SP4428 [SIPEX]
Electroluminescent Lamp Driver High Drive Capability for Low Voltage Applications; 电致发光灯驱动器的高驱动能力低电压应用
| 型号： | SP4428 |
| 厂家： | 
SIPEX CORPORATION |
| 描述： | Electroluminescent Lamp Driver High Drive Capability for Low Voltage Applications |
| 文件： | 总11页 (文件大小：110K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
®
SP4428
Electroluminescent Lamp Driver
High Drive Capability for Low Voltage Applications
■ Low Power +1.1V to +1.7V Single
Cell Operation
■ Low-Cost EL Driver Ideal for Backlighting
■ DC-to-AC Inverter Generates High
Voltage AC to Drive EL Lamps
■ Externally Adjustable Oscillator
■ Low Current Standby Mode
APPLICATIONS
■ Pagers
■ Watches
■ Backlit LCD Displays
DESCRIPTION
The SP4428 is a high voltage output DC-AC converter that can operate from a single 1.5 VDC
powersupply. TheSP4428 iscapableofsupplying200VPP (typical), makingitidealfordriving
electroluminescent lamps. The device features 1µA (typical) standby current, for use in low
power portable products. One external inductor is required to generate the high voltage
charge, and one external capacitor is used to produce a clock signal that generates the coil
and lamp frequencies. The SP4428 is ideal for PDAs, pagers, and other low power portable
applications using LCDs in dim or low light environments. The SP4428 is offered in an 8-pin
narrow SOIC. For delivery in die form, please consult the factory.
HON
1
2
3
8
7
6
5
COSC
VSS
VDD
EL1
EL2
SP4428
COIL
D1 4
Block Diagram
SP4428DS/16
SP4428 Electroluminescent Lamp Driver
© Copyright 2000 Sipex Corporation
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.
ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation of the device at
theseratingsoranyotherabovethoseindicatedintheoperationsections
ofthespecificationsbelowisnotimplied. Exposuretoabsolutemaximum
rating conditions for extended periods of time may affect reliability.
TA= +25˚C unless otherwise noted
VDD............................................................................................................5V
Input Voltages/Currents
HON (pin1).........................................-0.5V to (VDD+0.5V)
COIL (pin3)............................................................100mA
Lamp Outputs.............................................................................230VPP
Storage Temperature....................................................-65˚C to +150˚C
Power Dissipation Per Package
8-pin NSOIC (derate 6.14mW/oC above +70oC).................................500mW
SPECIFICATIONS
(T= 25°C; VDD = 1.5V; Lamp Capacitance = 4.7nF; Coil = 470µH at 4.9 Ohms; COSC = 180pF unless otherwise noted) CINT = 1800pF
PARAMETER
Supply Voltage, VDD
MIN.
TYP.
MAX.
UNITS
CONDITIONS
1.1
1.5
1.7
V
Supply Current, ICOIL+IDD
35
45
50
80
VDD=1.1V, VHON=1.1V
DD=1.5V, VHON=1.5V
mA
V
V
Coil Voltage, VCOIL
VDD
1.7
HON Input Voltage, VHON
LOW: EL off
-0.25
0
0.25V
V
HIGH: EL on
VDD-0.25
VDD
VDD+0.25
µA
µA
HON Current, EL on
Shutdown Current, ISD=ICOIL+IDD
INDUCTOR DRIVE
3
15
10
internal pulldown, VHON=VDD=1.5V
VHON=0V
0.5
Coil Frequency, fCOIL
Coil Duty Cycle
28.8
90
kHz
%
Peak Coil Current, IPK-COIL
EL LAMP OUTPUT
100
mA
Guaranteed by design.
TAMB=+25OC, VDD=1.1V
EL Lamp Frequency, fLAMP
150
300
150
500
550
750
450
Hz
T
AMB=+25OC, VDD=1.5V
TAMB=-40OC to +85OC, VDD=1.5V
Peak to Peak Output Voltage
90
120
120
160
VDD=1.1V
VDD=1.5V
VPP
SP4428DS/16
SP4428 Electroluminescent Lamp Driver
© Copyright 2000 Sipex Corporation
2
THEORY OF OPERATION
PIN DESCRIPTION
The SP4428 is made up of three basic circuit
elements, an oscillator, coil, driver and switched
H-bridge network. The oscillator provides the
devicewithanon-chipclocksourceusedtocontrol
the charge and discharge phases for the coil and
lamp. An external capacitor connected between
pins 1 and VSS allows the user to vary the oscillator
frequency. For a given choice of coil inductance
there will be an optimum COSC Capacitor value that
gives the maximum light output in a given lamp.
1
2
3
4
8
7
6
5
Pin 1 – COSC- Connect CAP from VSS to Pin 1 to
set Oscillator frequency.
The suggested oscillator frequency is 28.8kHz
(COSC=180pF). The oscillator output is internally
divided to create the control signal fLAMP
.
Pin 2 – VSS- Power supply common, connect to
ground.
The oscillator output is internally divided down
by 6 flip flops, a 28.8kHz signal will be divided
into 6 frequency levels; 14.4kHz, 7.2kHz, 3.6kHz,
1.8kHz, 900Hz, and 450Hz. The oscillator output
(28.8kHz) is used to drive the coil (see figure 2 on
page 7) and the sixth flip flop output (300Hz) is
used to drive the lamp. Although the oscillator
frequency can be varied to optimize the lamp
output, the ratio of fCOIL/fLAMP will always equal 64.
Pin 3 – Coil- Coil input, connect coil from
VBATTERY to Pin 3.
Pin 4 – D1- Diode cathode connection.
Pin 5 – EL2- Lamp driver output1, connect to
EL lamp.
Pin 6 – EL1- Lamp driver output2, connect to
EL lamp.
The coil is an external component connected from
VBATTERY to pin 3 of the SP4428. Energy is
developed in the coil according to the equation
EL=1/2LI2 where the current I is defined as
I=(VBATTERY-IR-VOL)/RT. In order to maximize the
Pin 7 – VDD- Power supply for driver, connect to
system VDD.
Pin 8 – HON- Enable for driver operation,
high = active; low = inactive.
VBATTERY
470µH/4.9Ω
Optional
1,800pF
VDD
IN4148
3
4
7
8
.1µF
VDD
HON
Coil
D1
1MΩ
OSC
COSC
1
SCR2
SCR1
fCOIL
Cap1
180pF
fLAMP
Q
FF1
FF6
Q
fLAMP
VSS
EL1
5
EL2
2
6
EL Lamp
SP4428 Schematic
SP4428DS/16
SP4428 Electroluminescent Lamp Driver
© Copyright 2000 Sipex Corporation
3
energy produced by the coil VBATTERY should
represent the largest voltage in the system (up to
the maximum tolerance of the coil) and the coil
should have low resistance; VBATTERY= 1.5 VDC
with a 470µH/4.9Ω coil are typical. The majority
of the current goes through the coil and typically
less than 1mA is required for VDD of the SP4428.
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 a voltage step
fromgroundto80V(typical)onpins5and6which
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. If Line
Noise is of concern it is advisable to add a
decoupling cap at VDD.
V
canrangefrom1.5Vto1.7V;itisnotnecessary
thDaDt VDD=VBATTERY. Coils are also a function of the
core material and winding used -- performance
variances may be noticeable from different coil
suppliers. The Sipex SP4428 is final tested using
a 470µH/4.9Ω coil from Sumida. For suggested
coil sources see page 9.
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,
andseveralresistorsandcapacitors. Thisapproach
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 if all that is required is
one external inductor fast recovery diode and two
capacitors.
The f
signal controls a switch that connects the
end oCfOtIhLe coil at pin 3 to ground or to open circuit.
ThefCOIL signalisa90%dutycyclesignalswitching
at the oscillator frequency. During the time when
the fCOIL signal is high, the coil is connected from
V
to ground and a charged magnetic field is
crBeAaTtTeEdRYin the coil. During the low part of fCOIL , the
ground connection is switched open, the field
collapses and the energy in the inductor is forced
to flow toward the lamp. fCOIL will send 32 of these
charge pulses every half cycle (see figure 2
on page 7) 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 smaller (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 fLAMP
signal which is the oscillator frequency divided by
64. For a 20kHz oscillator, fLAMP=300Hz.
Pager
Application
0.1µF
1
HON
COSC
180pF
+
-
5 FtL
1.5 Volt
Battery
VSS
Coil
D1
VDD
EL1
EL2
LAMP
Fast
Recovery
Diode
Optional
1800pF CAP
1.5 SQ. IN.
470µH
4.9 Ohms
Typical SP4428 Application Circuit
SP4428DS/16
SP4428 Electroluminescent Lamp Driver
© Copyright 2000 Sipex Corporation
4
Electroluminescentbacklightingisidealwhenused
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 than LEDs
or 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
voltageappliedtothelamp, thefrequencyatwhich
it is applied, the lamp material used and its
size. There are many variables which can be
optimizedforspecificapplications.Sipexsupplies
characterization charts to aid the designer in
selecting the optimum circuit configuration
(see page 6 and 7).
SP4428DS/16
SP4428 Electroluminescent Lamp Driver
© Copyright 2000 Sipex Corporation
5
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.
VDD=VCOIL=1.5V; coil = 470µH/4ohm; COSC = 180pf; CINT = 1800pf; CLOAD = 4.7nF
Peak voltage vs.Temperature
Total IDD vs.Temperature
VDD = 1.5V
70
60
50
40
30
20
10
0
200
150
100
50
0
-40
0
25
70
85
-40
0
25
70
85
O
O
Temperature ( C)
Temperature ( C)
Lamp Frequency vs.Temperature
500
450
400
350
300
250
200
150
100
50
0
-40
0
25
70
85
O
Temperature ( C)
SP4428DS/16
SP4428 Electroluminescent Lamp Driver
© Copyright 2000 Sipex Corporation
6
VPEAK=80V (typical)
EL1 output; 32 charge steps per half cycle
Figure 1. EL output voltage in discrete steps at EL1 output
16 coil pulses per half cycle; 94% duty cycle.
Figure 2. Voltage pulses released from the coil to the EL driver circuitry
EL1 Output
-EL2 Output
Figure 3. EL voltage waveforms from the EL1 and EL2 outputs
EL1 Output
VPP=160V
(typical)
-EL2 Output
Differential representation EL12
.
Figure 4. EL differential output waveform of the EL1 and EL2 outputs
SP4428DS/16
SP4428 Electroluminescent Lamp Driver
© Copyright 2000 Sipex Corporation
7
BONDING DIAGRAM
X
PAD PIN
X
Y
HON
VDD
8
7
6
5
4
3
2
1
-822.5
205.0
796.0
870.5
870.5
785.5
175.5
-848.0
393.5
418.5
349.5
19.5
Y
VDD
HON
EL1
EL1
EL2
CAP
COIL
VSS
-189.5
-389.5
-420.5
-106.0
EL2
CAP
COSC
COSC
VSS COIL
NOTES:
1. Dimensions are in Microns unless otherwise noted.
2. Bonding pads are 125 X 125 typical.
3. Outside dimensions are maximum, including scribe area.
4. Die thickness is 380 ± 25 microns.
5. Pad center coordinates are relative to die center.
6. Die size (step size): 81 X 46 mils
Figure 5. Bonding Diagram
SP4428DS/16
SP4428 Electroluminescent Lamp Driver
© Copyright 2000 Sipex Corporation
8
Coil Manufacturers
New Coils
.155
.260
Max
6.60
Coilcraft USA
Ph: (847) 639-6400
Fax: (847) 639-1469
Coilcraft Taiwan
Ph: 886/2/264-3646
Fax: 886/2/270-0294
Coilcraft Hong Kong
Ph: 852 770-9428
Fax: 852 770-0729
Dia
.115
Max
.175
Max
Coilcraft Europe
Ph: 44 01236 730595
Fax: 44 01236 730627
Coil Craft Singapore
Ph: 65 296-6933
Fax: 465 296-4463 #382
Part No. DO1608C-474
470µH, 3.60 ohm
(All Dimensions in mm)
5.0 ±0.3
5.0 ±0.3
muRata USA
Ph: (770) 436-1300
Fax: (770) 436-3030
muRata Taiwan Electronics
Ph: 011 88642914151
Fax: 011 88644252929
muRata Hong Kong
Ph: 011-85223763898
Fax: 011 852237555655
muRata Europe
Ph: 011-4991166870
Fax: 011-49116687225
muRata Electronics
Singapore
Ph: 011 657584233
Fax: 011 657536181
Part No. LQN4N471K04
470µH, 11.5 ohm
5.7 ±0.3
(All Dimensions in mm)
KOA Speer Electronics, Inc.
Ph: 814-362-5536
Fax: 814-362-8883
4.5
±
Part No. LPC4045TE471K
470µH, 4.55 ohm
4.0 ± 0.2
4.5 Max
(All Dimensions in mm)
Sumida Electric Co., LTD. Sumida Electric Co., LTD.
7.3 ±0.2
USA
Singapore
Ph: (847) 956-0666
Fax: (847) 956-0702
Ph: 2963388
Fax: 2963390
7.3
4.5
Max
Sumida Electric Co., LTD. Sumida Electric Co., LTD.
Japan
Hong Kong
Part No. CDRH74-471MC
470µH, 3.01 ohm
Ph: 03-3607-5111
Fax: 03-3607-5144
Ph: 28806688
Fax: 25659600
(All Dimensions in mm)
4.4 Max
Toko America Inc. USA
Ph: (847) 297-0070
Fax: (847) 699-7864
Toko Inc. Japan
Ph: 03 3727 1161
Fax: 03 3727 1176
Toko Inc. Hong Kong
Ph: 2342-8131
Fax: 2341-9570
Toko Inc. Europe
Ph: (0211) 680090
Fax: (0211) 679-9567
Toko Inc. Singapore
Ph: (255) 4000
Fax: (250) 8134
2.75 Max
Part No. 667MA471N
470µH, 1.90 ohm
4.4 Max
(All Dimensions in mm)
EL polarizers/transflector
manufacturers
NEC Corporation
Yumi Saskai
7-1, Shiba 5 Chome, Minato-ku,
Tokyo 108-01, Japan
Phone: (03) 3798-9572
Fax: (03) 3798-6134
EL Lamp manufacturers
Leading Edge Ind. Inc.
11578 Encore Circle
Minnetonka, MN 55343
Phone 1-800-845-6992
Nitto Denko
Yoshi Shinozuka
Bayside Business Park 48500
Fremont, CA 94538
Phone: 510 445-5400
Fax: 510 445-5480
Seiko Precision
Shuzo Abe
1-1, Taihei 4-Chome,
Sumida-ku, Tokyo, 139 Japan
Phone: (03) 5610-7089
Fax: (03) 5610-7177
Midori Mark Ltd.
1-5 Komagata 2-Chome
Taita-Ku 111-0043 Japan
Phone: 81-03-3848-2011
Top Polarizer- NPF F1205DU
Bottom - NPF F4225
or (F4205) P3 w/transflector
Luminescent Systems inc. (LSI)
101 Etna Road
Lebanon, NH. 03766-9004
Phone: (603) 448-3444
Fax: (603) 448-33452
Transflector Material
Astra Products
Mark Bogin
Gunze Electronics
2113 Wells Branch Parkway
Austin, TX 78728
Phone: (512) 752-1299
Fax: (512) 252-1181
P.O. Box 479
Baldwin, NJ 11510
Phone (516)-223-7500
Fax (516)-868-2371
SP4428DS/16
SP4428 Electroluminescent Lamp Driver
© Copyright 2000 Sipex Corporation
9
All package dimensions in inches
8-pin NSOIC
0.189/0.197
SP4428
0.150/0.157
0.228/0.244
0.053/0.069
0.014/0.019
0.050 BSC
1
95 NSOIC SP4428 per tube, no minimum quantity
P
W
NSOIC-8 13" reels: P=8mm, W=12mm
Pkg.
CN
Minimum qty per reel
Standard qty per reel
Maximum qty per reel
3000
500
2500
SP4428DS/16
SP4428 Electroluminescent Lamp Driver
© Copyright 2000 Sipex Corporation
10
ORDERING INFORMATION
Temperature Range
Model
Package Type
SP4428CN . ............................................. 0˚C to +70˚C ........................................... 8-Pin NSOIC
SP4428NEB ............................................................................................ NSOIC Evaluation Board
Please consult the factory for pricing and availability on a Tape-On-Reel option.
Co rp o ra tio n
SIGNAL PROCESSING EXCELLENCE
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
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.
SP4428DS/16
SP4428 Electroluminescent Lamp Driver
© Copyright 2000 Sipex Corporation
11
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