Datasheet

 2002-2013 Microchip Technology Inc. DS21755C-page 17
TC646B/TC648B/TC649B
FIGURE 4-10: TC648B Behavioral Algorithm.
V
AS
= 0V
V
IN
< V
AS
?
Auto-
Shutdown
V
OUT
= 0
Yes
No
No
Yes
Power-Up
Power-on
Reset
OTF
= 1
V
IN
>
(V
AS
+ V
HAS
)
Yes
No
Fire Start-up
Timer
(1 sec)
V
IN
> 1.20V
V
OUT
Proportional
to V
IN
V
IN
> V
OTF
?
Auto
Shutdown
V
OUT
= 0
No
No
Yes
Normal
Operation
V
OUT
= 0
No
Yes
Yes
Minimum
Speed Mode
Normal
Operation
OTF = 1OTF = 0
V
IN
< V
AS
?
Minimum
Speed Mode
V
IN
= 0V
Power-Up
V
IN
> 1.20V
V
OUT
Proportional
to V
IN
V
IN
> V
OTF
?
No
Yes
OTF = 1OTF = 0
V
OUT
= 0
Yes
No
No
Yes