NCP1205(2002) Просмотр технического описания (PDF) - ON Semiconductor

Номер в каталоге

Компоненты Описание

производитель

NCP1205
(Rev.:2002)

Single Ended PWM Controller Featuring QR Operation and Soft Frequency Foldback

ON Semiconductor 

NCP1205

PIN CONNECTIONS

HV 1

Demag 2

FB 3

Ct 4

8 VCC

7 Drive

6 Isense

5 GND

PDIP–8

HV 1

NC 2

Demag 3

FB 4

Ct 5

OVP 6

NC 7

14 NC

13 VCC

12 Drive

11 Isense

10 GND

9 NC

8 NC

PDIP–14

PIN FUNCTION DESCRIPTION

Pin No.

DIP8 DIP14 Pin Name

1

1

HV

Function

Start–up rail

2

3

Demag

Zero primary–current

detection

3

4

FB

Feedback signal to

control the PWM

4

5

Ct

Timing capacitor

5

10

NA

6

Gnd

OVP

The IC’s ground

Overvoltage input

6

11

7

12

8

13

Isense

Drv

VCC

The primary–current

sensing pin

This pin drives the

external switcher

Powers the IC

1. DIP14 has different pinouts. Please see Pin Connections.

2. Pin 2, 7, 8, 9 and 14 are nonconnected on DIP14.

Description

Connected to the rectified HV rail, this pin provides a charging path to

VCC bulk capacitor.

This pin ensures the re–start of the main switcher when operating in

free–run.

This level modulates the peak current level in free–running operation

and modulates the frequency in VFM operation.

By adding a capacitor from Ct to the ground, the user selects the

minimum/maximum operating frequency.

–

By applying a 2.8 V typical level on this pin, the IC is permanently

latched–off until VCC falls below UVLOL.

This pin senses the primary current via an external shunt resistor.

The IC is able to deliver or absorb 250 mA peak currents while

delivering a clamped driving signal.

A positive voltage up to 40 V typical can be applied upon this pin

before the IC stops.

http://onsemi.com

2

Share Link: