TC642 Microchip, TC642 Datasheet - Page 8

• Manufacturer Part Number: TC642
• Description: PWM Fan Speed Controller
• Manufacturer: Microchip

TC642
FIGURE 4-1:
DS21444C-page 8
V
Fire Start-up
FAULT = 1
MIN
Detected?
Power-Up
Power-on
No
Fan Fault
Operation
(1 SEC)
No
Reset
Normal
Timer
< V
SHDN
Yes
V
FAULT = 0,
V
Yes
V
MIN
Yes
Yes
Fan Fault
Yes
MIN
Power-up
OUT
< V
> V
TC642 Behavioral Algorithm Flowchart.
= 0
Fire Start-up
SHDN
REL
Shutdown
V
Fan Pulse
Detected?
Fan Fault
OUT
(1 SEC)
No
Timer
?
?
YES
= 0
No
No
V
MIN
Yes
> V
Cycling
Power?
REL
?
Yes
No
No
Yes
Proportional to Greater
V
of V
V
Missing Pulse
MIN
Detected?
IN
Fan Pulse
Operaton
No
No
Normal
Detector
IN
> V
V
Clear
< V
OUT
or V
OTF
No
SHDN
MIN
?
?
Expired?
No
M.P.D.
Yes
Yes
FAULT = 0
Fire Diagnostic
Detected?
Fan Pulse
(100msec)
Timer
Yes
Yes
2002 Microchip Technology Inc.
No
Yes
Shutdown
V
OUT
Detected?
Fan Pulse
Fan Fault
= 0
Fire Start-up
(1 SEC)
Timer
No
V
MIN
Power-up
> V
Yes
REL
No