AT1380A

Preliminary Product Information

Switching Regulator Controller for LCD Bias

2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.

Tel: 886-3-563-0878

Fax: 886-3-563-0879

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Functional Description

Soft Start SCP

Figure 1. Soft-Start SCP circuit

At power-on, the AT1380A enters the soft-start mode to prevent current spike and overshoot. The

capacitor CS is charged from 0V at a constant current of 1

µA.

The soft-start time for the duty cycle

the SCP function. If the output load conditions change rapidly causing the output to drop suddenly, the

When the external capacitor is charged above 0.8V, the output pin is set low. Once the latch circuit has

set, the capacitor CS will be discharged to low state and the latch circuit will not reset until power is

turned off or the power supply is restarted.

Short-circuit detection time (or full soft-start time) :

)

(

8

.

0

F

CS

t

PE

µ

×

=

)

(

8

.

0

F

CS

t

S

µ

×

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