MIC4826
Micrel
MIC4826
Low Input Voltage, 160V
PP
Output Voltage, EL Driver
General Description
Micrel’s MIC4826 is a high output voltage, DC to AC converter,
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 MIC4826 converts
a low voltage DC input to a 160V
PP
AC output signal that
drives the EL lamp.
The MIC4826 is comprised of two stages: a boost stage, and
an H-bridge, lamp driver, stage. The boost stage steps the
input voltage up to +80V. The H-bridge stage then alternately
switches the +80V output to each terminal of the EL lamp,
thus creating a 160V
PP
AC signal to drive the EL lamp and
generate light.
The MIC4826 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 MIC4826 uses a single inductor and a minimum number
of external components, making it ideal for portable, space-
sensitive applications.
The MIC4826 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
160V
PP
regulated AC output waveform
Independently adjustable EL lamp frequency
Independently adjustable boost converter frequency
0.1µA shutdown current
LCD panel backlight
Cellular phones
PDAs
Pagers
Calculators
Remote controls
Portable phones
Applications
Ordering Information
Part Number
Standard
Pb-Free
MIC4826BMM
Temp. Range
–40°C to +85°C
Package
MSOP-8
MIC4826YMM
Typical Application
L1
220µH
MIC4826
1
442k
2M
VDD
RSW
REL
GND
SW
CS
VA
VB
5
6
8
2
3
4
2in
2
EL LAMP
TIME (2ms/div)
High Voltage EL Driver
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
March 2009
1
V
A
Ð V
B
(50V/div)
7
V
B
(50V/div)
C
IN
10µF
C
OUT
0.01µF/100V
V
A
(50V/div)
V
IN
D1
BAV19WS
V
IN
= 3.0V
L = 220µH�½
C
OUT
= 0.01µF
Lamp = 2in
2
�½
R
SW
= 332k�½
R
EL
= 3.32M
MIC4826
MICREL [ MICREL SEMICONDUCTOR ]
