MLP2012S datasheet(11/50 Pages) SII

11 / 50 page

STEP-UP, SUPER-SMALL PACKAGE, 1.2 MHz PWM/PFM SWITCHABLE SWITCHING REGULATOR

Rev.2.0_01

S-8363 Series

3. Soft-start function

The S-8363 Series has the built-in soft-start circuit. When power-on (connecting

OFF

to VIN) or after

start-up at

OFF

= “H”, the output voltage (VOUT) gradually rises, suppressing rush current and overshoot of

the output voltage. In the S-8363 Series, the soft-start time (tss) is from start-up to the time to reach 90% of the

VOUT output voltage setting value (VOUT(S)). A reference voltage adjustment method is adopted as the soft-start

method, the reference voltage gradually rises from 0 V simultaneously with start of the soft-start. The soft-start

circuit has two operation modes which is selected according to the VOUT voltage at start-up.

3.1 VOUT voltage at start-up

> STU release voltage

The soft-start starts when the reference voltage gradually rises after

OFF

= “H”.

Reference voltage

from

error amplifier

Soft-start time (tss)

Time [s]

0 V

VOUT

× 0.90

0 V

Output voltage

(VOUT)

Input voltage

(VIN)

Soft-start period

ON/OFF

voltage

STU release

0 V

Figure 10

MLP2012S Datasheet(PDF) 11 Page - Seiko Instruments Inc