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DS-RS2012-0

3

July, 2008

www.Orister.com

RS2012

Low Power OFF-Line SMPS Primary Switcher

The RS2012 combines a dedicated current mode PWM controller with a high voltage Power MOSFET on the same

silicon chip.

Typical applications cover off line power supplies for battery charger adapters, standby power supplies for TV or

monitors, auxiliary supplies for motor control, etc. The internal control circuit offers the following benefits:

◎

Large input voltage range on the VCC pin accommodates changes in auxiliary supply voltage. This feature is

well adapted to battery charger adapter configurations.

◎

Automatic burst mode in low load condition.

◎

Over voltage protection in HICCUP mode.

Features

◎

85V to 265V wide range AC voltage input

◎

A 700V MOSFET on the same silicon chip

◎

Auto start up with high voltage current source

◎

PWM with current mode control

◎

9V to 38V wide range VCC voltage

◎

Fixed 60KHz switching frequency

◎

Automatic skip cycle mode in low load condition

◎

Over temperature, over current and over voltage protection

◎

Auxiliary under voltage lockout with hysteresis

Applications

◎

Power AC/DC Adapters for Chargers

◎

DVD/VCD power supplies

◎

Electromagnetic Oven power supplies

◎

Air Conditioner power supplies

◎

STB power supplies

◎

AC/DC LED Driver Applications

Pin Configurations

TYPE

SOP-8L

DIP-8L

European (195-265 Vac)

8W

13W

US (85-265 Vac)

5W

8W

Pin Number

Pin Name

Function Description

1, 2

GND

Sense FET source terminal on primary side and internal control ground.

3

COMP

Feedback input defines the peak drain MOSFET current.

4

VCC

Positive supply voltage input. Although connected to an auxiliary transformer winding,

current is supplied from SW via an internal switch during startup (see Internal Block

Diagram section). It is not until VCC reaches them UVLO upper threshold (14.5V)

that the internal start-up switch opens and device power is supplied via the auxiliary

transformer winding.

5, 6, 7, 8

SW

The SW pin is designed to connect directly to the primary lead of the transformer and

is capable of switching a maximum of 700V.