AMC8500 Datasheet, PDF (19/27 Pages) List of Unclassifed Manufacturers – TWO PHASE VARIABLE SPEED FAN MOTOR CONTROLLER

Preliminary Specification
aMC8500
Figure 35- Simistor™ Sensing Variable Speed Temperature Regulator
12 V
5
R4
H
aSM121
7
R1
R3
R2 ⁸
9
R6
R5
6
H
10
Reference
Op Amp
Oscillator
R
12
3
4
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
Closest Standard 1.0% Resistor Values
Gain
Offset
Min Speed
R1
R2
R3
R4
R5
R6
Ω
13700
10500
1070
1070
13000
Ω
16500
76800
8870
48700
169000
Ω
1400
1370
232
1330
2320
Ω
5360
6810
845
4120
7320
Ω
1070
1070
-
1070
953
Ω
1130
1130
-
1270
1130
This application circuit uses a Simistotr™ solid state silicon temperature sensor that provides a precision signal of 10 mV/°C with an
offset of 500 mV at 0°C. The Op Amp in conjunction with the Reference is used to gain-up and offset the signal before applying it to the
speed control input. The above table shows five application requirements that are similar to those in Figure 33 with the calculated
resistor values. The Simistor™ sensor allows a reduced component count when compared to the equivalent thermistor circuit. In each
example, the required PWM %on or motor speed is defined for a minimum and maximum sensor temperature, and for 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
- 19 -
www.andigilog.com
August 2006 - 70A04018