Datasheet

OUT1

OUT2

DCM

ISEN

PHASE

Pre-

drive

VCP, VGD

PWM

VREF

OCP

DECAY

DAC

A = 5

ENBL

I[4:0]

DRV8840

www.ti.com

SLVSAB7C –MAY 2010–REVISED AUGUST 2013

FUNCTIONAL DESCRIPTION

PWM Motor Driver

The DRV8840 contains one H-bridge motor driver with current-control PWM circuitry. A block diagram of the

motor control circuitry is shown in Figure 1.

Figure 1. Motor Control Circuitry

Note that there are multiple VM, ISEN, OUT, and VREF pins. All like-named pins must be connected together on

the PCB.

Bridge Control

The PHASE input pin controls the direction of current flow through the H-bridge, and hence the direction of

rotation of a DC motor. The ENBL input pin enables the H-bridge outputs when active high, and can also be

used for PWM speed control of the motor. Note that the state of the DECAY pin selects the behavior of the

bridge when ENBL = 0, allowing the selection of slow decay (brake) or fast decay (coast). Table 2 shows the

logic.

Table 2. H-Bridge Logic

DECAY ENBL PHASE OUT1 OUT2

0 0 X L L

1 0 X Z Z

X 1 1 H L

X 1 0 L H

The control inputs have internal pulldown resistors of approximately 100 kΩ.

Product Folder Links: DRV8840