NJU7347 New Japan Radio Co.,Ltd, NJU7347 Datasheet - Page 7

• Manufacturer Part Number: NJU7347
• Description: Nju7347 Single-phase Dc Brushless Motor Driver Ic
• Manufacturer: New Japan Radio Co.,Ltd

3. Design of hall element bias resistance (R1 and R2)
Where C2 is 0.47uF:
constant start up must be confirmed in actual evaluation taking operating variations (i.e.Temperature, Voltage change
and so on) in consideration.
A typical value of C2 is either 0.47uF or 1uF depending on a motor.
Non-excitation hall bias voltage is to be set at a half of V
Therefore the same value of hall bias resistors is selected for R1 and R2.
Auto Resume Time (Toff) is given by:
Where C2 is 0.47uF:
In actual application, Lock detection time (Ton) is affected by the mechanical time constant of a motor. Therefore,
The common-mode input voltage is between 0.2V and V
Given that the bias current is set to be 5mA by HW101A datasheet, R1 and R2 can be determined as follows:
Hall amplifier is a differential amplifier.
R
R
1
1
T
T
T
ON
OFF
OFF
OUTB
OUTA
R
R
IN+
CT
FG
IN-
2
2
. 0
C
0
Rin
1
47
2
k
47
V
CL
10
I
DCHG
10
Ihbias
V
6
V
DD
ID
6
3
Lock
2
sec
0
2
2 .
3 .
.32
6 .
5
12
0
10
10
VCL
6 .
10
0
.6
6
3
6
Toff
Lock Protection Operating Time
0
2
.25
4 .
2
.5
k
sec
sec
Ton
VID
DD
for effective use of common-mode input voltage range.
DD
-4V and the input signal must be within the range.
Toff
LD Release
NJU7347
Preliminary
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