SP4414 Datasheet, PDF (4/14 Pages) Sipex Corporation – Low Cost Electroluminescent Lamp Driver

DESCRIPTION
The SP4414 Electroluminescent Lamp Driver
is a low-cost low power device ideal for the
replacement of LED backlighting designs. The
32kHz external oscillator drives controls signals
for the coil and EL lamp circuitry. The SP4414
32kHz operation is synchronized with existing
system clock designs in single cell applications
such as pagers, cell phones, PDAs, etc.
The SP4414 contains a DC-AC inverter that
can produce an AC output of 180V_PP (maximum)
from a +2.2V to +4.5V input voltage. An
external clock provides the SP4414 with
the control signals for the coil and EL lamp.
An internal block diagram of the SP4414 can
be found in Figure 1.
The SP4414 is built on Sipex's dielectrically
isolated BiCMOS process that provides the
isolation required to separate the high voltage
AC signal used to drive the EL lamp from the
low voltage logic and signal processing circuitry.
This ensures latch-up free operation in the
interface between the low voltage CMOS
circuitry and the high voltage bipolar circuitry.
A total of only four external components are
required for the standard operation of the
SP4414: an inductor, a fast recovery diode, and
two capacitors. A diagram of the SP4414 in a
typical application can be found in Figure 2.
V_DD
SP4414
7
CLK _{1 FF1}
f_COIL
Q
FF6
Q
f_LAMP
f_LAMP
8
ELEN
2
V_SS
Figure 1. Internal Diagram of the SP4414
SCR1
V_BATTERY
4 COIL
L1
2.7mH
5 ^CINT
SCR2
*D1
1N4148
C_INT
100pF
C1
10nF
6
3
EL1
EL2
EL Lamp
* optional device
SP4414DS/17
SP4414 Electroluminescent Lamp Driver
4
© Copyright 2000 Sipex Corporation