NCP1378DR2 View Datasheet(PDF) - ON Semiconductor

Part Name

Description

Manufacturer

NCP1378DR2

PWM Current−Mode Controller for Free−Running Quasi−Resonant Operation

ON Semiconductor 

NCP1378

PWM Current−Mode

Controller for Free−Running

Quasi−Resonant Operation

The NCP1378 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 transformer core reset detection is done through an auxiliary

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

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

permanently latches off.

The NCP1378 also features an efficient protective circuitry that, in

presence of an overcurrent condition, disables the output pulses and

enters a safe burst mode, trying to restart. Once the default has gone,

the device auto−recovers. Finally an internal 1.0 ms Soft−Start

eliminates the traditional startup stress.

The NCP1378 is tailored for low voltage applications having

UVLO thresholds of 8.4 V (on) and 7.5 V (off).

Features

• Free−Running Borderline/Critical Mode Quasi−Resonant Operation

• Latched Overvoltage Protection

• Auto−Recovery Short−Circuit Protection Via UVLO Crossover

• Current−Mode with Adjustable Skip Cycle Capability

• Internal 1.0 ms Soft−Start

• Internal Temperature Shutdown

• Internal Leading Edge Blanking

• 500 mA Peak Current Source/Sink Capability

• External Latch Triggering, e.g. Via Overtemperature Signal

• Direct Optocoupler Connection

• SPICE Models Available for TRANsient Analysis

• Internal 8.0 ms Minimum TOFF

• Pb−Free Packages are Available*

Typical Applications

• Battery−Based Operations

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

download the ON Semiconductor Soldering and Mounting Techniques Reference

Manual, SOLDERRM/D.

http://onsemi.com

8

1

SOIC−8

D SUFFIX

CASE 751

MARKING

DIAGRAMS

8

1378

ALYW

G

1

8

1

PDIP−7

P SUFFIX

CASE 626B

1378P

AWL

YYWWG

1

A

L, WL

Y, YY

W, WW

G or G

= Assembly Location

= Wafer Lot

= Year

= Work Week

= Pb−Free Package

PIN CONNECTIONS

Dmg 1

8 HV

FB 2

CS 3

GND 4

6 VCC

5 Drv

(Top View)

ORDERING INFORMATION

Device

NCP1378DR2

Package

SOIC−8

Shipping†

2500 Tape & Reel

NCP1378DR2G

NCP1378P

SOIC−8

(Pb−Free)

PDIP−7

2500 Tape & Reel

50 Units/Rail

NCP1378PG

PDIP−7

(Pb−Free)

50 Units/Rail

†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.

© Semiconductor Components Industries, LLC, 2006

1

October, 2006 − Rev. 4

Publication Order Number:

NCP1378/D

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