SP4412ADS/12
SP4412ACN Electroluminescent Lamp Driver
Copyright 2000 Sipex Corporation
1
s
2.2 V- 3.6 V Battery Operation
s
50 nA Maximum Standby Current
(10 nA typical)
s
High Voltage Output Typical 160 V
PP
s
External Oscillator Required
s
Enable Control Pin
APPLICATIONS
s
Watches
s
Pagers
s
Backlit LCD Displays
SP4412A
Electroluminescent Lamp Driver
DESCRIPTION
The SP4412A is a high voltage output DC-AC converter that can operate from a 2.2V-3.6V
power supply. The SP4412A is capable of supplying up to 250 V
PP
signals, making it ideal
for driving small electroluminescent lamps. The device features 10 nA (typical) standby
current, for use in low power portable products. An inductor is used to generate the high
voltage, and an external oscillator is needed as a clock source. The SP4412A is offered in
an 8-pin narrow SOIC package or an 8-pin
SOIC package. For delivery in die form, please
consult the factory.
SP4412A Block Diagram
HON
V
DD
Osc Input
V
SS
COIL
EL2
EL1
SP4412A
8
7
4
3
2
1
5
6
No Connect
SP4412ADS/12
SP4412ACN Electroluminescent Lamp Driver
Copyright 2000 Sipex Corporation
2
NOTES:
1. Dimensions are in microns unless otherwise noted (mils)
2. Bonding pads are 125 x 125 microns typical
3. Outside dimensions are maximum including scribe area
4. Die thickness is 15 mils +/- 1
5. Pad center coordinates are relative to the die center.
Measured from center of Pads.
1397
(55)
Coil
Lamp 2
Lamp 1
Clk.
V
DD
V
SS
Y
X
(0,0)
1143
(45)
HON
SPECIFICATIONS
T= 25
C; V
DD
= 3.0V; Lamp Capacitance = 2000pF; Coil = 30 mH at 125 Ohms; External Oscillator = 32768Hz (unless otherwise noted).
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.
V
DD
..................................................................................................5.0 V
Input Voltages/Currents
HON (pin 1).........................................-0.5V to (V
DD
+0.5V)
COIL (pin 3)..............................................................60mA
Lamp Outputs...............................................................................250V
PP
Storage Temperature.....................................................-65C to +150C
Power Dissipation Per Package
8-pin NSOIC (derate 6.14mW
o
C above +70
o
C)...................................500mW
8-pin
SOIC (derate 4.85mW
o
C above +70
o
C)....................................390mW
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 rights are granted by implication or otherwise under any
patent or patent rights of Sipex Corporation.
BONDING DIAGRAM
PIN
X
Y
CLK
218.5
555.5
HON
418.5
555.5
V
DD
418.5
339.5
EL2
-178.0
-555.5
EL1
95.5
-555.5
COIL
-416.0
-555.5
-416.0
219.0
R
E
T
E
M
A
R
A
P
.
N
I
M
.
P
Y
T
.
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D
5
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V
=
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3
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2
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D
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A
n
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V
0
=
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f
=
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M
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2
3
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2
9
1
8
z
H
z
H
8
6
7
2
3
=
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7
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1
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P
P
V
SS
SP4412ADS/12
SP4412ACN Electroluminescent Lamp Driver
Copyright 2000 Sipex Corporation
3
THEORY OF OPERATION
The SP4412A is made up of three basic circuit
elements, a divider chain, a coil, and a switched
H-bridge network. The countdown chain
provides the circuit with a clock source used to
control the charge and discharge phases for the
coil and lamp. An external oscillator is required
and is delivered to pin 3 of the SO-8 package or
to the "Osc in" pad of the bare die. The chart on
page 6 shows the effect of variations in coil
values used. If a clock frequency other than
32kHz is used, the output of the driver as well as
the amount of current used, will be effected.
The suggested oscillator frequency is 32,768Hz.
This clock frequency is internally divided to
create two internal control signals, f
COIL
and
f
LAMP
. The output is internally divided down by
7 flip flops; therefore, a 32,768Hz signal will be
divided into the following frequencies; 32, 16,
8, 4, 2, 1, 0.5 and 0.25kHz. The second flip flop
output (8 kHz) is used to drive the coil (see
figure 2 on page 7) and the seventh flip flop
output (256 Hz) is used to drive the lamp.
Although the oscillator frequency can be varied
to optimize the lamp output, the ratio of f
COIL
/
f
LAMP
will always equal 32.
PIN DESCRIPTION
Pin 1 HON- Enable for driver operation,
high = active; low = inactive.
Pin 2 NC
Pin 3 Oscillator clock input
Pin 4 V
SS
- Power supply common, connect to
ground.
Pin 5 Coil - Coil input, connect coil from V
DD
to Pin 3.
Pin 6 Lamp- Lamp driver output1, connect to
EL lamp.
Pin 7 Lamp- Lamp driver output2, connect to
EL lamp.
Pin 8 V
DD
- Positive supply.
SP4412A Schematic
Q
Q
V
BATTERY
or V
DD
HON
V
DD
FF1
FF2
EL Lamp
6
V
DD
3
Coil
4
5
EL1
EL2
7
8
2
V
SS
30 mH at 125
1
Clock
Divider
Chain
External
Clock
NC
f
COIL
f
LAMP
f
LAMP
1
2
3
4
8
7
6
5
SP4412A
CN
SP4412ADS/12
SP4412ACN Electroluminescent Lamp Driver
Copyright 2000 Sipex Corporation
4
Typical SP4412ACN Application Circuit
The external clock should have a 50% duty
cycle and range from V
DD
-1V to ground. The
maximum external clock frequency is 128 kHz.
The coil is an external component connected
from V
BATTERY
to pin 5 of the SP4412A. Energy
is developed in the coil according to the equation
E
L
=1/2LI
2
where the current I is defined as
I=(V
BATTERY
-IR-V
OL
)/R
T
. In order to maximize
the energy produced by the coil, V
BATTERY
should
represent the largest voltage in the system (up to
a maximum of 3.6 v); V
BATTERY
= 3.0 VDC with
a 35mH/125
coil is a typical example. It is not
necessary that V
DD
=V
BATTERY
. The coil operation
is a function of the core material and winding
used -- performance variances may be noticeable
from different coil suppliers even though the
values are the same. The Sipex SP4412A is
final tested using a 35 mH/135 ohm coil. For
suggested coil sources see page 8.
The f
COIL
signal controls a switch that connects
the end of the coil at pin 5 to ground or to open
circuit. The f
COIL
signal is a 94% duty cycle
square wave, switching at 1/4 the oscillator
frequency, (for a 32 kHz oscillator f
COIL
is 8
kHz). During the time when the f
COIL
signal is
high, the coil is connected from V
BATTERY
to
ground and a charged magnetic field is created
in the coil. During the low part of f
COIL
, the
ground connection is switched open, the field
collapses, and the energy in the inductor is forced
to flow toward the high voltage H-bridge
switches. f
COIL
will send 16 of these charge
pulses to the lamp, each pulse increases the
voltage drop across the lamp in discrete steps. As
the voltage potential approaches its maximum,
the steps become shorter (see figure 1 on page 7).
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
LAMP
signal which is the oscillator frequency divided
by 128. For a 32kHz oscillator, f
LAMP
= 250Hz.
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 16 voltage steps
from ground to 80V (typical) on pins 6 and 7
which are 180 degrees out of phase with each
other (see figure 3 on page 7). A differential view
of the outputs is shown in figure 4 on page 7
.
ELECTROLUMINESCENT TECHNOLOGY
What is electroluminescence?
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 cannot be
implemented in most hand held equipment. Sipex
now offers low power single chip driver circuits
specifically designed to drive small to medium
sized electroluminescent panels. All that is
required is an external inductor and an external
clock signal.
LAMP
Coil
32-64 Khz
3 VDC
HON
Clk
V
SS
V
DD
Lamp
Lamp
Coil
1
3
4
5
8
6
7
30 mH 125 ohm Coil
2
SP4412ADS/12
SP4412ACN Electroluminescent Lamp Driver
Copyright 2000 Sipex Corporation
5
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
current than LEDs or incandescent bulbs making
them ideal for battery powered products. Also,
EL lamps are able to evenly light an area without
creating "hot spots" in the display.
The amount of light emitted is a function of the
voltage applied to the lamp, the frequency at
which it is applied, the lamp material used and
its size, and lastly, the inductor used. There
are many variables which can be optimized
for specific applications. Sipex supplies
characterization charts to aid the designer
in selecting the optimum circuit configuration
(see page 6).
SP4412ADS/12
SP4412ACN Electroluminescent Lamp Driver
Copyright 2000 Sipex Corporation
6
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.
FtL. vs Lamp Sizes for various Coils
lamp Sizes in sq. in.
Footlamberts (FtL)
0
1
2
3
4
5
6
0 . 5
0 . 7 5
1
1 . 5
2
25 mH 138
@ 3.0vdc
25 mH 138
@ 2.2vdc
15 mH 70
@ 3.0vdc
15 mH 70
@ 2.20vdc
20 mH 70
@ 3.0vdc
(CTC)
20 mH 70
@ 2.2vdc
(CTC)
29 mH 62
@ 3.0 vdc
( S k 1 2 1 )
29 mH 62
@ 2.2vdc
(Sk 121)
Lamp Sizes (sq. in.)
Brightness (FtL)
Brightness vs. Lamp Size as a function of coil inductance and impedance
25mH 138
@ 3.0 VDC
25mH 138
@ 2.2 VDC
15mH 70
@ 3.0 VDC
15mH 70
@ 2.20 VDC
29mH 62
@ 3.0 VDC
(SK121)
29mH 62
@ 2.2 VDC
(SK121)
20mH 70
@ 3.0 VDC
(CTC)
25mH 70
@ 2.2 VDC
(CTC)
SP4412ADS/12
SP4412ACN Electroluminescent Lamp Driver
Copyright 2000 Sipex Corporation
7
16 coil pulses per half cycle; 94% duty cycle.
EL1 Output
-EL2 Output
V
PEAK
=80V (typical)
EL1 output; 16 charge steps per half cycle
EL1 Output
-EL2 Output
V
PP
=160V
(typical)
Differential representation EL
12
.
Figure 1. EL output voltage in discrete steps at EL1 output
Figure 2. Voltage pulses released from the coil to the EL driver circuitry
Figure 3. EL voltage waveforms from the EL1 and EL2 outputs
Figure 4. EL differential output waveform of the EL1 and EL2 outputs
SP4412ADS/12
SP4412ACN Electroluminescent Lamp Driver
Copyright 2000 Sipex Corporation
8
EL Lamp manufacturers
Leading Edge Ind. Inc.
11578 Encore Circle
Minnetonka, MN 55343
Phone 1-800-845-6992
Midori Mark Ltd.
1-5 Komagata 2-Chome
Taita-Ku 111-0043 Japan
Phone: 81-03-3848-2011
Luminescent Systems inc. (LSI)
4 Lucent Drive
Lebanon, NH. 03766
Phone: (603) 643-7766
Fax: (603) 643-5947
EL polarizers/transflector
manufacturers
Nitto Denko
Yoshi Shinozuka
56 Nicholson Lane
San Jose, CA. 432-5480
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 (516)-223-7500
Fax (516)-868-2371
CTC Coils LTD (HK)
Flat L-M 14 Fl, Haribest Ind'l Bldg.
45-47 Au Pul Wan Street
Fo Tan Shatin. N.T., Hong Kong
Phone: 85 2695 4889
Fax: 85 2695 1842
Contact: Alfred Wong cc Marine Au
Inductance: 20 mH
10%
Resistance: 65 Ohms Max
Model Number: CH5070AS-203K-006
Sipex No. S51208-M-1021-Sipex
2.5
6.5 Max
9.0 Max
25
2.0
(All dimensions in mm)
Sankyo Shoji Co. (HK)
RM 28, 9/il Thriving Ind. Centre
Tsuen Wan, N.T.
Hong Kong
Phone: 8522 414 9268
Fax: 8522 413 6040
Contact: Mr. K.M. Chang
Inductance: 29mH
20 %
Resistance: 62 Ohms
10% @ 25C
Part Number SK-121
1.5
3.3
0.2
8.1
0.2
11.0
0.2
(All Dimensions in mm)
Sankyo Shoji Co. (HK)
RM 28, 9/il Thriving Ind. Centre
Tsuen Wan, N.T.
Hong Kong
Phone: 8522 414 9268
Fax: 8522 413 6040
Contact: Mr. K.M. Chang
Inductance: 65mH
15mH
Resistance: 270 Ohms
15% @ 25C
Part Number SK-80
0.8
2.4
5.6
(All Dimensions in mm)
3.6
Max.
7.0
0.5
6.0
0.3
3.3
0.3
6.8
0.3
HITACHI METALS Ltd.
Kishimoto Bldg.
2-1, Marunouchi 2-Chome,
Chiyoda-Ku, Tokyo Japan
Phone: 3-3284-4936
Fax: 3-3287-1945
Mr. Noboru Abe
Spec.-
9 mH
30% 42 ohm (Max)
Model: MD 735L902B
(All Dimensions in mm)
Singapore
Mr Stan kaiko,
Mr. Hiroshi Kai
Ph: 65-222-3077
Fax: 65-222-5232
Hong Kong
Mr Mori Ota
Ph: 852-2724-4183
Fax: 852-2311-2095
San Jose, CA
Mr. Kent Oda
Ph: 1-800-309-1803
Fx: 408 436-9601
Mark Technology: North American stocking distributor for Sankyo and CTC
Phone: 905-891-0165 FAX: 905-891-8534.
NEC Corporation
Yumi Saskai
7-1, Shiba 5 Chome, Minato-ku,
Tokyo 108-01, Japan
Phone: (03) 3798-9572
Fax: (03) 3798-6134
Seiko Precision
Shuzo Abe
1-1, Taihei 4-Chome,
Sumida-ku, Tokyo, 139 Japan
Phone: (03) 5610-7089
Fax: (03) 5610-7177
Gunze Electronics
2113 Wells Branch Parkway
Austin, TX 78728
Phone: (512) 752-1299
Fax: (512) 252-1181
SP4412ADS/12
SP4412ACN Electroluminescent Lamp Driver
Copyright 2000 Sipex Corporation
9
P
W
1
0.013
0.005
SP4412ACU
0.0256
BSC
0.118
0.002
0.020
2
0.020
0.116
0.004
0.034
0.002
0.040
0.002
0.004
0.002
0.118
0.002
0.118
0.004
0.037
Ref
0.0215
0.006
3.0
3
R .003
12.0
4
0.006
0.006
0.006
0.006
0.008
0 - 6
0.012
0.003
0.01
12.0
4
0.16
0.003
0.0965
0.003
0.116
0.004
1
0.228/0.244
0.150/0.157
0.189/0.197
0.014/0.019
0.050 BSC
0.053/0.069
SP4412ACN
Minimum qty per reel
Standard qty per reel
Maximum qty per reel
500
2500
3000
95 SP4412ACN per tube, no minimum quantity
NSOIC-8 13" reels: P=8mm, W=12mm
SOIC-8 13" reels: P=8mm, W=12mm
8-pin NSOIC
All package dimensions in inches
50 SP4412ACU per tube
8-pin
SOIC
SP4412ADS/12
SP4412ACN Electroluminescent Lamp Driver
Copyright 2000 Sipex Corporation
10
ORDERING INFORMATION
Model
Temperature Range
Package Type
SP4412ACN . ........................................... 0C to +70C ........................................... 8-Pin NSOIC
SP4412ACU ............................................. 0C to +70C ........................................... 8-Pin
SOIC
SP4412ACX ............................................. 0C to +70C .......................................................... Die
Please consult the factory for pricing and availability on a Tape-On-Reel option.
Corporation
SIGNAL PROCESSING EXCELLENCE
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 hereing; neither does it convey any license under its patent rights nor the rights of others.
Sipex Corporation
Headquarters and
Sales Office
22 Linnell Circle
Billerica, MA 01821
TEL: (978) 667-8700
FAX: (978) 670-9001
e-mail: sales@sipex.com
Sales Office
233 South Hillview Drive
Milpitas, CA 95035
TEL: (408) 934-7500
FAX: (408) 935-7600
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