FORWARD

REVERSE

OUT1

OUT2

2

1

2

2

Forward drive

Slow decay (brake)

VM

1

OUT1

OUT2

2

1

2

2

Reverse drive

Slow decay (brake)

VM

1

3

3 High-Z (coast)

3 High-Z (coast)

3

8

DRV8872

SLVSCZ0B – AUGUST 2015 – REVISED JANUARY 2016

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Product Folder Links: DRV8872

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7.3 Feature Description

7.3.1 Bridge Control

The DRV8872 output consists of four N-channel MOSFETs that are designed to drive high current. They are

controlled by the two logic inputs IN1 and IN2, according to Table 1.

Table 1. H-Bridge Control

IN1

IN2

OUT1

OUT2

DESCRIPTION

0

0

High-Z

High-Z

Coast; H-bridge disabled to High-Z (sleep entered after 1 ms)

0

1

L

H

Reverse (current OUT2

→ OUT1)

1

0

H

L

Forward (current OUT1

→ OUT2)

1

1

L

L

Brake; low-side slow decay

The inputs can be set to static voltages for 100% duty cycle drive, or they can be pulse-width modulated (PWM)

for variable motor speed. When using PWM, it typically works best to switch between driving and braking. For

example, to drive a motor forward with 50% of its max RPM, IN1 = 1 and IN2 = 0 during the driving period, and

IN1 = 1 and IN2 = 1 during the other period. Alternatively, the coast mode (IN1 = 0, IN2 = 0) for fast current

decay is also available. The input pins can be powered before VM is applied.

Figure 4. H-Bridge Current Paths

7.3.2 Sleep Mode

up while both inputs are low, sleep mode is immediately entered. After IN1 or IN2 are high for at least 5 µs, the

7.3.3 Current Regulation

The DRV8872 limits the output current based on the resistance of an external sense resistor on pin ISEN,

according to this equation: