MIC4827_09 Datasheet, PDF (1/15 Pages) Micrel Semiconductor – Low Input Voltage, 180VPP Output Voltage, EL Driver

MIC4827
Low Input Voltage, 180V_PP Output Voltage,
EL Driver
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-
cellalkaline/NiCad/NiMH battery applications. The
MIC4827 converts a low voltage DC input to a 180V_PP AC
output signal that 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_PP AC signal to drive the
EL lamp and 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_PP regulated AC output waveform
• Independently adjustable EL lamp frequency
• Independently adjustable boost converter frequency
• 0.1µA shutdown current
Applications
• LCD panel backlight
• Cellular phones
• PDAs
• Pager
• Calculators
• Remote controls
• Portable phones
Typical Application
V_IN
C_IN
10µF
L1
220µH
D1
BAV20WS
MIC4827
1 _VDD
332k
2
RSW
3.32M
3
REL
4
GND
SW ⁵
6
CS
8
VA
7
VB
C_OUT
0.033µF/100V
2in² EL LAMP
High Voltage EL Driver
TIME (2ms/div)
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
July 2009
M9999-070709-A
[phone]