Data Sheet

VM
VCP
AOUT1
AOUT2
BOUT1
BOUT2
NFAULT
VINT
AISEN
BISEN
GND
NENBL/AENBL
STEP/BENBL
DIR/BPHASE
M0/APHASE
M1
CONFIG
VREFO
AVREF
BVREF
ADECAY
NSLEEP
BDECAY
VM
Coil A Enable
Coil B Enable
Coil B Direction
Coil A Direction
LOW = SLEEP
VM
10 uf
0.01 uf
2.2 uf
VINT
51K 51K
Stepper
DRV8834
www.ti.com SLVSB19D –FEBRUARY 2012–REVISED MARCH 2015
9.2.2 Phase/Enable Mode Driving a Stepper Motor
Figure 13. Phase/Enable Mode Driving a Stepper Motor
9.2.2.1 Design Requirements
Table 6 lists the design parameters.
Table 6. Design Parameters
PARAMETER REFERENCE EXAMPLE VALUE
Supply voltage V
M
6 V
Motor winding resistance R
L
3.9 Ω
Motor winding inductance I
L
2.9 mH
Motor full step angle θ
step
1.8°/step
Target microstepping level n
m
2 µsteps per step
Target motor speed V 120 RPM
Target full-scale current I
FS
1.25 A
9.2.2.2 Detailed Design Procedure
Phase/enable mode can be used with a simple interface to a controller to operate a stepper motor in full or half
step modes. The decay mode can be set by changing the values of the resistors connected to the ADECAY and
BDECAY pins. The M1 pin is driven to logic high (by connecting to the VINT supply), to allow a zero-current (off)
state when the xENBL pin is set low. Coil current is set by the R
SENSE
resistors. If the sleep function is not
needed, nSLEEP can be connected to VM with an approximate 47-kΩ resistor.
9.2.2.2.1 Stepper Motor Speed
The first step in configuring the DRV8834 requires the desired motor speed and microstepping level. If the target
application requires a constant speed, then a square wave with frequency ƒ
step
must be applied to the STEP pin.
If the target motor start-up speed is too high, the motor will not spin. Make sure that the motor can support the
target speed or implement an acceleration profile to bring the motor up to speed.
For a desired motor speed (v), microstepping level (nm), and motor full step angle (θ
step
),
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