KA3903 FAIRCHILD [Fairchild Semiconductor], KA3903 Datasheet - Page 6

• Manufacturer Part Number: KA3903
• Description: Power Window Motor Control IC
• Manufacturer: FAIRCHILD [Fairchild Semiconductor]

Start Stage
In the state of the start-key turned off, all the blocks in the FAN8903 are kept to be off because the power is not supplied into
UVLO&REFERENCE block.
When the start-key is turned on, the power is supplied into UVLO block to activate reference block in normal condition.
Step and Auto Time
If the up/down switch is pushed less than a set time (T
until Vct equals to V5. At that time TR (Q1) is turned on and stops the operation.
But if longer than T
terminates its operation.
The T
In the manual mode, the window goes up or down just while a switch is pushed. In the step mode and the auto mode, even after
releasing the switch, the window continues its movements except for pushing the switch again (the topple) or happening to the
stall condition.
6
S
T
T
and Ta(auto time) were determinate by components (Rt & Ct), external divider and Vref3.
a
S
=
=
2.10
0.05
S
BAT.
Rt Ct
, capacitor (Ct) continues its charge until Vct equals to Vref3. Then Q1 is turned on and the auto function
Rt Ct
,
,
START KEY
where Vref3 = 4.4V
where V5 = 0.25V
R6
R5
V5
R1
300k
R2
10k
Vct
Ct
Rt
+
V1
C1
47 F
s
+
), TR (Q1) will be turned off and capacitor (Ct) is charged exponentially
15
FAN8903
2
3
4
0.92V
(at V
FAN8903
CC
Vref3
Q1
+
=12V)
COMP1
+
+
V
CC
UVLO &
REFERENCE
V
CC
FAN8903(KA3903)