FAN8461G Fairchild Semiconductor, FAN8461G Datasheet - Page 9

• Manufacturer Part Number: FAN8461G
• Description: Motion Motor Control, Single Phase Full Wave BLDC Motor Driver
• Manufacturer: Fairchild Semiconductor

3. Hall Sensor Amplifier
The hall current (I
Where, RH is an external limiting resistor and Ri is input impedance of hall sensor. An external capacitor, C
reduce a power supply noise.C
amplifier is between 0V and V
Table 1. Hall Sensor Outputs and Related Pin outputs
8. Open Collector FG Output for Speed Feedback
The FG output comes from the hall amplifier output. Because the FG output is open collector type, end user can pull up this
pin with a external resistor to the supply voltage of their choice(that is 5 or 3.3V). This resulting output signal has two pulses
per revolution on a four pole motor. It is recommednd that this FG output be higher than the GND potential.
9. Supply Voltage Consideration
A supply sustain capacitor(C
diode(D
VCC pin voltage. This capacitor absorbs motor recirculating current and limits VCC pin voltage. In general, large motor wind-
ing induactance and current need large value of C
10. Thermal Shutdown
TSD on: Two high side outputs are off.(Typ. 175° C)
TSD off:The circuit can be reactivated and begin to operate in a normal condition. (Typ. 150° C)
I
H
H+
H
L
=
-------------------------- -
(
R
R
-
) prevent motor current from recirculating to power source when phase commutation occur. This results in increasing
V CC
H
H-
+
H
L
R
V S - 2 .8 V
i
)
H
) is determined as follows;
V S / 2
Low Level
Low Level
G N D
V S
LD
-
R)
H2
CC
should be placed as close to VCC pin with GND as layout permits. A reverse supply protection
-2.8V as shown in following figure.
can reduce the instant peak current using H-bridge’s commutation. The input range of hall
OUT 1
H
L
-
Figure 3. Hall Amplifier Input Range
Figure 2. Hall Sensor Interface
FAN8461G
R.
OUT 2
H
L
-
2
1
C
H2
IN+
IN-
AL
H
L
L
V+
RH
Ri
Sensor
Hall
C
H1
TACO
L or H
H
L
ROTATING
Remark
LOCK
H1
, can be used to
FAN8461G
9