IX9908 datasheet(6/10 Pages) IXYS

6 / 10 page

INTEGRATED CIRCUITS DIVISION

IX9908

www.ixysic.com

R01

2. Functional Description

Figure 1. IX9908 Block Diagram

2.1 Internal Supply Voltage During Start-Up

The IX9908 integrates a high voltage startup cell. This

cell provides a constant current to charge the VCC

capacitor (CVCC) during the Power-up phase of

operation. Once the main input voltage is applied, a

rectified voltage will be across CIN.

Figure 2. Start-Up

The start-up cell will sense this voltage, and source a

constant current of approximately 10 mA to CVCC. This

current will remain until VCC reaches VVCC_on or 18V

nominal. It will then be switched off, and a soft start

sequence will begin. VCC will then sag as the CVCC

capacitor supplies current to power the device, and is

not yet receiving energy from the auxiliary winding.

Once the output voltage is high enough the auxiliary

winding will provide energy to CVCC and the VCC

voltage will reach a constant value. This value

depends on the output load and transformer

characteristics.

Ringing

Suppress

Blanking

Reference Voltage

Generator

Vcc Monitor

Over - Under

Voltage Lockout

High Voltage

Startup

Gate

Control

Logic

Soft-Start

Control

Analog

Mux

LPF

Leading

Edge

Blanking

PFC

Leading

Edge

Blanking

Foldback

Sense Amp

Foldback

Correction

Over-Temp

Sensor

Leading

Edge

Blanking

ZCV

GND

Vcc

Over-Voltage Protection

Shorted Winding Detection

VCC_on

VCC_off

startup

tstartup =

VCC_on • CVCC

ICC_CHARGE

IX9908 Datasheet(PDF) 6 Page - IXYS Corporation

IX9908 Datasheet(HTML) 6 Page - IXYS Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10

Datasheet Download

Link URL