DRV8821_15 Datasheet, PDF (8/23 Pages) Texas Instruments – DUAL STEPPER MOTOR CONTROLLER/DRIVER

DRV8821
SLVS912I – JANUARY 2009 – REVISED JANUARY 2014
FUNCTIONAL DESCRIPTION
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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).
VCP, VGD
OCP
VM
VM
From Indexer Logic
AEN B L
APH A SE
A BD EC A Y
A I[2:0]
A I[2:0]
Pre-
driv e
PW M
3
DAC
3
OCP
-
+
A =5
A OU T1
A OU T2
A IS EN
Step
Motor
A BVR EF
B EN BL
BPH A SE
B I[2:0]
V CP, VGD
OCP
Pre-
driv e
PW M
DAC
3
OCP
-
+
A =5
VM
VM
BOU T1
B OU T2
BISEN
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.
8
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