A OU T 1

A OU T2

BOU T1

B OU T2

Step

Motor

VM

VM

A IS EN

B ISEN

APH A SE

Pre-

drive

Pre-

drive

VC P, VGD

VM

VM

+

-

PW M

V CP, VGD

+

-

PW M

A BVR EF

OC P

OC P

OC P

OC P

A BD EC A Y

B EN BL

DAC

DAC

A = 5

A = 5

A I[2:0]

B I[2:0]

3

3

AEN B L

BPH A SE

A I[2:0]

3

From Indexer Logic

DRV8821

www.ti.com

SLVS912E – JANUARY 2009 – REVISED AUGUST 2010

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.

Figure 1. Block Diagram

Note that there are multiple VM motor power supply pins. All VM pins must be connected together to the motor

supply voltage.

Copyright © 2009–2010, Texas Instruments Incorporated

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Product Folder Link(s): DRV8821