an6657s Panasonic Corporation of North America, an6657s Datasheet - Page 6

• Manufacturer Part Number: an6657s
• Description: Micromotor Forward/ Reverse Electronic Governors
• Manufacturer: Panasonic Corporation of North America

AN6657, AN6657S
• Temperature Compensation of Motor Speed
compensation of the motor speed can be done by using 3,900
r.p.m/˚C metal coated or coiled resistor as the torque control
resistance r
temperature coefficient of about 2,000r.p.m/˚C as the speed
control resistance r
Fig. 3.
For the normally used motor with core, the temperature
Characteristics Curve
800
600
400
200
0
0
r
ture Characteristics
1
Temperature Characteristics = Ra Tempera-
1
, and metal coated resistor with a positive
AN6657S
4
.
40
Ambient Temperature Ta (˚C)
T
AN6657
M
(Torque)
P
D
– Ta
80
All Temperatures
120
160
the torque control resistance r
and controls the input voltage of the amplifier in the IC to
limit the current.
Limiting the current can reduce the useless current at start
and motor lock time and prevent the supply voltage from
dropping.
The limited current I
expression.
V
When r
• Current Limiting Function
Lim
The current limitting function detects the voltage drop of
4000
2000
: V
I
I
0
Lim
Lim
0
1
BEON
= 1.2 , from the expression (8) I
=
=
Constant
Speed
Voltage < 0.6V
0.6V
V
1.2
r
Lim
1
FF/REW
40
= 500mA
V
CC
r.p.m. Load Torque
Lim
= 6V
Load Torque T (g – cm)
is calculated by the following
1
, operates the PNP transistor,
80
V
Lim
CC
ICs for Motor
= 9V
120
is ;
160
(8)