IMP803
P
OWER
M
ANAGEMENT
High-Voltage EL Lamp Driver
The IMP803 is an Electroluminescent (EL) lamp driver with the four EL
lamp driving functions on-chip. These are the switch-mode power sup-
ply, its high-frequency oscillator, the high-voltage H-bridge lamp driver
and its low-frequency oscillator. The IMP803 drives EL lamps of up to
30nF capacitance to high brightness; EL lamps with capacitances greater
than 30nF can be driven, but will be lower in light output. The typical
regulated output voltage that is applied to the EL lamp is 180V peak-to-
peak. The circuit requires few external components, a single inductor,
single diode, two capacitors and three resistors. Two of these resistors
set the frequency for two internal oscillators.
The IMP803 operates over a 2.0V to 6.5V supply voltage range. A
regulated, low-power source can supply the low quiescent current of the
IMP803. The inductor may be driven from an independent, unregulated
supply voltage in dual supply applications.
An internal circuit shuts down the switching regulator when the lamp
drive voltage reaches 180V peak-to-peak. This conserves power and
extends battery life.
The IMP803 is available in MicroSO and SO-8 packages and in die or
wafer form.
Key Features
N
Low Power: 420碌A typical V
DD
current
N
Wide operating voltage range - from 2.0V to 6.5V
N
180V peak-to-peak typical AC output voltage
N
Large output load capability - drive lamps
with more than 30nF capacitance
N
Adjustable output lamp frequency for control of
lamp color, lamp life, and power consumption
N
Adjustable converter frequency to minimize
power consumption
N
Device can be Enabled/Disabled
N
Low quiescent current 鈥?20nA (disabled)
N
High-Voltage CMOS Process
N
MicroSO package option
Applications
N
N
N
N
N
N
N
GPS units/Pagers/Cellular phones
PDAs/Handheld computers
Safety illumination
Portable instrumentation
Battery-operated displays
LCD modules
Toys
4
L
X
C
S
Block Diagram
V
DD
1
R
SW-OSC
GND
2
Switch
Oscillator
3
5
+
C
Regulation
Control
Q
7
V
REF
Bridge
Output
Driver
Q
6
V
B
Q
V
A
鈥?/div>
IMP803
R
EL-OSC
8
Lamp Drive
Oscillator
Q
803_01.eps
漏 2000 IMP, Inc.
408-432-9100/www.impweb.com
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