Datasheet

AOU T1
AOU T2
BOU T1
BOU T2
Step
Motor
VM
VM
AIS EN
BISEN
APH ASE
Pre-
drive
Pre-
drive
VCP, VGD
VM
VM
+
-
PWM
V CP, VGD
+
-
PWM
ABVREF
OCP
OCP
OCP
OCP
ABDECA Y
BEN BL
DAC
DAC
A = 5
A = 5
AI[2:0]
BI[2:0]
3
3
AEN BL
BPH ASE
AI[2:0]
3
From Indexer Logic
DRV8821
SLVS912H –JANUARY 2009–REVISED AUGUST 2013 www.ti.com
FUNCTIONAL DESCRIPTION
PWM Motor Drivers
The DRV8821 contains four H-bridge motor drivers with current-control PWM circuitry. A block diagram showing
drivers A and B of the motor control circuitry (as typically used to drive a bipolar stepper motor) is shown below.
Drivers C and D are the same as A and B (though the R
ds(on)
of the output FETs is different).
Figure 2. Block Diagram
Note that there are multiple VM motor power supply pins. All VM pins must be connected together to the motor
supply voltage.
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