January 2005

1

MIC4827

MIC4827

Micrel

MIC4827

Low Input Voltage, 180V

Final Information

General Description

Micrel’s MIC4827 is a high output voltage, DC to AC con-

verter, designed for driving EL (Electroluminescent) lamps.

The device operates from an input voltage range of 1.8V to

5.5V, making it suitable for 1-cell Li Ion and 2- or 3-cell

alkaline/NiCad/NiMH battery applications. The MIC4827 con-

verts a low voltage DC input to a 180V

drives the EL lamp.

The MIC4827 is comprised of two stages: a boost stage, and

an H-bridge, lamp driver, stage. The boost stage steps the

input voltage up to +90V. The H-bridge stage then alternately

switches the +90V output to each terminal of the EL lamp,

thus creating a 180V

generate light.

The MIC4827 features separate oscillators for the boost- and

H-bridge stages. External resistors independently set the

operating frequency of each stage. This flexibility allows the

EL lamp circuit to be optimized for maximum efficiency and

brightness.

The MIC4827 uses a single inductor and a minimum number

of external components, making it ideal for portable, space-

sensitive applications.

The MIC4827 is available in an 8-pin MSOP package with an

ambient temperature range of –40°C to +85°C.

Features

• 1.8V to 5.5V DC input voltage

• 180V

• Independently adjustable EL lamp frequency

• Independently adjustable boost converter frequency

• 0.1µA shutdown current

Applications

• LCD panel backlight

• Cellular phones

• PDAs

• Pagers

• Calculators

• Remote controls

• Portable phones

Ordering Information

Part Number

Ambient

Standard

Pb-Free

Temp. Range

Package

MIC4827BMM

MIC4827YMM

–40°C to +85°C

MSOP-8

Typical Application

332k

3.32M

0.033µF/100V

D1

1N4148

L1

220µH

15

6

8

7

2

3

4

SW

CS

VA

VB

VDD

RSW

REL

GND

MIC4827

10µF

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

TIME (2ms/div)

High Voltage EL Driver