TC646 Microchip, TC646 Datasheet - Page 9

• Manufacturer Part Number: TC646
• Description: PWM Fan Speed Controller
• Manufacturer: Microchip

FIGURE 4-1:
2002 Microchip Technology Inc.
Hot Start
No
Auto-Shutdown
FAULT = 1
V
V
IN
OUT
V
> V
IN
FAULT = 1
V
Fire Start-up
Power-Up
Fan Pulse
Detected?
Power-on
Yes
Operation
IN
Yes
No
No
< V
Reset
= 0
(1 SEC)
Normal
REL
Timer
< V
SHDN
?
AS
?
?
Yes
No
No
Yes
TC646 Behavioral Algorithm Flowchart.
Yes
V
IN
V
> (V
FAULT = 0,
IN
Yes
Fan Fault
Shutdown
V OUT = 0
V
Power-Up
Shutdown
Fire Start-up
V
OUT
< V
Detected?
Fan Fault
Auto-
Fan Pulse
OUT
(1 SEC)
No
AS
Timer
SHDN
= 0
Yes
+ V
YES
= 0
(V
HAS
?
AS
)?
V
+ V
IN
No
V
>
Yes
Yes
HAS
IN
> V
)
No
REL
?
Cycling
Power
No
Yes
No
Yes
V IN < V
Pulse Detector
V
Clear Missing
V
Proportional
Fan Pulse
Detected?
No
Operation
No
IN
IN
No
Normal
to V
V
> V
< V
OUT
SHDN
IN
No
OTF
AS
?
?
?
Expired?
Yes
No
M.P.D.
FAULT = 0
Yes
Yes
(100msec)
Fan Pulse
Detected?
Diagnostic
Shutdown
V
OUT
Timer
Auto
Fire
Yes
Yes
= 0
(V
AS
No
V
Shutdown
V
Yes
+ V
IN
OUT
>
Yes
HAS
= 0
Fire Start-up
)
Detected?
Fan Pulse
Fan Fault
No
(1 sec)
Timer
DS21446C-page 9
TC646
Hot Start
No
Power-Up
V
IN
> V
Yes
REL
No