FAN8903(KA3903)

10

The position of the sensor must be set adequately upper part of the window. When the obstacle between the window glass and

the upper limit are inserted, the light sensor TR is turned off. The sensor have a two function;

- End position switch,

- Issuing the OCP signal.

Q2 is used to make the F/C pin low, and Q4 enables to turn-on Q6 to issue the OCP signal.

As soon as Q2 is turned on, V2 changes from the equation mentioned in 6.2 paragraph to the below equation.

and OP-amp output become low level. Therefore the HBP logic stops the motor and reverses the direction of the motor.

You can adjust the delay time by changing the value of the resistor, R10. The added part works only when Q5 is on-state. In

other words, when the window glass is moving upward, the added part operates. Q3 is also turned on and holds the F/C pin low

level.

Output Stage

The output stage is a darlington TR with an integrated zener diode, and designed at a pulse current of a approx. 0.4A. The

zener diode limits the inductive switch-off voltage. The relay coil has a typical resistances of 200

Ω, and the zener diode volt-

age is 18.6V.

With the circuitry of this type, the FAN8903 can sustain 24V for one minute (or continuously) and load dump

(70V, 0.2sec) condition without a damage.

V2

Vcom

R10 // Rntc

Rt

+

()

[] R10 // Rntc Rt

+

() R5

+

[]

⁄

×

=

+

−

+

−

+

−

Start key

Light

sense

Added part

KSR1012

R4

V1

Q2

Q3

Motor

KSR2007

Q4

KSC945

Pin #8

NTC

Rt

(+)

C3

COMP

OP-amp

Vro

0.8V

OCP

Vref

Q6

R10

R3

Q5

FAN8903

5

2

6

7

C2