KA3903 FAIRCHILD [Fairchild Semiconductor], KA3903 Datasheet - Page 9

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

FAN8903(KA3903)
Human Body Protection(HBP)
Using An End Switch
The human body protection is to be carried out when the over current protection signal is issued just while the
is up going and the end switch is closed, in the auto mode. The controller stop the window glass, and then reverses the rotating
direction of motor to move down the window at the bottom.
There are some cases in the window glass to be locked; its upper limit, bottom, and obstacle like human body, neck, and hand
etc. The OCP function would work in any cases. So it is necessary for the controller to discriminate whether something is
squeezed between the window glass and the window frame or not.
The end switch is opened only when the window glass reaches almost its upper limit.
Leave the F/C pin open unless you want this function.
Using Photo Devices (No Touch Sensor)
In case of using an end switch, the HBP function works on the condition that the over current signal is issued.
So it could have some sensitivity problem. It is very hard to decide what the optimal reference current and cancel time are.
We have tested new principle and as a result, developed one light based HBP function. The below figure explain the principle
of the operation.
As sender and receiver are arranged together, it is possible for the receiver to detect the sent diode light.
10m
R
Vrs
S
MOTOR
R3
47k
260k
Rt
NTC
V2
C2
105
WINDOW
FRAME
switch
End
2
6
7
FAN8903
Vref
OP-amp
+
R4
10K
C3
103
V1
0.8V
Vro
+
5
FAN8903
Vref
OCP
+
COMP
A
V
CC
Motor current
Stall current
Vcom
window glass
Vref
C
9