LV8161MU Datasheet, PDF (8/11 Pages) ON Semiconductor – Single-Phase Fan Motor Driver

Application Circuit Example
LV8161MU
*5
1 [IN1]
[COUT] 10
H
2 [HB]
[CIN] 9
*1
3 [IN2]
[FG] 8
(
)
FG_OUT
*2
4 [OUT1]
[VCC] 7
()
5 [GND]
[OUT2] 6
*3
M
*1. The hall signal must be wired as short as possible for avoiding the noise.
If in influence of the noise, insert the capacitor between IN1 and IN2.
*2. It is recommendation that the resistance of 1kΩ or more is connected to FG pin to the series
when GND-open or mis-connecting.
*3. The power-supply voltage might rise by the influence of the coil kickback etc. when using the
diode for preventing the destruction at reverse-connected. In that case, insert the zener diode
between the power supply and GND, and suppress the rise of the voltage of VCC pin.
*4. It is necessary to wire the VCC and the GND line as wide and short as possible.
*5. The reference clock that decides the rotational speed is generated with the connection of C1 pin,
COUT pin, R1, and C1 as shown in figure. The relation among rotational speed N [rpm] of
the motor with m-poles and the cycle of the reference clock T [s] is as follows.
N _×m₌ 1
60 2 1000 × T
Otherwise, the relation among T[s], C1 [F], and R1 [Ω] is as follows in consideration of 150 [Ω]
built into COUT terminal.
T = 1.09862 × C₁ × (R₁ + 150)
Therefore, the relation among rotational speed N [rpm] of the motor with m-poles, C1 [F], and
R1 [Ω] is led from above formula as follows.
N
60
×
m
2
=
910.2328E − 6
C₁ × (R₁ + 150)
For example, when setting to rotate the motor with 4-poles at 2,700 [rpm] as C1=1,000 [pF],
2700
60
×
4
2
=
910.2328E − 6
1000E −12 × (R₁ + 150)
⇔
R₁
=
910232.8
90
− 150
=
9.964[kΩ]
Actually, the error margin of rotational speed is caused by the operation time of the circuit, the
influence of parasitic elements on the circuit board, etc. Therefore, the value of C1 and R1 should
be decided by confirming with the operation with the actual motor.
When the value of C1 or R1 changes by the thermal condition or the manufacturing tolerance etc,
the rotational speed of the motor changes. So, it is necessary to use the capacitor and the resistor
with better characteristics when high accuracy at rotational speed is needed.
No.A2311-8/11