Datasheet SP4415 Datasheet (Sipex)

SP4415DS/06 SP4415 Electroluminescent Lamp Driver © Copyright 1996 Sipex Corporation

1

■ 2.2 V- 3.6 V Battery Operation

■ 50 nA Maximum Standby Current

■ Four Level Selectable Output

■ High Voltage Output 140VPP Typical

■ High Impedance Clock Signal

Conditioner

APPLICATIONS

■ Watches

■ Pagers

■ Backlit LCD Displays

SP4415

DESCRIPTION

The SP4415 is a single chip DC-AC converter ideally suited for driving electroluminescent
panels to four intensity levels. The SP4415 is capable of converting DC input voltages as low
as 2.2V into any of four AC voltage levels which can be set via external switch. A high
impedance clock input and signal conditioner allows users to connect crystal oscillators
directly to the CLK input without interfering with existing system timing, no buffering of the
crystal oscillator is necessary. The SP4415 requires only one external inductor and is offered
in an 8-pin NSOIC package. For delivery in die form, please consult the factory.

SP4415 Block Diagram

SIGNAL PROCESSING EXCELLENCE

Electroluminescent Lamp Driver

with Selectable Level Outputs

No Connect

V

DD

Level Select

V

SS

COIL

EL2

EL1

SP4415

8
7

4

3

2

1

5

6

CLK

查询SP4415供应商

SP4415DS/06 SP4415 Electroluminescent Lamp Driver © Copyright 1996 Sipex Corporation

2

SPECIFICATIONS

T= 25°C; VDD = 3.0V; Lamp Capacitance = 2000pF; Coil = 30 mH at 125 Ohms; Osc = 32,768Hz (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.

VDD...................................................................................................7.0 V

Input Voltages/Currents

Level Select (pin 1).......................................-0.5V to (VDD+0.5V)

EN (pin3)............................................................................60mA

Lamp Outputs...............................................................................250V

PP

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

Power Dissipation Per Package

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

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

SP4415DS/06 SP4415 Electroluminescent Lamp Driver © Copyright 1996 Sipex Corporation

3

THEORY OF OPERATION

The SP4415 is made up of three basic circuit
elements, a clock signal conditioner, a divider
chain, and a switched H-bridge network. The clock
signal conditioner circuit allows users to directly
connect a crystal oscillator output to the SP4415;
no buffering is necessary. The clock input features
high impedance (50 MΩ), low capacitance (2.5pF)
and 200mV sensitivity. The external clock should
range from (VDD-1V) to ground. The SP4415 is
optimized for 32,768Hz clock signals and is allowed
to vary from 20 kHz to 60kHz.

The externally supplied clock signal provides the
circuit with a clock source used to control the
charge and discharge phases for the coil and lamp.
The suggested oscillator frequency is 32,768Hz .
This clock frequency is internally divided to create
two internal control signals, f

COIL

and f

LAMP

. For
example a 32,768Hz signal will be divided to
provide an 8,192Hz 75% duty cycle output to drive
the coil and a 256Hz 50% duty cycle output to
drive the lamp. Although the oscillator frequency
can be varied to optimize the lamp output, the ratio
of f

COIL

to f

LAMP

will always equal 32.

PIN DESCRIPTION

Pin 1 – NC - Float this pin..
Pin 2 – VSS - Ground connection
Pin 3 – Coil - Coil input, connect coil from V

DD

to Pin 5.
Pin 4 – Lamp2- EL voltage output, connect

directly to EL lamp.
Pin 5 – Lamp1- EL voltage output, connect

directly to EL lamp.
Pin 6 – VDD - Power supply for driver, connect to

system VDD.
Pin 7 – Level Select - Selects the number of

inductor drive pulses.
Pin 8 – Clk - Clock input for charge and

discharge cycles.

SP4415 Schematic

CLK

V

BATTERY

SCR1

SCR2

f

COIL

EL Lamp

Coil

2

3

EL1 EL2

4

8

V

ss

Level Select

V

DD

5

7

PULSE COUNT

DECODER

HON LEVEL

DECODER

PULSE COUNT

SELECTOR

2 BIT

COUNTER

9 BIT COUNTER Q

6

7 BIT COUNTER

CLR

Q

35mH/125 ohms

f

LAMP

f

LAMP

1
2
3
4

8
7
6
5

SP4415

SP4415DS/06 SP4415 Electroluminescent Lamp Driver © Copyright 1996 Sipex Corporation

4

Typical SP4415CN Application Circuit

1

V

SS

Coil
Lamp

V

DD

Lamp

Level
Select

CLK

32-64KHz

From crystal oscillator

Pushbutton level select

EL Lamp

3 VDC

Coil

35mH/125Ω coil

NC

The EL outputs can be enabled by driving the
Level Select pin (pin 7) high.

Four intensity levels can be set via the Level
Select pin (pin 7). The intensity levels correspond
with the number of coil pulses per bridge half
cycle. The full output is represented by 16 coil
pulses, levels 3, 2, 1 have 12, 9, and 7 coil pulses.
The coil pulses transfer energy to the EL lamp;
the more pulses per cycle, the brighter the lamp.

In order to set a level, the Level Select pin should
be driven high, then driven low (or released) and
within the next one second, the Level Select pin
should be again driven high; this sequence will
increment the level selection until the highest
level (level 4) is reached. The next sequence will
force the output back to the lowest intensity level,
level 1. The Level Select pin is equipped with a
debounce circuit such that momentary (≤15 mS)
opens of the input will not result in changes to the
output level.

The coil is an external component connected from
V

BATTERY

to pin 3 of the SP4415. Energy is

developed in the coil according to the equation
EL=1/2LI2 where the current I is defined as
I=(V

BATTERY

-IR-VOL)/RT. 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 6.0 v ); V

BATTERY

= 3.0 VDC with a

35mH/125Ω coil is a typical example. It is not
necessary that VDD=V

BATTERY

. The majority of the

supply current is dissipated in the coil (10mA
typical). The SP4415 itself requires less than 1mA
(700µA typical). Coils are also 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 SP4415 is final tested using a 35mH/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 3 to ground or to open circuit.
The f

COIL

signal is a 75% duty cycle square wave,
switching at 1/4 the oscillator frequency. For a
32,768 Hz oscillator f

COIL

is 8,192Hz. 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).

SP4415DS/06 SP4415 Electroluminescent Lamp Driver © Copyright 1996 Sipex Corporation

5

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 32,768 Hz oscillator, f

LAMP

=256 Hz.

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

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 one external inductor.

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.

SP4415DS/06 SP4415 Electroluminescent Lamp Driver © Copyright 1996 Sipex Corporation

6

Level 4, 16 Coil pulses
100% of V

OUT

Level 3, 12 Coil pulses
85% of V

OUT

Level 2, 9 Coil pulses
80% of V

OUT

Level 1, 7 Coil pulses
75% of V

OUT

SP4415 Level Select Control

Full

Level 4

Level 3

Level 2

Level1

OFF

Enabled

Disabled

1 sec

Previously set level

Output Intensity

Level Select

SP4415DS/06 SP4415 Electroluminescent Lamp Driver © Copyright 1996 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

VPP=160V
(typical)

Differential Representation EL

12

.

Figure 1.

Figure 2.

Figure 3.

Figure 4.

SP4415DS/06 SP4415 Electroluminescent Lamp Driver © Copyright 1996 Sipex Corporation

8

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)
101 Etna Road
Lebanon, NH. 03766-9004
Phone: [phone]
Fax: [phone]

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 [phone]
Fax [phone]

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: [phone]
Fax: [phone]
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: [phone]
Fax: [phone]
Contact: Mr. K.M. Chang
Inductance: 29mH ±20 %
Resistance: 62 Ohms ±10% @ 25˚C
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: [phone]
Fax: [phone]
Contact: Mr. K.M. Chang
Inductance: 65mH ±15mH
Resistance: 270 Ohms ±15% @ 25˚C
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: [phone]
Fax: [phone]
Mr. Noboru Abe
Spec.­9 mH ±30% 42 ohm (Max)
Model: MD 735L902B

(All Dimensions in mm)

Singapore
Mr Stan kaiko,
Mr. Hiroshi Kai
Phone: [phone]
Fax: [phone]

Hong Kong
Mr Mori Ota
Phone: [phone]
Fax: [phone]

San Jose, CA
Mr. Kent Oda
Ph: 408 436-9505
Fx: 408 436-9601

Mark Technology: North American stocking distributor for Sankyo and CTC
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]

SP4415DS/06 SP4415 Electroluminescent Lamp Driver © Copyright 1996 Sipex Corporation

9

P

W

1

0.228/0.2440.150/0.157

0.189/0.197

0.014/0.019

0.050 BSC

0.053/0.069

SP4415ACN

Minimum qty per reel Standard qty per reel Maximum qty per reel

500 2500 3000

95 SP4415ACN per tube.

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

All package dimensions in inches

8-pin NSOIC

SP4415DS/06 SP4415 Electroluminescent Lamp Driver © Copyright 1996 Sipex Corporation

10

ORDERING INFORMATION

Model Temperature Range Package Type

SP4415CN . ............................................. 0˚C to +70˚C ...........................................8-Pin NSOIC

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 herein; 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: [phone]
FAX: [phone]
e-mail: [e-mail]

Sales Office

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

Far East:
JAPAN:

Nippon Sipex Corporation
Yahagi No. 2 Building
3-5-3 Uchikanda, Chiyoda-ku
Tokyo 101
TEL: [phone]
FAX: [phone]

European Sales Offices:
ENGLAND:

Sipex Corporation
2 Linden House
Turk Street
Alton Hampshire GU34 IAN
England
TEL: [phone]
FAX: [phone]
e-mail: [e-mail]

GERMANY:

Sipex GmbH
Gautinger Strasse 10
82319 Starnberg
TEL: [phone]
FAX: [phone]
e-mail: [e-mail]

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