Datasheet SP4480EN, SP4480EY, SP4480NEB Datasheet (Sipex Corporation)

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Page 1

SP4480

Dual Electroluminscent Lamp Driver

■ Backlights Keypad & LCD With A Single El Driver

■ A Single External IC Drives Dual EL Lamps Simultaneously Or Independently

■ A Single Coil Drives Both EL Lamp

■ A Single Resistor Controls the Operating

Frequency

■ DC-to-AC Inverter Produces Up To 200V

■ Low Current Standby Mode Draws Less

■ +2.2V to +6.0V Battery Operation

DESCRIPTION

The SP4480 provides a designer with two electroluminescent lamp drivers for backlighting solutions. The EL lamp outputs operate in opposite phase so he SP4480 device can be easily implemented into applications driving two EL lamps simultaneously or driving double-sided, multi-color EL lamps. The integration of a dual EL lamp driver in a cost-effective single IC reduces component count and board space requirements. The SP4480 is ideal for portable applications such as cellular phones, pagers, PDAs, medical equipment, and other designs with liquid crystal displays, keypads, and backlit readouts. The SP4480 operates from a +2.2V to +6.0V source. The device features a low power standby mode which draws less than 1µA (maximum). The frequency of the internal oscillator is set with a single external resistor. A single inductor is required to generate the high voltage AC outputs to drive the EL lamps. All input pins are ESD protected with internal diodes to VDD and VSS.

P-P

Than 1µA

OSC

1 2 3 4

5 6 7

SP4480

ELEN1

ELEN2

R no connect no connect

no connect

14 13 12 11 10

V EL2

EL1 EL3 EL4 CAP COIL8

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

Input Voltages, Logic.....................-0.3V to (V

Lamp Outputs...................................................220V

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

+0.3V)

P-P

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

Power Dissipation Per Package 14-pin SOIC

(derate 8.33mW/˚C above +70˚C)....................700mW

14-pin TSSOP

(derate 9.96mW/˚C above +70˚C)....................800mW

SPECIFICATIONS

VDD = +3.0V, L = 470µH, C

elcyCytuDlioC09%

I,tnerruClioC

LAMP

= 8nF, R

= 402kΩ, and T

OSC

= 25˚C unless otherwise noted.

AMB

RETEMARAP.NIM.PYT.XAMSTINUSNOITIDNOC

V,egatloVylppuS

I,tnerruCylppuS

I,tnerruCnwodtuhS

DSI=LIOCI+DD

V,egatloVtupnINELE

NELE

WOL

HGIH57.2

ecnatsiseRtupnI

2NELEdna1NELE

2.20.30.6V 24 AmL

0.3

1MΩ

EVIRDROTCUDNI

f,ycneuqerFlioC

LIOC

I,tnerruClioCkaeP

LIOC-KP

7507

9306Am 47001AmngisedybdeetnarauG

TUPTUOPMALLE

f,ycneuqerFpmaLLE

PMAL

V,egatloVtuptuOkaePotkaeP

053

054055

213 831

KP-KP

031

071

STORAGE CONSIDERATIONS

Storage in a low humidity environment is preferred. Large high density plastic packages are moisture sensitive and should be stored in Dry Vapor Barrier Bags. Prior to usage, the parts should remain bagged and stored below 40°C and 60%RH. If the parts are removed from the bag, they should be used within 48 hours or stored in an environment at or below 20%RH. If the above conditions cannot be followed, the parts should be baked for four hours at 125°C in order remove moisture prior to soldering. Sipex ships product in Dry Vapor Barrier Bags with a humidity indicator card and desiccant pack. The humidity indicator should be below 30%RH.

The information furnished by Sipex has been carefully reviewed for accuracy and reliability. Its application or use, however, is solely the responsibility of the user. No responsibility of the use of this information become part of the terms and conditions of any subsequent sales agreement with Sipex. Specifications are subject to change without no responsibility for any infringement of patents or other rights of third parties which may result from its use. No license or proprietary rights are granted by implication or otherwise under any patent or patent rights of Sipex Corporation.

074= µH

LIOC

µA

52.0V

zHk

075

T T

V0=

NELE

52+=oC

BMA

04-=

BMA

52+=oC

BMA

04-=

BMA

52+=oC

BMA

04-=

BMA

58+otC

Page 3

PINOUT

OSC

1 2 3 4

5 6 7

ELEN1

ELEN2

R no connect no connect

no connect

PIN ASSIGNMENTS

Pin 1 — ELEN1 — Electroluminescent Lamp

Enable 1. When driven HIGH, this input pin enables the EL driver outputs for EL1 and EL2. This pin has an internal pulldown resistor.

Pin 2 — ELEN2 — Electroluminescent Lamp

Enable 2. When driven HIGH, this input pin enables the EL driver outputs for EL3 and EL4. This pin has an internal pulldown resistor.

Pin 3 — R

ing a resistor between V

— Oscillator Resistor. Connect-

OSC

and this pin sets

the frequency of the internal clock.

Pin 4 — No Connect.

V EL2

EL1 EL3

SP4480

11 10

EL4 CAP COIL8

Pin 9 — CAP — Integrating Capacitor. An

integrating capacitor connected from this pin to ground filters out any coil switching spikes or ripple present in the output waveform to the EL lamps. Connecting a fast recovery diode from COIL to CAP increases the light output of the EL lamp.

Pin 10 — EL4 — Electroluminescent Lamp

Output 4. This is a high voltage lamp driver output pin paired with EL3 to drive the EL2 lamp.

Pin 11 — EL3 — Electroluminescent Lamp

Output 3. This is a high voltage lamp driver output pin paired with EL4 to drive the EL2 lamp.

Pin 5 — No connect.

Pin 12 — EL1 — Electroluminescent Lamp

Output 1. This is a high voltage lamp driver

Pin 6 — No connect.

output pin paired with EL2 to drive the EL1 lamp.

Pin 7 — VSS — Power Supply Ground. Connect

to the lowest circuit potential, typically ground.

Pin 8 — COIL — Coil. The inductor for the

boost converter is connected from V

BATT

this pin.

Pin 13 — EL2 — Electroluminescent Lamp

Output 2. This is a high voltage lamp driver output pin paired with EL1 to drive the EL1 lamp.

Pin 14 — VDD — Positive Power Supply. This

pin should be bypassed with a 0.1µF capacitor.

Page 4

SP4480

1.8kΩ

COIL

CAP

EL1

EL2

SCR2

SCR3

EL3

SCR4

EL4

OSC

ELEN2

ELEN1

OSC

FF7

LAMP2

COIL

LAMP1

LAMP2

SCR1

Figure 1: Internal Block Diagram of SP4480

DESCRIPTION

high voltage AC signal is applied across it. It

behaves primarily as a capacitive load. Long The SP4480 Dual Electroluminescent Lamp Driver is a low-cost, low voltage device ideal for the replacement of LED backlighting designs in keypads, handsets, PDAs and other portable designs. The EL lamp driver outputs operate in opposite phase so the SP4480 device can be easily implemented into applications driving two EL lamps simultaneously or double-sided EL lamps. Having a dual lamp driver solution on a single IC makes available precious printed circuit board real estate for designers additional circuitry.

periods of DC voltage applied to the material

tend to reduce its lifetime. With these condi-

tions in mind, the ideal signal to drive an EL

lamp is a high voltage sine wave. Traditional

approaches to achieve this type of waveform

include discrete circuits incorporating a trans-

former, transistors and several resistors and

capacitors. This approach is large and bulky and

cannot be implemented in most handheld equip-

ment. Sipex offers low power single chip driver

circuits specifically designed to drive small to

medium sized electroluminescent panels. Sipex

EL drivers provide a differential AC voltage The SP4480 contains a DC-AC inverter that can produce an AC output of 180V a +2.2V to +6.0V input voltage. An internal

(typical) from

P-P

block diagram of SP4480 can be found in Figure

without a DC offset to maximize EL lamp life-

time. The only additional components required

for the EL driver circuitry are an inductor, resis-

tor and capacitor.

Electroluminescent Technology

Electroluminescent backlighting is ideal when

used with LCD's keypads or other backlit dis-

An EL lamp consists of a thin layer of phosphorous material sandwiched between two strips of plastic which emits light (flouresces) when a high voltage AC signal is applied across it. It

plays. EL lamps uniformly light an area without

creating any undesirable "hot spots" in the dis-

play. Also, an EL lamp consumes less power

that LED's or incandescent bulbs in similar

Page 5

VBATT

ELEN1

ELEN2

470µH

SP4480

VDD

ROSC

402kΩ

0.1µF

Figure 2: Typical Application Circuit of the SP4480

1nF

* optional device

lighting situations. These features make EL ideal for attractive, battery powered products.

ROSC

EL1

EL Lamp

13 11

EL2

1012

EL Lamp

As the voltage approaches its maximum, the steps become smaller. (see figure 4). The brightness of the EL lamp output is directly

THEORY OF OPERATION

related to energy recovery in the boost converter. There are many variations among coils

Coil Switch

The SP4480 has an inductor-based boost converter to generate the high voltage used to drive the EL lamp. Energy is stored in the inductor according to the equation EL = 1/2 (LI Ipk = (tON) (V lator controls the coil switch. During the time

BATT

- V

) /L. An internal oscil-

CEsat

) where

the coil switch is on, the coil is connected between VDD and the saturation voltage of the coil switch and a magnetic field develops in the coil. When the coil switch turns off, the switch opens, the magnetic field collapses and the voltage across the coil rises. The internal diode forward biases when the coil voltage rises above the H-Bridge voltage and the energy enters the EL lamp. Each pulse increases the voltage across the lamp in discrete steps.

such as magnetic core differences, winding differences and parasitic capacitances. For suggested coil suppliers refer to page 10.

Oscillator

The internal oscillator generates a high frequency clock used by the boost converter and HBridge. An external resistor from VDD to ROSC sets the oscillator frequency. Typically a 402kΩ resistor sets the frequency to 57kHz. The high frequency clock directly controls the coil switch. This high frequency clock is divided by 128 to generate a low frequency clock which controls the EL H-Bridge and sets the EL lamp frequency. The oscillator has low sensitivity to temperature and supply voltage variations, increasing the performance of the EL

COIL

CAP

VSS

EL4EL3

1N4148

INT

1800pF

Page 6

driver over the operating parameters.

Dual H-Bridge

The H-Bridge consists of two SCR structures and two NPN transistors that control how the lamp is charged. Setting ELEN1 to HIGH activates the EL1 and EL2 outputs. Setting ELEN2 to HIGH activates EL3 and EL4 outputs. The EL driver illuminates the lamp by applying the high voltage supply of the boost converter to the lamp terminals through the HBridge and then switching the terminals polarity between the high voltage supply and ground at a constant frequency. This applies an AC voltage to the lamp that is twice the peak output voltage of the boost driver. An AC voltage greater than the 40V across the terminals of the lamp is typically necessary to adequately illuminate the EL lamp.

Both EL drivers may be operated simultaneously but with decreased light output from the EL panels.

DESIGN CONSIDERATIONS Inductor Selection

If limiting peak current draw from the power supply is important, small coil values (<1mH) may need a higher oscillator frequency. Inductor current ramps faster in a lower inductance coil than a higher inductance coil for a given coil switch on time period, resulting in higher peak coil currents.

Lamp Effects

EL lamp parameters vary between manufactur-

ers. Series DC resistance, lighting efficiency

and lamp capacitance per area differ the most

overall. Larger lamps require more energy to

illuminate. Lowering the oscillator frequency

allows more energy to be stored in the coil

during each coil switch cycle and increases

lamp brightness. The oscillator frequency can

be lowered to a point where the lamp brightness

then begins to drop because the lamp frequency

must be above a critical frequency (approx.

100Hz) to light. Lamp color is affected by the

switching frequency of the EL driver. Green EL

lamps will emit a more blue light as EL lamp

frequency increases.

Noise Decoupling on Logic Inputs

If ELEN1 or ELEN2 are connected to traces

susceptible to noise, it may be necessary to

connect bypass capacitors of approximately 10nF

between ELEN1 and VSS and ELEN2 and VSS.

If these inputs are driven by a microprocessor

which provides a low impedance HIGH and

LOW signal, then noise bypassing may not be

necessary.

Increasing Light Output

EL lamp light output can be improved by connecting a fast recovery diode from the COIL pin to the CAP pin. The internal diode is bypassed resulting in an increase in light output at the EL lamp. We suggest a fast recovery diode such as the industry standard 1N4148.

It is important to observe the saturation current rating of a coil. When this current is exceeded, the coil is incapable of storing any more energy and then ceases to act as an inductor. Instead, the coil behaves according to its series DC resistance. Since small coils (<1mH) have inherently low series DC resistance, the current can peak dramatically through a small coil during saturation. This situation results in wasted energy not stored in the magnetics of the coil but expressed as heating which could lead to failure of the coil.

Generally, selecting a coil with lower series DC resistance will result in a system with higher efficiency and lamp brightness.

The optimal value of C on the lamp parameters and coil value. Lower C

values can decrease average supply current

INT

but higher C ness. This is best determined by experimenta-

values can increase lamp bright-

INT

will vary depending

INT

tion. A rule of thumb is larger coils (1mH) are paired with a smaller C coils (470µH) are paired with a larger C (1800pF).

(680pF) and smaller

INT

Changing the EL lamp Output Voltage Waveform

Designers can alter the sawtooth output voltage waveform to the EL lamp. Increasing the capacitance of the integration capacitor, C integrate the sawtooth waveform making it ap-

INT

, will

pear more like a square wave.

Page 7

Printed Circuit Board Layout Suggestions

The EL driver's high-frequency operation makes PCB layout important for minimizing electrical noise. Keep the IC's GND pin and the ground leads of C1 and C Also keep the connections to the COIL pin as

less than 0.2in (5mm) apart.

INT

short as possible. To maximize output power and efficiency and minimize output ripple voltage, use a ground plane and solder the IC's VSS pin directly to the ground plane.

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, the frequency at which is applied, the lamp material, the lamp size, and the inductor used. Sipex supplies characterization charts to aid the designer in selecting the optimum circuit configuration.

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 provide retrofits to nonbacklit products for a thorough electrical and cosmetic evaluation. Please contact your local Sipex sales Representative or the Sipex factory directly to initiate this valuable service.

Page 8

+3V

ELEN1

500kΩ

1nF

ELEN2

N/C

Figure 3: Test Circuit Digram of SP4480

+3V

OSC

SP4480

EL2

EL1

EL3

EL4

CAP

COIL

7.3nF, 2.5in

1N4148

EL1

EL2

0.1µF

1000pF

+3V

820µH*

*DC Resistance 13Ω*

Figure 4: Typical EL Lamp Voltage Waveform

Page 9

PERFORMANCE CHARACTERISTICS

100

CAP,pk

) (V

k p , P A

), V

A (m

D D

200 400 600 800 1000

(kΩ)

OSC

Figure 1

140

120

100

) (V

k p ,

CAP,pk

A C

), V

A (m

Lumi.

2.0 3.0 4.0 5.0 6.0

(V)

Figure 2

14.0

12.0

10.0

8.0

6.0

4.0

2.0

0.0

)

(ft-L e c n a

in m

u L

600

550

Freq.

500

450

) z

400

. (H q

350

F p

300

m a L

250

Lumi.

200

150

100

200 400 600 800 1000

OSC

Figure 3

100

CAP,pk

Lumi.

) (V

k p , P A

), V

A (m

D D

400 500 600 700 800 900 1000

Inductor Value (µH)

Figure 4

(kΩ)

10.0

9.0

8.0

7.0

6.0

5.0

4.0

3.0

2.0

1.0

0.0

6.0

5.5

5.0

)

4.5

(ft-L

4.0

e c n

3.5

a in

3.0

m u L

2.5

2.0

1.5

1.0

)

(ft-L e c n a

in m

u L

Page 10

Coil Manufacturers

Hitachi Metals Material Trading Division 2101 S. Arlington Heights Road, Suite 116 Arlington Heights, IL 60005-4142 Phone: 1-800-777-8343 Ext. 12 (847) 364-7200 Ext. 12 Fax: (847) 364-7279

Hitachi Metals Ltd. Europe Immernannstrasse 14-16, 40210 Dusseldorf, Germany Contact: Gary Loos Phone: 49-211-16009-0 Fax: 49-211-16009-29

Hitachi Metals Ltd. Kishimoto Bldg. 2-1, Marunouchi 2-chome, Chiyoda-Ku, Tokyo, Japan Contact: Mr. Noboru Abe Phone: 3-3284-4936 Fax: 3-3287-1945

Hitachi Metals Ltd. Singapore 78 Shenton Way #12-01, Singapore 079120 Contact: Mr. Stan Kaiko Phone: 222-8077 Fax: 222-5232

Hitachi Metals Ltd. Hong Kong Room 1107, 11/F., West Wing, Tsim Sha. Tsui Center 66 Mody Road,Tsimshatsui East, Kowloon, Hong Kong Phone: 2724-4188 Fax: 2311-2095

Murata 2200 Lake Park Drive, Smyrna Georgia 30080 U.S.A. Phone: (770) 436-1300 Fax: (770) 436-3030

Murata European Holbeinstrasse 21-23, 90441 Numberg, Postfachanschrift 90015 Phone: 011-4991166870 Fax: 011-49116687225

Murata Taiwan Electronics 225 Chung-Chin Road, Taichung, Taiwan, R.O.C. Phone: 011 88642914151 Fax: 011 88644252929

Murata Electronics Singapore 200 Yishun Ave. 7, Singapore 2776, Republic of Singapore Phone: 011 657584233 Fax: 011 657536181

Murata Hong Kong Room 709-712 Miramar Tower, 1 Kimberly Road, Tsimshatsui, Kowloon, Hong Kong Phone: 011-85223763898 Fax: 011-85223755655

Panasonic. 6550 Katella Ave Cypress, CA 90630-5102 Phone: (714) 373-7366 Fax: (714) 373-7323

Sumida Electric Co., LTD. 5999, New Wilke Road, Suite #110 Rolling Meadows, IL,60008 U.S.A. Phone: (847) 956-0666 Fax: (847) 956-0702

Sumida Electric Co., LTD. 4-8, Kanamachi 2-Chrome, Katsushika-ku, Tokyo 125 Japan Phone: 03-3607-5111 Fax: 03-3607-5144

Sumida Electric Co., LTD. Block 15, 996, Bendemeer Road #04-05 to 06, Singapore 339944 Republic of Singapore Phone: 2963388 Fax: 2963390

Sumida Electric Co., LTD. 14 Floor, Eastern Center, 1065 King's Road, Quarry Bay, Hong Kong Phone: 28806688

Fax: 25659600

Polarizers/transflector Mnfg.

Nitto Denko Yoshi Shinozuka Bayside Business Park 48500 Fremont, CA. 94538 Phone: 510 445 5400 Fax: 510 445-5480

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

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) 101 Etna Road Lebanon, NH. 03766-9004 Phone: (603) 448-3444 Fax: (603) 448-3452

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

Page 11

PACKAGE: PLASTIC NARROW

SMALL OUTLINE (NSOIC)

DIMENSIONS

in. (mm)

Minimum/Maximum

14–PIN

0.053/0.069

(1.346/1.748)

0.004/0.010

(0.102/0.249)

0.014/0.018

(0.360/0.460)

0.337/0.344

(8.552/8.748)

0.150/0.157

(3.802/3.988)

0.050 BSC

(1.270 BSC)

0.228/0.244

(5.801/6.198)

0.016/0.050

(0.406/1.270)

0°/8°

(0°/8°)

Page 12

P ACKA GE: PLASTIC THIN SMALL

OUTLINE (TSSOP)

Minimum/Maximum

DIMENSIONS

in inches (mm)

14–PIN

- /0.043 (- /1.10)

0.002/0.006 (0.05/0.15)

0.007/0.012 (0.19/0.30)

0.193/0.201 (4.90/5.10)

0.169/0.177 (4.30/4.50)

0.026 BSC (0.65 BSC)

0.126 BSC (3.20 BSC)

0.020/0.030 (0.50/0.75)

0°/8°

Page 13

ORDERING INFORMATION

Model Temperature Range Package Type

SP4480EN .............................................. -40˚C to +85˚C ....................................... 14-Pin NSOIC

SP4480EY .............................................. -40˚C to +85˚C ...................................... 14-Pin TSSOP

SP4480NEB ........................................................................................................ Evaluation Board

Corporation

SIGNAL PROCESSING EXCELLENCE

Sipex Corporation

Headquarters and Main Offices:

233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 935-7600 FAX: (408) 934-7500

22 Linnell Circle Billerica, MA 01821 TEL: (978) 667-8700 FAX: (978) 670-9001

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.

Datasheet SP4480EN, SP4480EY, SP4480NEB Datasheet (Sipex Corporation)

Specifications and Main Features

Frequently Asked Questions

User Manual