The NCP1252 controller offers everything needed to build cost?

effective and reliable ac?dc switching supplies dedicated to ATX

power supplies. Thanks to the use of an internally fixed timer,

NCP1252 detects an output overload without relying on the auxiliary

Vcc. A Brown?Out input offers protection against low input voltages

and improves the converter safety. Finally a SOIC?8 package saves

PCB space and represents a solution of choice in cost sensitive project.

特性 Features

? Peak Current Mode Control

? Adjustable Switching Frequency up to 500 kHz

? Jittering Frequency ±5 of the Switching Frequency

? Latched Primary Over Current Protection with 10 ms Fixed Delay

? Delay Extended to 150 ms in E Version

? Delayed Operation Upon Start?up via an Internal Fixed Timer

(A, B and C versions only)

? Adjustable Soft?start Timer

? Auto?recovery Brown?Out Detection

? UC384X?like UVLO Thresholds

? Vcc Range from 9 V to 28 V with Auto?recovery UVLO

? Internal 160 ns Leading Edge Blanking

? Adjustable Internal Ramp Compensation

? +500 mA / –800 mA Source / Sink Capability

? Maximum 50 Duty Cycle: A Version

? Maximum 80 Duty Cycle: B Version

? Maximum 65 Duty Cycle: C Version

? Maximum 47.5 Duty Cycle: D & E Versions

? Ready for Updated No Load Regulation Specifications

? SOIC?8 and PDIP?8 Packages

? These are Pb?Free Devices

Typical Applications

? Power Supplies for PC Silver Boxes, Games Adapter...

? Flyback and Forward Converter