IMP560
P
OWER
M
ANAGEMENT
Power Efficient
EL Lamp Driver
The IMP560 is an Electroluminescent (EL) lamp driver designed for sys-
tems with low EL lamp drive voltage requirements. It is ideal for low
ambient light applications or where small lamps are used. With just one-
half the inductor current of the IMP803, the IMP560 reduces system
power consumption and extends battery life. Input supply voltage range
is 2.0V to 6.5V and quiescent current is a low 420µA. Typical EL lamp
drive voltage is ±56V.
All four EL lamp-driving functions are on-chip. These are the switch-
mode power supply, its high-frequency oscillator, the high-voltage
H-bridge lamp driver and its low-frequency oscillator. EL lamps of up to
6nF capacitance can be driven to high brightness.
The circuit requires few external components; a single inductor, a single
diode, two capacitors and three resistors. Two of these resistors set the
frequencies for two internal oscillators. An internal circuit shuts down
the switching regulator when the lamp drive voltage exceeds 120V
peak-to-peak. This conserves power and extends battery life.
A disable mode puts the chip into a low current drain mode. With a 3.0V
supply, quiescent current drops to 200nA maximum, 50nA typical. The
chip is disabled by connecting the oscillator frequency setting resistor
R
SW
to ground.
The IMP560 is available in MicroSO and SO-8 packages and in die or
wafer form.
Key Features
N
112V peak-to-peak typical AC output voltage
N
Low input current (w/inductor current)......12mA
N
Low disabled input current......50nA
N
Wide operating voltage range - from 2.0V to 6.5V
N
Simple design requires few passive components
N
Adjustable output lamp frequency controls lamp
color and power consumption
N
Adjustable converter frequency for minimum
power consumption
N
IMP803 pin-compatible
N
MicroSO package option
Applications
N
N
N
N
N
N
N
Night lights
Automotive displays
Cellular phones
Pagers
Clocks and radios
Portable GPS receivers
LCD module backlights
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
Q
Bridge Output
Driver and
OSC
Q
6
V
B
V
A
–
IMP560
R
EL-OSC
8
Q
560_01.eps
© 2000 IMP, Inc.
408-432-9100/www.impweb.com
1
IMP [ IMP, INC ]
