Technical Note

8/15

BD622□ Series

www.rohm.com

2010.07 - Rev.D

© 2010 ROHM Co., Ltd. All rights reserved.

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Functional descriptions

1) Operation modes

Table 6 Logic table

FIN

RIN

VREF

OUT1

OUT2

Operation

a

L

L

X

Hi-Z*

Hi-Z*

Stand-by (idling)

b

H

L

VCC

H

L

Forward (OUT1 > OUT2)

c

L

H

VCC

L

H

Reverse (OUT1 < OUT2)

d

H

H

X

L

L

Brake (stop)

e

PWM

L

VCC

H

PWM

__________

Forward (PWM control mode A)

f

L

PWM

VCC

PWM

__________

H

Reverse (PWM control mode A)

g

H

PWM

VCC

PWM

__________

L

Forward (PWM control mode B)

h

PWM

H

VCC

L

PWM

__________

Reverse (PWM control mode B)

i

H

L

Option

H

PWM

__________

Forward (VREF control)

j

L

H

Option

PWM

__________

H

Reverse (VREF control)

* Hi-Z is the off state of all output transistors. Please note that this is the state of the connected diodes,

which differs from that of the mechanical relay.

X : Don’t care

a) Stand-by mode

Stand-by operates independently of the VREF pin voltage. In stand-by mode, all internal circuits are turned off,

including the output power transistors. Motor output goes to high impedance. If the motor is running at the switch to

stand-by mode, the system enters an idling state because of the body diodes. However, when the system switches

to stand-by from any other mode (except the brake mode), the control logic remains in the high state for at least 50µs

before shutting down all circuits.

b) Forward mode

This operating mode is defined as the forward rotation of the motor when the OUT1 pin is high and OUT2 pin is low.

When the motor is connected between the OUT1 and OUT2 pins, the current flows from OUT1 to OUT2. For

operation in this mode, connect the VREF pin with VCC pin.

c) Reverse mode

This operating mode is defined as the reverse rotation of the motor when the OUT1 pin is low and OUT2 pin is high.

When the motor is connected between the OUT1 and OUT2 pins, the current flows from OUT2 to OUT1. For

operation in this mode, connect the VREF pin with VCC pin.

d) Brake mode

This operating mode is used to quickly stop the motor (short circuit brake). It differs from the stand-by mode because

the internal control circuit is operating in the brake mode. Please switch to the stand-by mode (rather than the brake

mode) to save power and reduce consumption.

a) Stand-by mode

b) Forward mode

c) Reverse mode

d) Brake mode

Fig.35 Four basic operations (output stage)

M

ON

OFF

OFF

ON

M

OFF

ON

ON

OFF

M

OFF

ON

OFF

ON

OFF

OFF

OFF

OFF

M