IMP525
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
◆ 112V peak-to-peak typical AC output voltage
The IMP525 is an Electroluminescent (EL) lamp driver designed for sys-
tems that must operate below 1 volt. The input supply voltage range is
0.9V to 2.5V. Typical output lamp drive voltage is 112V. 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 dri-
ven 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 under 2µA
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 2µA maximum with a VDD of 1.5V. The
chip can be disabled by connecting RSW, the oscillator frequency setting
resistors, to ground. A disable pad, 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 112V peak-to-peak. This conserves power and
extends battery life.
◆ Clocks and radios
◆ Portable GPS receivers
◆ LCD modules
The IMP525 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
IMP525
Q
Q
6
VB
8
Lamp Drive
Oscillator
REL-OSC
525_01.eps
IMP, Inc.
San Jose, CA
408-432-9100/ www.impweb.com
IMP [ IMP, INC ]
