Technical Note

11/15

BA6956AN, BA6287F, BA6285FS, BA6285AFP-Y, BA6920FP-Y

www.rohm.com

2009.04 - Rev.A

○

c

2009 ROHM Co., Ltd. All rights reserved.



External application components

1) Resistor for the current limitation, R1

This is a current limiting resistor for collector loss reduction and at the time of short-circuited output. It depends on the

power supply voltage used, etc., but choose resistance of about 5 to 10Ω. In addition, set resistance with utmost care

to voltage drop caused by inrush current that flows when the motor is started.

2) Resistors and zener diode for the output high voltage setting, R2, R3 and ZD

0.75V) Zener diode ZD is recommended to be used instead of resistor R3 when the power supply voltage is unstable

for BA6956AN and BA6920FP-Y.

3) Stabilization capacitor for the power supply line, C1

Please connect the capacitor of 1μF to 100μF for the stabilization of the power supply line, and confirm the motor

operation.

4) Phase compensating capacitor, C2, C3

Noise is generated in output pins or oscillation results in accord with the set mounting state such as power supply

circuit, motor characteristics, PCB pattern artwork, etc. As noise oscillation measures, connect 0.01μF to 0.1μF

capacitors.



Functional descriptions

1) Operation modes

a) Stand-by mode

In stand-by mode, all output power transistors are turned off, and the motor output goes to high impedance.

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.

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.

d) Brake mode

This operating mode is used to quickly stop the motor (short circuit brake).

Note) Switching of rotating direction (FWD/REV)

When the rotating direction is changed over by the motor rotating condition, switch the direction after the motor is

temporarily brought to the BRAKE condition or OPEN condition. It is recommended to keep the relevant conditions

as follows:

via OPEN: The time longer than 1 ms is recommended.

Table 6 Logic table

IN1

IN2

OUT1

OUT2

Operation

L

L

OPEN*

OPEN*

Stop (idling)

H

L

H

L

Forward (OUT1 > OUT2)

L

H

L

H

Reverse (OUT1 < OUT2)

H

H

L

L

Brake (stop)

* OPEN 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.

** Output OUT1 and OUT2 become OPEN regardless of the input logic of FIN and RIN when switching to the power save mode with the POWERSAVE pin.