Preliminary

IXYS

MX841

1

03/10/05

Drawing No. 17023

www.ixys.net

MX841

White LED Step-Up Converter

Features:

• 1.1V to 5.5V Input Range

• 2 Amp Peak Switch Current

• High Efficiency > 80%

• 20V Maximum Output with Over-Voltage

Protection

• LED Intensity Control

• 1.0 MHz Fixed Frequency Switching

• 8 Lead SOIC Package

Applications:

• White LED Display Backlighting

-

Low Voltage: Mobile Phones, PDA’s,

MP3 Players, Digital Cameras

-

High Drive Current: Vehicle

Instrumentation Panels

Ordering Information

Part No.

Description

Qty

100

2500

2500

General Description

The MX841 is a fixed frequency, constant current

source step-up DC/DC converter. The output current

is directly regulated making the MX841 ideal for

driving series connected white light emitting diodes

(LED’s) in backlight applications. The MX841

powers up to 3 series white LED’s at 1.1V, and 20

series/parallel white LED’s at 5.0V.

The MX841 features a 1.0MHz switching frequency

to accommodate the use of small capacitors and a

small inductor necessary in size sensitive portable

applications. Light intensity and shutdown are

conveniently controlled by a single analog voltage.

Power efficiency and battery life are extended

channel MOSFET switch.

The MX841 is designed to operate over a

temperature range of -40°C to +85°C, and is

available in an SOIC-8 Package, with or without an

Exposed Pad in Tube or on Tape and Reel.

(Alternate package types available upon request).

Functional Block Diagram

Typical Application

MX841

CTRL

Vbattery

OVD

Isense

CTL/

SLEEP

Rsense

Vboost

Analog

GND

Switch

GND

3

14

5

6

8

7

2

osc

err amp/

comparato

r

sleep de

t

bias gen

VDD

drive

r

Isense

OVD

band gap

+

compar

e

Gnd

Switch

SW

SW

CTL/SLEEP

Analog

Gnd