MB3873

13

s SETTING THE SOFT START TIME

When the MB3873 is started, the soft start capacitor (Cs) connected to the CS terminal begins charging. While

the CS terminal voltage is := 0 to 1.1V, the oscillator frequency is controlled by the CS terminal voltage, thereby

controlling the output voltage.

The soft start capacitor charging current is as follows

ICS1 := 25

µA (CS pin voltage := 0 to 1.1V)

ICS2 := 2.5

µA (CS pin voltage := 1.1 to 3.1V (CS pin clamp voltage))

Soft start time (time until CS pin voltage reaches 1.1V)

s SETTNG THE OVERLOAD DETECTION DELAY TIME

( := 10

µA), increasing the CD terminal voltage.

When the CD terminal voltage exceeds the threshold voltage ( := 4V), the error detection latch is set, and the

VREF terminal (pin 10) and OUT terminal (pin 8) are set to “L” level.

Overload detection delay time (time from overload detection until error latch is set)

1.2

25 [

µA]

3.9

10 [

µA]