MIC4827_05 Datasheet, PDF (1/13 Pages) Micrel Semiconductor – Low Input Voltage, 180VPP Output Voltage, EL Driver

MIC4827
Micrel
MIC4827
Low Input Voltage, 180V_PP Output Voltage, EL Driver
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_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
• Pagers
• Calculators
• Remote controls
• Portable phones
Ordering Information
Part Number
Standard
Pb-Free
MIC4827BMM MIC4827YMM
Ambient
Temp. Range
–40°C to +85°C
Package
MSOP-8
Typical Application
L1
V_IN
220µH
D1
1N4148
C_IN
10µF
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. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
January 2005
1
MIC4827