Datasheet

OUT1

OUT2

DCM

ISEN

IN2

Pre-

drive

VCP, VGD

PWM

VREF

OCP

DECAY

DAC

A = 5

IN1

I[4:0]

DRV8842

www.ti.com

SLVSAB8E –MAY 2010–REVISED AUGUST 2013

FUNCTIONAL DESCRIPTION

PWM Motor Drivers

The DRV8842 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 IN1 and IN2 input pins directly control the state of the OUT1 and OUT2 outputs. Either input can also be

used for PWM control of the load. Table 2 shows the logic.

Table 2. H-Bridge Logic

xIN1 xIN2 xOUT1 xOUT2

0 0 L L

0 1 L H

1 0 H L

1 1 H H

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

Current Regulation

The maximum current through the load is regulated by a fixed-frequency PWM current regulation, or current

chopping. When the H-bridge is enabled, current rises through the winding at a rate dependent on the DC

voltage and inductance of the winding. Once the current hits the current chopping threshold, the bridge disables

the current until the beginning of the next PWM cycle.

For DC motors, current regulation is used to limit the start-up and stall current of the motor. Speed control is

typically performed by providing an external PWM signal to the xIN1 or xIN2 input pins.

If the current regulation feature is not needed, it can be disabled by connecting the ISENSE pins directly to

ground and the VREF pins to V3P3.

Product Folder Links: DRV8842