UTC 1470
LINEAR INTEGRATED CIRCUIT
Em
M
R
T
i2
2
1
1470
3
4
R
S
BASIC EQUATION FOR MOTOR
Vref
)
E
t
= Vref + R
T
(
i
2
+
Rs
Vcc
1
i
2
=
i
4
+
i
q
K
Vref
i
4
=
i
m
+
Rs
1
Vref
E
t
= Vref + R
T
(
i
4
+
i
q + Rs )
K
1
Vref
Vref )
(
i
m
+
+
i
q +
E
t
= Vref + R
T
{
}
Rs
Rs
K
1
R
T
R
T
( 1+ ) } + R
T
i
q
+
E
t
= Vref { 1 +
i
m
Rs
K
K
︷
i
m
i
4
They also give : Em = Eo + R
m
i
m
1
R
T
} + R
T
i
q
( 1+
Eo = Vref {1 +
K
Rs
Rm = R
T
K
︷
E
t
Eo : Back Electromotive Force
Rm: internal Resistance(of the Motor)
K : Reflection Confficient = (
i
4 /
i
2 )
﹙
APPLICATION CIRCUIT
Vcc
L (47μH)
R
T
R
S
1
2
4
M
Motor
Vcc = 12V
R
m
= 19.5Ω
R
T
= 330Ω
Rs = 1kΩ
Eo = 2.3V
K = 20
Vref
COMPARATOR
STARTING
CIRCUIT
3
CURRENT
MILLOR
Note 1.The motor speed can be adjusted by the varisble resistor
Rs
min.
=
Vref
*
R
T
Eo - Vref- Iq
*
R
T
R
S
.
Note 2. If R
Tmax.
> k
*
Rm min,instabilicy of the motor may occur.
UTC
UNISONIC TECHNOLOGIES CO. LTD
4
QW-R109-007,B
UTC-IC [ UNISONIC TECHNOLOGIES ]
