Datasheet SP4414EN, SP4414EU, SP4414NEB, SP4414UEB Datasheet (Sipex Corporation)

®

SP4414

Low Cost Electroluminescent Lamp Driver

■ Low Power +2.2V to +4.5V Battery
Operation

■ Low-Cost EL Driver Ideal for LED
Backlighting Replacement

■ DC-to-AC Inverter can Produce Over
160VPP for EL Lamps

■ Requires a 32kHz External Clock Signal

■ Synchronize EL Driver Operation to

Existing System Clock for Portable
Applications (i.e. Pagers, Cellular
Phones, PDAs, etc.)

■ Low Current Standby Mode

DESCRIPTION

The SP4414 is a high voltage output DC-AC inverter specifically designed to drive electrolu­minescent lamps to backlight liquid crystal displays, keypads, and backlit readouts used in
battery operated portable equipment. The SP4414 will operate from a +2.2V to +4.5 V battery
source. The device features a low power shutdown mode which draws less than 100nA (typical),
ideal for low power portable products. One external inductor is required to generate the high
voltage AC output. An external clock signal is used to drive the internal control signals for the
coil and EL lamp. The SP4414 is ideal for portable applications such as pagers, cellular
phones, PDAs, and other portable applications using LCDs in dim or low light environments.
The SP4414 is offered in 8-pin SOIC and 8-pin µSOIC packages.

V

BATTERY

V

DD

7

CLK

COIL

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

V

SS

EL2

1
2

3
4

SP4414

8
7

6

5

ELEN
V

DD

EL1
C

INT

10nF

C1

ELEN

CLK

8

1

EL Lamp

2

V

SP4414

SS

COIL

4

C

5

36

EL2EL1

INT

*optional device

L1

2.7mH

*D1

1N4148

C

INT

100pF

1

ABSOLUTE MAXIMUM RATINGS

These are stress ratings only and functional operation of the device at
these ratings or any other above those indicated in the operation sections
of the specifications below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may affect reliability.

Power Supply, V

Input Voltages, ELEN (pin 2)....................................-0.5V to (VDD+0.5V)

Lamp Outputs...............................................................................200V

Operating Temperature...................................................-40˚C to +85˚C

Storage Temperature.....................................................-65˚C to +150˚C

Power Dissipation Per Package

8-pin NSOIC (derate 6.14mW/oC above +70oC)..................................500mW

8-pin µSOIC (derate 4.85mW/oC above +70oC)...................................390mW

.........................................................................7.0V

BATT

SPECIFICATIONS

V

= 3V, L = 2.7mH, C

BATT

= 10nF, and C

LAMP

= 100pF unless otherwise noted.

INT

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DD

2.20.35.4V
5305Am

V

DD

0

52.0-

52.0-

V

DD

V

DD

ycneuqerFrotallicsOlanretxE23zHk

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The information furnished herein by Sipex has been carefully reviewed
for accuracy and reliability. Its application or use, however, is solely the
responsibility of the user. No responsibility for the use of this information
is assumed by Sipex, and this information shall not explicitly or implicitly
become part of the terms and conditions of any subsequent sales
agreement with Sipex. Specifications are subject to change without
prior notice. By the sale or transfer of this information, Sipex assumes
no responsibility for any infringement of patents or other rights of third
parties which may result from its use. No license or other proprietary

PP

rights are granted by implication or otherwise under any patent or
patent rights of Sipex Corporation.

5.4

V

DD

1

V52.0

52.0+

V

V

µA

V

NELE

o

52=T,V0=

C

06Am.ngisedybdeetnarauG

f,ycneuqerFpmaLLE

PMAL

egatloVtuptuOkaeP-ot-kaeP631061V

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

032052072zH

PP

2

PINOUT

CLK

EL2

COIL

PIN ASSIGNMENTS

Pin 1 — CLK — Clock. Connect this input pin

to an external 32KHz clock sets the
frequency of the internal flip flops.

Pin 2 — VSS — Power Supply Common.

Connect to the lowest circuit potential,
typically ground.

Pin 3 — EL2 — Eluminescent Lamp. This is

a lamp driver output pin to connect to the
EL lamp.

Pin 4 — COIL — Coil. The inductor for the

EL lamp is connected from V
input pin.

V

SS

BATTERY

1
2

3
4

SP4414

to this

8

ELEN

7

V

DD

6

EL1

5

C

INT

Pin 5 — C

Connecting a fast recovery diode from
COIL (pin 4) to this input pin increases the
light output of the EL lamp. An integrating
capacitor (100pF) connected from this pin to
ground filters out any coil switching spikes
or ripple present in the output waveform to
the EL lamp.

Pin 6 — EL1 — Eluminescent Lamp. This is

a lamp driver output pin to connect to the
EL lamp.

Pin 7— VDD — Positive Battery Power Supply.

Connect such that +2.2V < V

Pin 8 — ELEN — Eluminescent Lamp Enable.

When driven HIGH, this input pin enables
the EL driver output EL1 and EL2 (pins 6 and
3, respectively) to the EL lamp.

— Integrating Capacitor.

INT

< +4.5V.

DD

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

3

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 180VPP (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.

V

DD

SP4414

7

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

BATTERY

L1

2.7mH

4

COIL

C

10nF

1

*D1

INT

1N4148

C

INT

100pF

* optional device

CLK

C

5

1

FF1

8
ELEN

Q

FF6

Q

2

V

f

COIL

f

LAMP

f

LAMP

SS

SCR1

63

EL1

SCR2

EL2

EL Lamp

Figure 1. Internal Diagram of the SP4414

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

4

Electroluminescent Technology

An EL lamp is basically a strip of plastic that is
coated with a phosphorous material which emits
light (fluoresces) when a high voltage (>40V)
which was first applied across it, is removed or
reversed. Long periods of DC voltages applied
to the material tend to breakdown the material
and reduce its lifetime. With these considerations
in mind, the ideal signal to drive an EL lamp is
a high voltage sine wave. Traditional approaches
to achieving this type of waveform included
discrete circuits incorporating a transformer,
transistors, and several resistors and capacitors.
This approach is large and bulky and can be
difficult to implement in some smaller hand
held equipment. Sipex now offers low power
single chip driver circuits specifically
designed to drive small to medium sized
electroluminescent panels.

V

BATTERY

V

DD

7

C1

10nF

ELEN

CLK

Figure 2. Typical Application Circuit for the SP4414

8

1

EL Lamp

2

V

SS

SP4414

COIL

4

C

INT

5

36

EL2EL1

*optional device

L1

2.7mH

*D1

1N4148

C

INT

100pF

Market Applications

Electroluminescent backlighting is ideal when
used with LCD displays, keypads, or other
backlit readouts. Its main use is to illuminate
displays in dim to dark conditions for momentary
periods of time. EL lamps typically consume
less power than LEDs or incandescent bulbs
making them ideal for battery powered products.
Also, EL lamps are able to evenly light an area
without creating any undesirable "hot spots" in
the display.

THEORY OF OPERATION

The SP4414 is a DC-AC inverter made up of:

1. The Frequency Divider, 2. The Coil, and

3. The Switched H-bridge Network. Further
details of each element follow.

The Oscillator/Frequency Divider

The external oscillator provides the SP4414
with a clock signal used to control the coil
switch (f
and f
equal 32 for the SP4414.

) and the H-bridge network (f

COIL

). The ratio of f

LAMP

COIL/fLAMP

will always

LAMP

The external clock frequency is 32kHz. Figure 1
shows the external clock is internally divided

down by a flip flop to drive the coil at 8kHz.
This signal is divided down by 5 more flip flops
to drive the lamp at 250Hz.

The Coil

The supply V
+4.5V. V
such that I
coil current specification. The majority of the

BATTERY

COIL

can range from +2.2V to

BATTERY

and the coil should be chosen

does not exceed the maximum

current goes through the coil and is typically
much greater than IDD.

The coil is an external component connected
from V
stored in the coil according to the equation
EL=1/2LI
is the product IP = (tON) (VBATTERY - VCE)/

to pin 4 of the SP4414. Energy is

BATTERY

2

where IP, to the first approximation,

P

L), where tON is the time it takes for the coil to
reach its peak current, VCE is the voltage drop
across the internal NPN transistor for f
L is

COIL

, and

the inductance of the coil. When the NPN
transistor switch is off, the energy is forced
through a diode which drives the switched
H-bridge network. This energy recovery is
directly related to the brightness of the EL
lamp output. There are many variations
among coils; magnetic material differences,
winding differences and parasitic capacitances.
For suggested coil suppliers, refer to Page 7.

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

5

The f
the end of the coil at pin 1 to ground or to open
circuit. The f
signal switching at the oscillator frequency,
8kHz. During the time when the f
HIGH, the coil is connected from V
ground and a charged magnetic field is created
in the coil. When the f
ground connection is switched open, the field

signal controls a switch that connects

COIL

signal is a 87% duty cycle

COIL

signal is

COIL

BATTERY

signal is LOW, the

COIL

to

collapses, and the energy in the inductor is
forced to flow toward the high voltage H-bridge
switches. f
(see Figure 4) to the lamp. Each pulse increases

will send an array of charge pulses

COIL

the voltage drop across the lamp in discrete
steps. As the voltage potential approaches its
maximum, the steps become smaller (see Figure 3).

The Switched H-Bridge Network

The H-bridge consists of two SCR structures
that act as high voltage switches. These two
switches control the polarity of how the lamp is
charged. The SCR switches are controlled by
the f
frequency divided by 128. For a 32kHz oscillator,
the 7 flip flops will drive f

signal which is the external oscillator

LAMP

= 250Hz.

LAMP

When the energy from the coil is released, a high
voltage spike is created triggering the SCR
switches. The direction of current flow is
determined by which SCR is enabled. One full
cycle of the H-bridge will create 32 voltage
steps from ground to 80V (typical) on EL1
and EL2 (pins 6 and 3, respectively) which
are 180 degrees out of phase (see Figure 5).
A differential representation of the output is
shown in Figure 6.

Printed Circuit Board Layout Suggestions:

The SP4414's high-frequency operation makes
PC layout important for minimizing ground
bounce and noise. Keep the IC's GND pin and
the ground leads of C1 and C
than 0.2in (5mm) apart. Also keep the

in Figure 2 less

INT

connections to COIL (pin 4) as short as possible.
To maximize output power and efficiency and
minimize output ripple voltage, use a ground
plane and solder the IC's V
the ground plane.

(pin 2) directly to

SS

EL Lamp Driver Design Challenges

There are many variables which can be optimized
for specific applications. The amount of light
emitted is a function of the voltage applied to the
lamp by the inductor, the frequency at which it
is applied, the lamp material, and the lamp size.
Sipex supplies characterization charts to aid the
designer in selecting the optimum circuit
configuration (see Figures 7 to 9).

Sipex will perform customer application
evaluations, using the customer's actual EL
lamp to determine the optimum operating
conditions for specific applications. For
customers considering an EL backlighting
solution for the first time, Sipex is able to offer
retrofitted solutions to the customer's existing
LED or non-backlit product for a thorough
electrical and cosmetic evaluation. Please
contact your local Sales Representative for
Sipex or the Sipex factory directly to initiate
this valued service.

Fine Tuning Performance

Circuit performance of the SP4414 can be
improved with some of the following
suggestions:

Increase EL Lamp Light Output: By
connecting a fast recovery diode from COIL
(pin 4) to C
switched H-bridge network is bypassed resulting

(pin 5), the internal diode of the

INT

in an increase in light output at the EL lamp. We
suggest a fast recovery diode, such as the industry
standard 1N4148, be used for D1. This circuit
connection can be found in Figure 2.

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

6

Coil Manufacturers

Hitachi Metals
Material Trading Division
2101 S. Arlington Heights Road,
Suite 116
Arlington Heights, IL 60005-4142
Phone: [phone] Ext. 12
[phone] Ext. 12
Fax: [phone]

Hitachi Metals Ltd. Europe
Immernannstrasse 14-16, 40210
Dusseldorf, Germany
Contact: Gary Loos
Phone: [phone]
Fax: [phone]

Hitachi Metals Ltd.
Kishimoto Bldg. 2-1, Marunouchi
2-chome, Chiyoda-Ku, Tokyo, Japan
Contact: Mr. Noboru Abe
Phone: [phone]
Fax: [phone]

Hitachi Metals Ltd. Singapore
78 Shenton Way #12-01,
Singapore 079120
Contact: Mr. Stan Kaiko
Phone: [phone]
Fax: [phone]

Hitachi Metals Ltd. Hong Kong
Room 1107, 11/F., West Wing,
Tsim Sha. Tsui Center 66
Mody Road, Tsimshatsui East,
Kowloon, Hong Kong
Phone: [phone]
Fax: [phone]

Toko America Inc.
1250 Feehanville Drive
Mt. Prospect, IL, 60056 U.S.A.
Phone: [phone]
Fax: [phone]

Toko Inc. Europe
Burgmullerstr. 7, D-40235
Dusseldorf 1, FR Germany
Phone: [phone]
Fax: [phone]

Toko Inc. Japan
1-17, Higashi-Yukigaya
2-chome, Ohta-ku,
Tokyo 145 Japan
Phone: [phone]
Fax: [phone]

Toko Inc. Singapore
No. 1 Lorong 2. Toa Pavoh.
#03-00, Singapore, 319637
Phone: [phone]
Fax: [phone]

Toko Inc. Hong Kong
45 Hoi Yuen Road, Yau Lee
Centre, 7th, 8th, & 9th Fl.,
Kwun-Tong Kowloon,
Hong Kong
Phone: [phone]
Fax: [phone]

Sumida Electric Co., LTD.
5999, New Wilke Road,
Suite #110
Rolling Meadows, IL, 60008 U.S.A.
Phone: [phone]
Fax: [phone]

Sumida Electric Co., LTD.
4-8, Kanamachi 2-Chrome,
Katsushika-ku, Tokyo 125 Japan
Phone: [phone]
Fax: [phone]

Sumida Electric Co., LTD.
Block 15, 996, Bendemeer Road
#04-05 to 06, Singapore 339944
Republic of Singapore
Phone: [phone]
Fax: [phone]

Sumida Electric Co., LTD.
14 Floor, Eastern Center, 1065
King's Road, Quarry Bay,
Hong Kong
Phone: [phone]
Fax: [phone]

Murata
2200 Lake Park Drive, Smyrna
Georgia 30080 U.S.A.
Phone: [phone]
Fax: [phone]

Murata European
Holbeinstrasse 21-23, 90441
Numberg, Postfachanschrift 90015
Phone: [phone]
Fax: [phone]

Murata Taiwan Electronics
225 Chung-Chin Road, Taichung,
Taiwan, R.O.C.
Phone: [phone]
Fax: [phone]

Murata Electronics Singapore
200 Yishun Ave. 7, Singapore
2776, Republic of Singapore
Phone: [phone]
Fax: [phone]

Murata Hong Kong
Room 709-712 Miramar Tower, 1
Kimberly Road, Tsimshatsui,
Kowloon, Hong Kong
Phone: [phone]
Fax: [phone]

Polarizers/transflector Mnfg.

Nitto Denko
Yoshi Shinozuka
Bayside Business Park 48500
Fremont, CA. 94538
Phone: [phone]
Fax: [phone]

Top Polarizer- NPF F1205DU
Bottom - NPF F4225
or (F4205) P3 w/transflector

Transflector Material
Astra Products
Mark Bogin
P.O. Box 479
Baldwin, NJ 11510
Phone [phone]
Fax [phone]

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

EL Lamp manufacturers

Leading Edge Ind. Inc.
11578 Encore Circle
Minnetonka, MN 55343
Phone [phone]

Midori Mark Ltd.
1-5 Komagata 2-Chome
Taita-Ku 111-0043 Japan
Phone: [phone]

Luminescent Systems Inc. (LSI)
4 Lucent Drive
Lebanon, NH. 03766
Phone: [phone]
Fax: [phone]

NEC Corporation
Yumi Saskai
7-1, Shiba 5 Chome, Minato-ku,
Tokyo 108-01, Japan
Phone: [phone]
Fax: [phone]

Seiko Precision
Shuzo Abe
1-1, Taihei 4-Chome,
Sumida-ku, Tokyo, 139 Japan
Phone: [phone]
Fax: [phone]

Gunze Electronics
2113 Wells Branch Parkway
Austin, TX 78728
Phone: [phone]
Fax: [phone]

7

V

=110V (max)

PEAK

EL1 output; 16 charge steps per half cycle

Figure 3. EL Output Voltage in Discrete Steps at EL1 Output

16 coil pulses per half cycle; 87% duty cycle.

Figure 4. Voltage Pulses Released from the Coil to the EL Driver Circuitry

EL1 Output

EL2 Output

Figure 5. EL Voltage Waveforms from the EL1 and EL2 Outputs

EL1 Output

VPP=220V (max)

EL2 Output

Differential Representation E

.

12

Figure 6. EL Differential Output Waveform of the EL1 and EL2 Outputs

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

8

The following performance curves are intended to give the designer a relative scale from which to optimize
specific applications. Absolute measurements may vary depending upon the brand of components chosen.

35
30
25
20
15

ICC (mA)

10

5
0

1.5 2 2.5 3 3.5 4 5

Lamp Size (sq in)

Figure 7. I

vs Lamp Size

TOTAL

250
200
150
100

50

Output V oltage (VPP)

0

1234567

Figure 8. Output Voltage vs Lamp Size

Lamp Size (sq in)

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

9

The following performance curves are intended to give the designer a relative scale from which to optimize
specific applications. Absolute measurements may vary depending upon the brand of components chosen.

4

3.5
3

2.5
2

1.5
1

Luminance (fL)

0.5
0

1234567

Lamp Size (sq in)

Figure 9. Luminance (Foot-Lamberts) vs. Lamp Size

14
12

>

10

8
6
4
2

Luminance (cd/m 2)

0

1234567

Lamp Size (sq in)

Figure 10. Luminance (candela per meter square) vs. Lamp Size

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

10

The following performance curves are intended to give the designer a relative scale from which to optimize
specific applications. Absolute measurements may vary depending upon the brand of components chosen.

12

10

8

L=1mH (34

6

Peak Volta ge (V)

4

2

0

12345678910

Figure 11. Peak Voltage vs. Frequency

Frequency (kHz)

L=2.7mH (44
L=4.8mH (60

80

70

60

50

40

30

Supply Current (mA)

20

10

0

10 20 30 40 50 60 70 80 90 100

Frequency (kHz)

L=1mH (34
L=2.7mH (44 Ohms)
L=4.8mH (60 Ohms)

Figure 12. Supply Current vs. Frequency

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

11

The following performance curves are intended to give the designer a relative scale from which to optimize
specific applications. Absolute measurements may vary depending upon the brand of components chosen.

7.00

6.00

5.00

4.00

3.00

Brightness (fL)

2.00

1.00

0.00
10 20 30 40 50 60 70 80 90 100

Figure 13. Brightness vs. Frequency

Frequency (kHz)

L=1mH (34 Ohms)
L=2.7mH (44 Ohms)
L=4.8mH (60 Ohms)

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

12

8-pin NSOIC

All package dimensions in inches

8-pin µSOIC

0.0256
BSC

SP4414EU

1

2

0.116

±0.004

0.013
±0.005

0.118

±0.004

0.118

±0.004

0.004

±0.002

0.034

±0.004

0.040

±0.003

SP4414EN

1

0.189/0.197

0.0965

0.020

±0.003

0.020

0.228/0.2440.150/0.157

0.014/0.019

0.053/0.069

0.050 BSC

95 NSOIC devices per tube, no minimum quantity 50 µSOIC devices per tube

0.012
±0.003

0.16

±0.003

R .003

12.0˚
±4˚

12.0˚
±4˚

0.008
0˚ - 6˚

0.006

±0.006

0.006

±0.006

0.0215

±0.006

0.01

0.037
Ref

0.116

±0.004

0.118

±0.004

3.0˚
±3˚

P

W

8-pin NSOIC 13” reels: P = 8mm, W = 12mm

8-pin µSOIC 13” reels: P = 8mm, W = 12mm

Pkg. min qty per reel std qty per reel max qty per reel
EN 500 2500 3000

EU 500 2500 3000

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

13

ORDERING INFORMATION

Model Temperature Range Package Type

SP4414EN . ............................................ -40˚C to +85˚C ......................................... 8-Pin NSOIC

SP4414EU . ............................................ -40˚C to +85˚C ......................................... 8-Pin µSOIC

SP4414NEB..................................................... N/A ........................................... Evaluation Board

SP4414UEB..................................................... N/A ........................................... Evaluation Board

Please consult the factory for pricing and availability on a Tape-On-Reel option.

Corporation

SIGNAL PROCESSING EXCELLENCE

Sipex Corporation
Headquarters and

Sales Office

22 Linnell Circle
Billerica, MA 01821
TEL: [phone]
FAX: [phone]
e-mail: [e-mail]

Sales Office

233 South Hillview Drive
Milpitas, CA 95035
TEL: [phone]
FAX: [phone]

Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the
application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.

SP4414DS/17 SP4414 Electroluminescent Lamp Driver © Copyright 2000 Sipex Corporation

14