xOUT1

xOUT 2

VM

xISEN

xIN2

Pre-

drive

VCP, VINT

VM

+

-

PWM

OCP

OCP

xIN1

REF (200mV)

DCM

Optional

DRV8833

www.ti.com

SLVSAR1E – JANUARY 2011 – REVISED JULY 2015

7.3 Feature Description

7.3.1 Fixed-Frequency PWM Motor Drivers

DRV8833 contains two identical H-bridge motor drivers with current-control PWM circuitry. Figure 5 shows a

block diagram of the circuitry.

Figure 5. Motor Control Circuitry

7.3.2 Bridge Control and Decay Modes

The AIN1 and AIN2 input pins control the state of the AOUT1 and AOUT2 outputs; similarly, the BIN1 and BIN2

input pins control the state of the BOUT1 and BOUT2 outputs. Table 1 shows the logic.

Table 1. H-Bridge Logic

xIN1

xIN2

xOUT1

xOUT2

FUNCTION

Coast/fast

0

0

Z

Z

decay

0

1

L

H

Reverse

1

0

H

L

Forward

Brake/slow

1

1

L

L

decay

The inputs can also be used for PWM control of the motor speed. When controlling a winding with PWM, when

the drive current is interrupted, the inductive nature of the motor requires that the current must continue to flow.

This is called recirculation current. To handle this recirculation current, the H-bridge can operate in two different

states: fast decay or slow decay. In fast decay mode, the H-bridge is disabled and recirculation current flows

through the body diodes; in slow decay, the motor winding is shorted.

To PWM using fast decay, the PWM signal is applied to one xIN pin while the other is held low; to use slow

decay, one xIN pin is held high.

Table 2. PWM Control of Motor Speed

xIN1

xIN2

FUNCTION

PWM

0

Forward PWM, fast decay

1

PWM

Forward PWM, slow decay

0

PWM

Reverse PWM, fast decay

PWM

1

Reverse PWM, slow decay

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