2-phase excitation)
1/2 step (1-2 phase excitation)
1/4 step (W1-2 phase excitation)
Eight microsteps/steps
The following table shows the relative current and step directions for different settings of USM1 and USM0. 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 high; if the DIR pin is low the sequence is reversed. Positive current is defined as xOUT1 = positive
with respect to xOUT2.
Note that the home state is 45 degrees. This state is entered at power-up or device reset. The HOMEn output
pin is driven low in this state. In all other states it is driven logic high.
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Product Folder Link(s): DRV8811
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