DRV8821_16 Datasheet, PDF (10/32 Pages) Texas Instruments – Dual Stepper Motor Controller and Driver

DRV8821
SLVS912J – JANUARY 2009 – REVISED JANUARY 2016
7.2 Functional Block Diagram
0.47µF
6.3V
V3P3
Dig.
VCC
3.3V
Re gulator
ABVREF
ABSTEP
ABDIR
ABENBLn
ABU SM0
ABUSM1
ABDECAY
ABRESETn
CDSTEP
CDDIR
CDENBLn
CDUSM0
CDUSM1
CD DEC AY
CDRESETn
I ndexer
Logic
CDVREF
PWM H-b ridge
driver A
PWM H-bridge
driver B
PWM H-bridge
driver C
PWM H-bridge
driver D
Charge
Pump and
Gat e Drive
Regulator
VGD VCP
·
CP1
0.01µF
35V
CP2
+24
VCP
0. 1µF
+24
16 V
VM
·
0.1µF, 35V
AOUT1
AOUT2
AISEN
+24
VM
BOUT1
·
0.1µF, 35V
BOUT2
BISEN
+24
VM
COUT1
·
0.1µF, 35V
COUT2
CI SEN
+24
VM
DOUT1
·
0.1µF, 35V
DOUT2
DISEN
Step
Motor
Step
Motor
OCP
Thermal
Shut down
Oscillator
UVLO
RESET
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GND
7.3 Feature Description
7.3.1 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).
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