BD6220_09 Datasheet, PDF (10/17 Pages) Rohm – H-bridge drivers (18V max.)

BD6220, BD6221, BD6222, BD6225, BD6226, BD6227
Technical Note
e) f) PWM control mode A
The rotational speed of the motor can be controlled by the switching duty when the PWM signal is input to the FIN
pin or the RIN pin. In this mode, the high side output is fixed and the low side output does the switching,
corresponding to the input signal. The switching operates by the output state toggling between "L" and "Hi-Z".
The PWM frequency can be input in the range between 20kHz and 100kHz. Note that control may not be attained
by switching on duty at frequencies lower than 20kHz, since the operation functions via the stand-by mode. Also,
circuit operation may not respond correctly when the input signal is higher than 100kHz. To operate in this mode,
connect the VREF pin with VCC pin. In addition, establish a current path for the recovery current from the motor, by
connecting a bypass capacitor (10µF or more is recommended) between VCC and ground.
ON
OFF
M
OFF
ON
ON
OFF
M
OFF
OFF
Control input : H
Control input : L
Fig.38 PWM control mode A operation (output stage)
FIN
RIN
OUT1
OUT2
Fig.39 PWM control mode A operation (timing chart)
g) h) PWM control mode B
The rotational speed of the motor can be controlled by the switching duty when the PWM signal is input to the FIN
pin or the RIN pin. In this mode, the low side output is fixed and the high side output does the switching,
corresponding to the input signal. The switching operates by the output state toggling between "L" and "H".
The PWM frequency can be input in the range between 20kHz and 100kHz. Also, circuit operation may not respond
correctly when the input signal is higher than 100kHz. To operate in this mode, connect the VREF pin with VCC pin.
In addition, establish a current path for the recovery current from the motor, by connecting a bypass capacitor (10µF
or more is recommended) between VCC and ground.
OFF
OFF
M
ON
ON
ON
OFF
M
OFF
ON
Control input : H
Control input : L
Fig.40 PWM control mode B operation (output stage)
FIN
RIN
OUT1
OUT2
Fig.41 PWM control mode B operation (timing chart)
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10/16
2009.08 - Rev.C