Technical Note
6/11
BA6247FP-Y,BA6238A
www.rohm.com
2011.05 - Rev.B
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●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
These are the resistors and zener diode used when output high voltage is set. Zener diode ZD is recommended to be
used instead of resistor R3 when the power supply voltage is unstable.
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, C4, C5
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
Table 3 Logic table, BA6247FP-Y / BA6238A
IN1 IN2 IN3 OUT1 OUT2 OUT3 OPERATION
L L
L
L L L Brake (stop)
H
H L
L H L OPEN* Motor 1, forward (OUT1 > OUT2)
H L H OPEN* Motor 1, reverse (OUT2 > OUT1)
L H
L H OPEN* L Motor 2, forward (OUT1 > OUT3)
H L OPEN* H Motor 2, reverse (OUT3 > OUT1)
H H
L
L L L Brake (stop)
H
* 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.
