RP116Z

NO.EA-281-131031

7

CONSTANT SLOPE CIRCUITS

The RP116Z Series is equipped with a constant slope circuit as a soft-start circuit, which allows the output

voltage to start up gradually when the CE is turned on.

The constant slope circuit minimizes the inrush current at the start-up and also prevents the overshoot of the

output voltage.

The capacitor to create the start-up slope is built in the IC that does not require any external components. The

start-up time and the start-up slope angle are fixed inside the IC. For more details, please refer to the graph 15 of

“Inrush Current Characteristics Example”.

Inrush Current Characteristics Example (C1=1.0

μF, Topt=25ºC)

RP116Z071B/D

RP116Z121B/D

40

80

120

160

20

0

60

100

140

180

2.00

1.75

1.50

1.25

1.00

0.75

0.50

0.25

0

Output Voltage

CE Input Voltage

Inrush Current

Time t (

µs)

50

150

100

250

200

350

400

300

0

µF

µF

µF

40

80

120

160

20

0

60

100

140

180

2.50

2.00

1.50

2.25

1.75

1.25

1.00

0.75

0.50

0.25

0

Output Voltage

CE Input Voltage

Inrush Current

Time t (

µs)

50

150

100

250

200

350

500

400

450

300

0

µF

µF

µF

RP116Z181B/D

40

80

120

160

20

0

60

100

140

180

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

Output Voltage

CE Input Voltage

Inrush Current

µF

µF

µF

Time t (

µs)

100

300

200

500

400

700

600

0