bh6799fvm ROHM Co. Ltd., bh6799fvm Datasheet - Page 10

• Manufacturer Part Number: bh6799fvm
• Description: Dc Brushless Motor Driver Series For Cooling Fans Low-voltage Single-phase Full-wave Dc Brushless Fan Motor Drivers
• Manufacturer: ROHM Co. Ltd.

2) Soft switching (silent drive setting)
3) Hall input setting
＜BH6799FVM、BH6789FVM、BH6766FVM＞
〇Reducing the noise of hall signal
Input signal to hall amplifier is amplified to produce an output signal.
When the hall element output signal is small, the gradient of switching of output waveform is gentle; When it is large,
the gradient of switching of output waveform is steep. Gain of 300 times (typ.) is provided between input and output.
Enter an appropriate hall element output to IC where output waveform swings sufficiently.
Hall input voltage range is shown in operating conditions.
Adjust the value of hall element bias resistor R1 in Fig.29 so that the input voltage of a hall amplifier is input in "hall
input voltage range" including signal amplitude.
Hall element may be affected by Vcc noise depending on the wiring pattern of board. In this case, place a capacitor like
C1 in Fig.29. In addition, when wiring from the hall element output to IC hall input is long, noise may be loaded on
wiring. In this case, place a capacitor like C2 in Fig.29.
H-
C2
RH
R1
(H+)-(H-)
H+
OUT1
Fig.27 Relation between hall element output amplitude and output waveform
C1
Hall bias current
＝ HB / (R1 + RH)
HB
Fig.29 Application near of hall signal
Fig.28 Hall input voltage range
10/16
Hall element
H-
＜BD6989FVM＞
C2
RH
R1
Vcc
Hall input voltage range upper limit
Hall input voltage range lower limit
GND
H+
C1
Hall bias current
＝ Vcc / (R1 + RH)
Vcc