® SP4412A Electroluminescent Lamp Driver ■ 2.2 V- 3.6 V Battery Operation ■ 50 nA Maximum Standby Current (10 nA typical) ■ High Voltage Output Typical 160 VPP ■ External Oscillator Required ■ Enable Control Pin APPLICATIONS ■ Watches ■ Pagers ■ Backlit LCD Displays 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 VPP 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 µSOIC package. For delivery in die form, please consult the factory. HON 1 No Connect 2 Osc Input VSS 3 6 EL1 4 5 COIL 8 VDD SP4412A 7 EL2 SP4412A Block Diagram SP4412ADS/12 SP4412ACN Electroluminescent Lamp Driver 1 © Copyright 2000 Sipex Corporation ABSOLUTE MAXIMUM RATINGS 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. 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..................................................................................................5.0 V Input Voltages/Currents HON (pin 1).........................................-0.5V to (VDD+0.5V) COIL (pin 3)..............................................................60mA Lamp Outputs...............................................................................250VPP Storage Temperature.....................................................-65˚C to +150˚C Power Dissipation Per Package 8-pin NSOIC (derate 6.14mWoC above +70oC)...................................500mW 8-pin µSOIC (derate 4.85mWoC above +70oC)....................................390mW SPECIFICATIONS T= 25°C; VDD = 3.0V; Lamp Capacitance = 2000pF; Coil = 30 mH at 125 Ohms; External Oscillator = 32768Hz (unless otherwise noted). PARAMETER MIN. TYP. MAX. UNITS 2.2 3.0 3.6 V 5 2.0 mA 3.6 V Supply Voltage, VDD Supply Current, ICOIL+IDD VDD Coil Voltage, VCOIL HON Input Voltage, VHON LOW: EL off HIGH: EL on CONDITIONS VHON=VDD=3V -0.25 VDD-0.25 0 VDD 0.25V VDD+0.25 V 1 10 100 µA 10 50 nA VHON=0V 8192 Hz Input Oscillator=32768Hz 75 % HON Current, EL on Shutdown Current, ISD=ICOIL+IDD INDUCTOR DRIVE Coil Frequency, fCOIL=fLAMPx32 Coil Duty Cycle 60 mA Guaranteed by design. 256 Hz Input Oscillator=32768Hz 160 VPP Peak Coil Current, IPK-COIL EL LAMP OUTPUT EL Lamp Frequency, fLAMP Peak to Peak Output Voltage 120 BONDING DIAGRAM 1143 (45) Measured from center of Pads. Clk. HON Y VDD VSS (0,0) X 1397 (55) SP4412ADS/12 X 218.5 418.5 418.5 -178.0 95.5 -416.0 Y 555.5 555.5 339.5 -555.5 -555.5 -555.5 -416.0 219.0 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. Coil Lamp 2 PIN CLK HON VDD EL2 EL1 COIL VSS Lamp 1 SP4412ACN Electroluminescent Lamp Driver 2 © Copyright 2000 Sipex Corporation THEORY OF OPERATION PIN DESCRIPTION SP4412ACN 1 2 3 4 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. 8 7 6 5 Pin 1 – HON- Enable for driver operation, high = active; low = inactive. The suggested oscillator frequency is 32,768Hz. This clock frequency is internally divided to create two internal control signals, fCOIL and fLAMP. 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 fCOIL/ fLAMP will always equal 32. Pin 2 – NC Pin 3 – Oscillator clock input Pin 4 – VSS - Power supply common, connect to ground. Pin 5 – Coil - Coil input, connect coil from VDD 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 – VDD - Positive supply. VDD VBATTERY or VDD 30 mH at 125Ω 8 1 External Clock 5 HON VDD fCOIL Clock Divider Chain 3 Coil fLAMP Q FF1 2 NC FF2 Q fLAMP VSS EL1 4 6 EL2 7 EL Lamp SP4412A Schematic SP4412ADS/12 SP4412ACN Electroluminescent Lamp Driver 3 © Copyright 2000 Sipex Corporation 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 128. For a 32kHz oscillator, fLAMP= 250Hz. The external clock should have a 50% duty cycle and range from VDD-1V to ground. The maximum external clock frequency is 128 kHz. The coil is an external component connected from VBATTERY to pin 5 of the SP4412A. 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 energy produced by the coil, VBATTERY should represent the largest voltage in the system (up to a maximum of 3.6 v); VBATTERY= 3.0 VDC with a 35mH/125Ω coil is a typical example. It is not necessary that VDD=VBATTERY. 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. 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. The fCOIL signal controls a switch that connects the end of the coil at pin 5 to ground or to open circuit. The fCOIL signal is a 94% duty cycle square wave, switching at 1/4 the oscillator frequency, (for a 32 kHz oscillator fCOIL is 8 kHz). During the time when the fCOIL signal is high, the coil is connected from VBATTERY to ground and a charged magnetic field is created in 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 high voltage H-bridge switches. fCOIL 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). 1 3 VDC HON 2 VDD 8 Lamp 7 3 Clk Lamp 6 4 VSS Coil 5 Coil 32-64 Khz LAMP 30 mH 125 ohm Coil Typical SP4412ACN Application Circuit SP4412ADS/12 SP4412ACN Electroluminescent Lamp Driver 4 © Copyright 2000 Sipex Corporation 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 5 © Copyright 2000 Sipex Corporation 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 Brightness Lamp Sizes forSize various Coils vs. Lamp as a function of coil inductance and impedance 6 25mH 3.03.0vdc VDC 25 mH 138Ω 138 Ω@@ 25mH 2.22.2vdc VDC 25 mH 138Ω 138 Ω@@ 5 Brightness (FtL) Footlamberts (FtL) 15mH 3.03.0vdc VDC 15 mH 70Ω 70 Ω@@ 4 15mH 2.20 VDC 15 mH 70Ω 70 Ω@@ 2.20vdc 20mH VDC 20 mH 70Ω 70 Ω@@3.0 3.0vdc (CTC) (CTC) 3 25mH 2.22.2vdc VDC 20 mH70Ω 70 Ω@@ (CTC) (CTC) 2 29mH 29 mH 62Ω 62 Ω@@3.0 3.0VDC vdc (SK121) (Sk121) 1 29mH VDC 29 mH62Ω 62 Ω@@2.2 2.2vdc (SK121) (Sk 121) 0 0.5 0.75 1 1.5 2 lamp Sizes Sizes(sq. in in.) sq. in. Lamp SP4412ADS/12 SP4412ACN Electroluminescent Lamp Driver 6 © Copyright 2000 Sipex Corporation VPEAK=80V (typical) EL1 output; 16 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 SP4412ADS/12 SP4412ACN Electroluminescent Lamp Driver 7 © Copyright 2000 Sipex Corporation 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 Singapore Mr Stan kaiko, Mr. Hiroshi Kai Ph: 65-222-3077 Fax: 65-222-5232 San Jose, CA Mr. Kent Oda Ph: 1-800-309-1803 Fx: 408 436-9601 6.8 ±0.3 7.0 ±0.5 Hong Kong Mr Mori Ota Ph: 852-2724-4183 Fax: 852-2311-2095 3.3 ±0.3 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% @ 25˚C Part Number SK-121 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% @ 25˚C Part Number SK-80 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 6.0 ±0.3 (All Dimensions in mm) 8.1 ±0.2 11.0 ±0.2 1.5 (All Dimensions in mm) 3.3 ±0.2 3.6 5.6 Max. 0.8 2.4 (All Dimensions in mm) 25 ± 2.0 2.5 6.5 Max 9.0 Max (All dimensions in mm) Mark Technology: North American stocking distributor for Sankyo and CTC Phone: 905-891-0165 FAX: 905-891-8534. 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 SP4412ADS/12 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 SP4412ACN Electroluminescent Lamp Driver 8 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 © Copyright 2000 Sipex Corporation All package dimensions in inches 8-pin µSOIC 8-pin NSOIC 0.0256 BSC 12.0˚ ±4˚ 0.012 ±0.003 0.0965 ±0.003 SP4412ACU SP4412ACN 0.228/0.244 0.053/0.069 0˚ - 6˚ 0.006 ±0.006 0.006 ±0.006 R .003 0.118 ±0.002 0.189/0.197 0.150/0.157 0.008 0.16 ±0.003 12.0˚ ±4˚ 0.01 0.020 0.020 1 3.0˚ ±3˚ 0.0215 ±0.006 0.037 Ref 2 0.014/0.019 0.050 BSC 0.116 ±0.004 1 0.034 ±0.002 0.116 ±0.004 0.040 ±0.002 0.013 ±0.005 0.118 ±0.002 95 SP4412ACN per tube, no minimum quantity 0.118 ±0.004 0.004 ±0.002 50 SP4412ACU per tube P W NSOIC-8 13" reels: P=8mm, W=12mm µSOIC-8 13" reels: P=8mm, W=12mm Minimum qty per reel 500 SP4412ADS/12 Standard qty per reel 2500 SP4412ACN Electroluminescent Lamp Driver 9 Maximum qty per reel 3000 © Copyright 2000 Sipex Corporation ORDERING INFORMATION Model Temperature Range Package Type SP4412ACN . ........................................... 0˚C to +70˚C ........................................... 8-Pin NSOIC SP4412ACU ............................................. 0˚C to +70˚C ........................................... 8-Pin µSOIC SP4412ACX ............................................. 0˚C to +70˚C .......................................................... Die 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: (978) 667-8700 FAX: (978) 670-9001 e-mail: [email protected] 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 hereing; neither does it convey any license under its patent rights nor the rights of others. SP4412ADS/12 SP4412ACN Electroluminescent Lamp Driver 10 © Copyright 2000 Sipex Corporation