SP4414DS/17

SP4414 Electroluminescent Lamp Driver

© Copyright 2000 Sipex Corporation

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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

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.

Figure 1. Internal Diagram of the SP4414

f

COIL

f

LAMP

f

LAMP

FF6

Q

Q

V

BATTERY

L1

2.7mH

EL Lamp

SCR1

SCR2

63

2

V

SS

C

INT

COIL

EL2

EL1

C

INT

100pF

FF1

ELEN

SP4414

10nF

*D1

1N4148

V

DD

1

CLK

8

4

5

* optional device

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