TC652 Fan Control Demo Board User’s Guide
DS21506B-page 10 2002 Microchip Technology Inc.
FIGURE A-2: TC652 Demo Board Functional Block Diagram
A.3 DEMO BOARD COMPONENTS
Table A-1 lists the various components and values associated with the TC652
demonstration board.
TABLE A-1: FAN CONTROL DEMO BOARD COMPONENTS AND VALUES
PWM
SENSE
R
1
1 kΩ
Test Point
(TP
1
)
V
DD
V
DD
1
3
4
5
7
8
SHDN
Shutdown
Input
T
OVER
TC652/TC653
U1
Q
1
Si2302
GND
2
FAULT
Fan
Fault
LED
(Red)
JP
1
GND
6
C
2
0.01 µF
R
3
4.7
Ω
(Default)
C
1
1 µF
V
FAN
T
OVER
LED
(Green)
R
2
1 kΩ
D
2
D
1
User
selectable
+
+
–
Component Typical Value Comments
C
1
1 µF, 1206 chip capacitor Power supply filter.
C
2
0.01 µF, 1206 chip capacitor SENSE input coupling capacitor.
D
1
4.5 mA miniature red LED D
1
lights when FAULT output is LOW (active).
D
2
4.5 mA miniature green LED D
2
lights when T
OVER
output is LOW (active).
Q1 Logic Level MOSFET Transistor output option. A logic level MOSFET (Si2302) is used
on the TC652 to accommodate various types of fans. The output
drive device can also be an NPN transistor, depending on cost
constraints and fan current.
R
1
1 kΩ, 1206 chip resistor D
1
(red LED) current limiting resistor.
R
2
1 kΩ, 1206 chip resistor D
2
(green LED) current limiting resistor.
R
3
4.7Ω leaded resistor Fan current sensing resistor. Value depends on full speed fan
current. Typical values appear in Table 2-1.
U
1
TC652AEVUA;
low temperature limit: T
L
25°C,
high temperature limit: T
H
45°C
TC652 or TC653 fan control IC.
