M51971FP Mitsubishi, M51971FP Datasheet - Page 6

• Manufacturer Part Number: M51971FP
• Description: MOTOR SPEED CONTROL
• Manufacturer: Mitsubishi

Upper side : Motor speed (FV conversion waveform of tacho-
Lower side : Supply voltage
Horizontal axis : 20 ms/div
Time constant of motor
Application Characteristics Example
100
0%
90
10
0
4
3
2
1
Output voltage range at pin
voltage characteristics
generator frequency)
4
T
a
= 75 C
Supply voltage V
100 ms
T
8
a
= 25 C
12
T
a
CC
= -20 C
(V)
9
16
– Supply
How to determine R and C
These constants determine the motor rotating speed. If the motor
rotating speed and the number of poles of tacho-generator are
assumed to be N and P, respectively, the following relational
expression is generally established. According to the required
rotating speed, select the constant in such a way that R can be
put in the range of 10k
take care for leak current that may flow on the surface of the
printed circuit board.
10000
7000
5000
3000
2000
1000
Tacho-generator output frequency –
Connection resistance characteristics at pin
700
500
300
200
160
120
–40
MITSUBISHI <CONTROL / DRIVER IC>
80
40
0
10
Connection resistance R (k ) at pin
0
NP
Buffer amplifier offset voltage –
Voltage characteristics at pin
20 30
1.20 • R • C
1
Voltage at pin
– 500k . When using a high resistance,
MOTOR SPEED CONTROL
50 70 100
1
2
M51971L/FP
8
200 300 500
V
8
V
(V)
3
CC
=9V
1
R (k )
8
1000
4
1