MIC4827
Micrel
MIC4827
Low Input Voltage, 180VPP Output Voltage, EL Driver
Final Information
General Description
Features
• 1.8V to 5.5V DC input voltage
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/NiMHbatteryapplications.TheMIC4827con-
• 180V regulated AC output waveform
PP
• Independently adjustable EL lamp frequency
• Independently adjustable boost converter frequency
• 0.1µA shutdown current
vertsalowvoltageDCinputtoa180V ACoutputsignalthat
drives the EL lamp.
PP
Applications
• LCD panel backlight
• Cellular phones
• PDAs
• Pagers
• Calculators
The MIC4827 is comprised of two stages: a boost stage, and
an H-bridge, lamp driver, stage. The boost stage steps the
inputvoltageupto+90V. TheH-bridgestagethenalternately
switches the +90V output to each terminal of the EL lamp,
thus creating a 180V AC signal to drive the EL lamp and
PP
• Remote controls
• Portable phones
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.
Ordering Information
Part Number
Standard Pb-Free
Ambient
Temp. Range
Package
The MIC4827 uses a single inductor and a minimum number
of external components, making it ideal for portable, space-
sensitive applications.
MIC4827BMM MIC4827YMM –40°C to +85°C MSOP-8
The MIC4827 is available in an 8-pin MSOP package with an
ambient temperature range of –40°C to +85°C.
Typical Application
L1
220µH
D1
1N4148
VIN
COUT
0.033µF/100V
CIN
10µF
MIC4827
1
2
3
4
5
6
8
7
VDD
SW
332k
RSW
REL
CS
VA
VB
3.32M
GND
2in2 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
January 2005
1
MIC4827