© Semiconductor Components Industries, LLC, 2004

October, 2004 − Rev. 8

1

Publication Order Number:

NCP1207/D

NCP1207

PWM Current−Mode

Controller for Free Running

Quasi−Resonant Operation

The NCP1207 combines a true current mode modulator and a

demagnetization detector to ensure full borderline/critical

Conduction Mode in any load/line conditions and minimum drain

voltage switching (Quasi−Resonant operation). Due to its inherent skip

cycle capability, the controller enters burst mode as soon as the power

demand falls below a predetermined level. As this happens at low peak

current, no audible noise can be heard. An internal 8.0

ms timer prevents

the free−run frequency to exceed 100 kHz (therefore below the 150 kHz

CISPR−22 EMI starting limit), while the skip adjustment capability lets

the user select the frequency at which the burst foldback takes place.

The Dynamic Self−Supply (DSS) drastically simplifies the

transformer design in avoiding the use of an auxiliary winding to supply

the NCP1207. This feature is particularly useful in applications where

the output voltage varies during operation (e.g. battery chargers). Due to

its high−voltage technology, the IC is directly connected to the

high−voltage DC rail. As a result, the short−circuit trip point is not

The transformer core reset detection is done through an auxiliary

winding which, brought via a dedicated pin, also enables fast

Overvoltage Protection (OVP). Once an OVP has been detected, the IC

permanently latches off.

Finally, the continuous feedback signal monitoring implemented with

an Overcurrent Fault Protection (OCP) circuitry makes the final design

rugged and reliable.

Features

OFF

Typical Applications

*For additional information on our Pb−Free strategy and soldering details, please

download the ON Semiconductor Soldering and Mounting Techniques

Reference Manual, SOLDERRM/D.

PDIP−8

N SUFFIX

CASE 626

1

8

1

8

SOIC−8

D1, D2 SUFFIX

CASE 751

18

5

3

4

(Top View)

DMG

CS

HV

PIN CONNECTIONS

7

6

2

NC

FB

GND

Drv

MARKING

DIAGRAMS

1207/P = Device Code

A

= Assembly Location

WL, L

= Wafer Lot

YY, Y

= Year

WW, W = Work Week

1207

ALYW

1207P

AWL

YYWW

1

8

http://onsemi.com

Device

Package

ORDERING INFORMATION

NCP1207DR2

SOIC−8

2500/Tape & Reel

NCP1207P

PDIP−8

50 Units/Tube

NCP1207DR2G

SOIC−8

(Pb−Free)

2500/Tape & Reel

†For information on tape and reel specifications,

including part orientation and tape sizes, please

refer to our Tape and Reel Packaging Specifications

Brochure, BRD8011/D.

1

8

NCP1207PG

PDIP−8

(Pb−Free)

50 Units/Tube