IMP527
P
OWER
M
ANAGEMENT
Key Features
Single Cell Battery Powered
Electroluminescent Lamp
Driver/Inverter
ꢀ Wide operating voltage range - from 0.9V to 2.5V
ꢀ Simple design requires few passive components
ꢀ 180V peak-to-peak typical AC output voltage
The IMP527 is an Electroluminescent (EL) lamp driver designed for
systems that must operate down to 1 volt and below. The input supply
voltage range is 0.9V to 2.5V. Typical output lamp drive voltage is 180V.
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.
ꢀ Adjustable output frequency controls lamp
color and power consumption
ꢀ Adjustable converter frequency minimizes
circuit power consumption
ꢀ Disable mode extends battery life
ꢀ Disable current 1µA typical
The circuit requires few external components; one inductor, one diode,
one capacitor and two resistors. The resistors set the frequency for the
two oscillators.
ꢀ Compact MicroSO package option
A disable mode puts the chip into a low current-drain state. When dis-
abled, quiescent current drops to 1µA typical with a VDD of 1.5V. The chip
can be disabled by connecting RSW, the oscillator frequency setting resis-
tor, to ground. A disable pad (active low), accessible only on the die, can
also be used to disable the driver.
Applications
ꢀ Audio/TV remote control units
ꢀ Pagers/Cellular phones
ꢀ PDAs
An internal circuit shuts down the switching regulator when the lamp
drive voltage exceeds 180V peak-to-peak. This conserves power and
extends battery life.
ꢀ Clocks and radios
ꢀ Portable GPS receivers
ꢀ LCD modules
The IMP527 is available in MicroSO and SO-8 packages and in die form.
ꢀ Toys
Block Diagram
4
1
VDD
LX
3
2
5
Switch
Oscillator
RSW-OSC
CS
GND
Q
+
–
7
V
C
A
Regulation
Control
VREF
Q
Bridge
Output
Driver
IMP527
Q
Q
6
VB
8
Lamp Drive
Oscillator
REL-OSC
527_01.eps
© 2000 IMP, Inc.
408-432-9100/www.impweb.com
1
IMP [ IMP, INC ]
