4

General description

4.1

Block diagram

VCC

DRAIN

Internal Supply bus

REGULATOR

4V

HV

Start up

THERMAL

DIODE

(OTP)

GND

HV DISABLE

LOGIC

SOFT START

JITTERED

OSCILLATOR

E/A

+

-

+

-

FB

PWM

-

+

TURN ON

LOGIC

COMP

OCP

UVLO VCC

VCC_clamp

LEB

S

R

Q

OTP

OCP

-

+

LIGHT LOAD PFM

PROTECTION

LOGIC

OVP LOGIC

OVP

+

-

UVP

S

R

Q

IC DISABLE

LOGIC

IC_DIS

IC_DIS

IC_DIS_SET

IC_DIS_RESET

+

4.2

Typical power capability

Adapter (1)

Open Frame (2)

Adapter (1)

Open Frame (2)

27 W

31 W

16 W

19 W

1. Typical continuous power in non-ventilated enclosed adapter measured at 50°C ambient.

2. Maximum practical continuous power in an open frame design at 50°C ambient, with adequate heat sinking.

VIPER31

General description

DS13285 - Rev 3

page 13/40