AMC8500 Datasheet, PDF (18/27 Pages) List of Unclassifed Manufacturers – TWO PHASE VARIABLE SPEED FAN MOTOR CONTROLLER

Preliminary Specification
aMC8500
Figure 34- Thermistor Sensing Variable Speed Temperature Regulator
12 V
12
3
4
R2 R6
5
H
7
R1
T
R3
10 k _R5
@ 25°C
β = 3694
R8
R4 ⁸
9
R7
6
H
10
Reference
Op Amp
Oscillator
R
Under Voltage
Lockout
Hall Amplifier
Non-Overlap
Commutation
Fault Timer
Power Down
Kick Start
Min Speed
Comp
PWM Comp
PWM
Logic
Digital
Detector
H
SN
M
N
S
16
1
Motor
Drives
Thermal
Shutdown
Current
Limit
Latch
R
Q
S
10 μA
Current Limit
Comp
15
13
2
10 nF
11
14
T_min
Speed
°C
30
30
35
37
40
Application Requirements
PWM
T_max
Speed
PWM
Minimum
Speed
Setting
%on
°C
%on
%on
35
40
100
35
67
38
100
35
30
50
100
0
30
40
100
30
30
50
100
30
Thermistor
R1
Ω
10000
10000
10000
10000
10000
Closest Standard 1.0% Resistor Values
Linearization
Gain
Offset
R2
R3
R4
R5 R6
Ω
6650
6980
4990
5900
4640
Ω
11500
11500
15400
10200
14700
Ω
32400
16200
29100
133000
49900
Ω
1130
1870
1370
1000
1000
Ω
1150
1330
1300
1000
1000
Min Speed
R7 R8
Ω
2550
2550
-
2910
2910
Ω
1330
1330
-
1330
1330
The Op Amp used in conjunction with the Reference is extremely useful in providing voltage gain and offset to condition the thermistor
signal so that it can drive the Speed Control Input. The table shows five different application requirements with the calculated closest
standard 1.0% resistor values. In each example, the required motor speed or PWM %on is defined for two sensor temperatures along
with a minimum speed setting. In the third application, the minimum speed set input is not required and the comparator must be disabled
by connecting Pin 6 to Pin 14. Note that the total Reference load current must exceed 2.0 mA in order to disable the automatic power
down feature.
© Andigilog, Inc. 2006
- 18 -
www.andigilog.com
August 2006 - 70A04018