Data Sheet D306A Electroluminescent Lamp Driver IC General Description The Durel® D306A is a high-power IC inverter intended for driving EL lamps as large as 180 cm2. The D306A IC is equipped with many control functions, including: waveshapingTM programmability for minimizing audible noise, and features that allow for component cost-savings, precision control of frequencies, and stability of lamp color over wide temperature extremes. D3 06 A SOIC - 16 with Heat Slug Features • • • • • Applications 2.0 - 12.0 VDC Battery Operation High AC Voltage Output to 400Vpp Very Low Standby Current Flexible Wave-shaping Capability SOIC-16 Narrow Body with Heat Slug • • • • PDA Large Area LCD with EL Lamp Backlight Signage Backlighting Graphics Display Lighting Sample Application Circuit BAS21 EL Lamp 200V 2.2nF (200V) ON OFF 0 5.0V + - 1 Va NC 16 2 NC L 15 14 3 Cs NC 4 Vb GND 13 5 E 6 Rf 12 Vcc CLF 11 7 NC NC 10 8 NC 3.3mH Coilcraft D03316 + - Vbat = 12.0V 100pF 10nF 100k CHF 9 D306A 220pF Sample Output Waveform Typical Output Brightness = 24.5 fL (83.9 cd/m2) Lamp Frequency = 448 Hz Logic Supply Current = 25 mA Power Supply Current = 42 mA Vout = 330 Vpp Load = 6 in2 (38.7 cm2) Durel® Green EL 1 Absolute Maximum Ratings Parameter Supply Voltage Operating Range Withstand Range Logic Drive Voltage Operating Range Withstand Range Enable Voltage Vout Operating Temperature Symbol Minimum Vbat 2.0 -0.5 12 16 V E = Vcc E = GND Vcc 2 -0.5 -0.5 5 6 Vcc + 0.5 410 85 125 40 150 V E = Vcc E = GND E Va - Vb Ta* Tj -40 θja Average Thermal Resistance Storage Temperature Ts -55 Maximum Unit V Vpp °C °C °C/W °C Comments E = Vcc Ambient Junction Junction to Ambient *At a given ambient temperature, the maximum power rating can be calculated with the following equation: Tj = P(θja)+Ta. Note: The above are stress ratings only. Functional operation of the device at these ratings or any other above those indicated in the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. Physical Data PIN # NAME 1 16 2 15 3 14 4 13 5 12 6 11 7 10 8 9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Va NC Cs Vb E Vcc NC NC CHF NC CLF Rf GND NC L NC FUNCTION AC voltage output to EL lamp No connect High voltage storage capacitor to input AC voltage output to EL lamp System enable: Wave-shaping resistor control Logic drive voltage No connect No connect Capacitor input to high frequency oscillator No connect Capacitor input to low frequency oscillator Resistor input for frequency control Power ground No connect Inductor input No connect RECOMMENDED PAD LAYOUT b SOIC-16 with Heat Slug PAD LAYOUT a Min. mm. i c h d f g e a b c d e f g h i 4.267 0.609 5.791 2 Typical in. 0.168 0.024 0.228 mm. Max. in. 1.270 8.890 0.050 0.350 0.711 0.028 0.545 8.748 0.830 3.437 0.021 0.344 0.033 0.135 mm. 4.673 0.812 6.197 in. 0.184 0.032 0.244 600 600 500 500 400 400 LF (Hz) LF (Hz) Typical Performance Characteristics Using Standard Test Circuit 300 200 300 200 100 100 0 0 5 6 7 8 9 -60 10 11 12 13 14 15 16 17 -40 -20 300 Output Voltage Vout Max 0 7 8 300 200 Output Voltage Vout Max 100 0 -60 9 10 11 12 13 14 15 16 17 -40 -20 Output Voltage (Vrms) Output Voltage (Vrms) 100 50 0 9 50 0 -60 -40 20 40 60 80 100 Output Voltage (Vrms) vs. Ambient Temperature Avg Supply Current (mA) Avg Supply Current (mA) 0 Temperature ( C) 60 40 20 0 9 -20 o 80 8 100 100 100 7 80 150 10 11 12 13 14 15 16 17 Output Voltage (Vrms) vs. DC Supply Voltage 6 60 200 DC Input Voltage (Vbat) 5 40 Output Voltage (Vpp) vs. Ambient Temperature 150 8 20 Temperature ( C) 200 7 0 o Output Voltage (Vpp) vs. DC Supply Voltage 6 100 400 DC Input Voltage (Vbat) 5 80 500 Output Voltage (Vpp) Output Voltage (Vpp) 400 6 60 Output Frequency vs. Ambient Temperature 500 5 40 Temperature ( C) Output Frequency vs. DC Supply Voltage 100 20 o DC Input Voltage (Vbat) 200 0 10 11 12 13 14 15 16 17 100 80 60 40 20 0 -60 -40 -20 0 20 40 60 80 100 Temperature ( oC) DC Input Voltage (Vbat) Supply Current (Ibat) vs. Ambient Temperature Supply Current (Ibat) vs. DC Supply Voltage 3 Block Diagram of the Driver Circuitry Theory of Operation Electroluminescent (EL) lamps are essentially capacitors with one transparent electrode and a special phosphor material in the dielectric. When a strong AC voltage is applied across the EL lamp electrodes, the phosphor glows. The required AC voltage is typically not present in most systems and must be generated from a low voltage DC source. The D306A IC inverter drives the EL lamp by using a switching transistor to repeatedly charge an external inductor and discharge it to the high voltage capacitor Cs. The discharging causes the voltage at Cs to continually increase. The internal circuitry uses the H-bridge technology, using both electrodes to drive the EL lamp. One of the outputs, Va or Vb, is used to discharge Cs into the EL lamp during the first half of the low frequency (LF) cycle. By alternating the state of the H-bridge, the other output is used to charge the EL lamp during the second half of the LF cycle. The alternating states make it possible to achieve 400V peakto-peak across the EL lamp. The EL driving system is divided into several parts: on-chip logic control, on-chip high voltage output circuitry, on-chip discharge logic circuitry, and off-chip components. The on-chip logic controls the lamp operating frequency (LF) and the inductor switching frequency (HF). These signals are used to drive the high voltage output circuitry (H-bridge) by delivering the power from the inductor to the lamp. The integrated discharge logic circuitry uses a patented wave shaping technique for reducing audible noise from an EL lamp. Changing the Rd value changes the slope of the linear discharge as well as the shape of the waveform. The off-chip component selection provides a degree of flexibility to accommodate various lamp sizes, system voltages, and brightness levels. Typical D306A EL driving configurations for driving EL lamps in various applications are shown on the following page. The expected system outputs for the various circuit configurations are also shown with each respective figure. These examples are only guides for configuring the driver. Durel provides a D306A Designer's Kit, which includes a printed circuit evaluation board intended to aid you in developing an EL lamp driver configuration using the D306A that meets your requirements. A section on designing with the D306A is included in this datasheet to serve as a guide to help you select the appropriate external components to complete your D306A EL driver system. 4 Typical D306A EL Driver Configurations 5.0V PDA Display BAS21 Typical Output 470uH TDK SLF7032 Brightness = 22.0 fL (75.4 cd/m2) Lamp Frequency = 370 Hz Logic Supply Current = 25 mA Power Supply Current = 108 mA Vout = 380 Vpp Load = 5 in2 (32.2 cm2) Durel® Green EL PDA LCD EL Lamp 1 Va 2 NC 3 Cs NC 14 4 Vb GND 13 5 E 6 7 8 NC NC 16 L 15 5.0V 2.2nF (200V) ON OFF 5.0V Rf 12 Vcc CLF 11 NC NC 10 100pF 10 kOhm 8.2nF 100kOhm CHF 9 D306A 68pF 12.0 V Dual D306A for Sign Backlight Typical Output Brightness = 27.1 fL (92.8 cd/m2) Lamp Frequency = 525 Hz Logic Supply Current = 48 mA Power Supply Current = 212 mA Vout = 368 Vpp Load = 18.3 in2 (118 cm2) Durel® White EL White EL Lamp BAS21 BAS21 1.5mH Coilcraft D03316P 200V 1 2.2nF (200V) Va 2 NC 3 Cs 4 NC L 200V 1.5mH Coilcraft D03316P 16 2.2nF (200V) 15 GND 13 10 kOhm ON OFF 5.0V 5 Rf E NC 16 2 NC L 15 3 Cs NC 14 4 Vb GND 13 5 E Rf 12 6 Vcc CLF 11 7 NC NC 10 8 NC CHF 9 12 100kOhm 6 Vcc CLF 11 7 NC NC 10 8 Va 12.0V NC 14 Vb 1 6.8nF 100pF CHF 9 NC D306A D306A 220pF 5 3.6V Alternating Circuit* Typical Output EL Lamp 1 Typical Output EL Lamp 2 Brightness = 14 fL (48.0 cd/m ) Lamp Frequency = 300 Hz Logic Supply Current = 24 mA Power Supply Current = 74 mA Vout = 272 Vpp Load = 8 in2 (cm2) Durel® White EL Brightness = 14 fL (48.0 cd/m2) Lamp Frequency = 300 Hz Logic Supply Current = 24 mA Power Supply Current = 74 mA Vout = 272 Vpp Load = 8 in2 (cm2) Durel® White EL 2 8in2 EL Lamp 1 8in2 EL Lamp 2 BAS21 200V BAS21 200V .680mH Coilcraft D03316P 10nF (200V) 1 Va NC 16 1 Va NC 16 2 NC L 15 2 NC L 15 3 Cs NC 14 3 Cs NC 14 4 Vb GND 13 4 Vb GND 13 5 E Rf 12 5 E Rf 12 6 Vcc CLF 11 7 NC NC 10 8 NC CHF 9 6 Vcc 7 8 CLF 11 NC NC 10 NC CHF 9 10nF (200V) 3.6V 100kOhm 3.0V .680mH Coilcraft D03316P 100kOhm 100pF 3.0V 6.8nF D306A 100pF 6.8nF D306A 220pF 1N4148 3.6V 220pF 100kohm E1 10kohm 1N4148 100kohm 10kohm 2.2uF E2 CD4011 or equivalent *Note: Two separate backlight systems are alternately enabled using the same supply lines. 9.0V Large Signage Lamp BAS21 Typical Output Brightness = 4.90 fL (16.8 cd/m ) Lamp Frequency = 335 Hz Logic Supply Current = 24 mA Power Supply Current = 148 mA Vout = 224 Vpp Load = 30 in2 (193.5 cm2) Durel® Green EL 1.0mH Coilcraft D03316 2 Large Area EL Lamp 1 Va NC 16 2 NC L 15 3 Cs NC 14 4 Vb GND 13 5 E 6 12.0V 2.2nF (200V) 200V ON OFF 5.0V Rf 12 Vcc CLF 11 7 NC NC 10 8 NC 10nF CHF 9 D306A 6 100pF 10 kOhm 68pF 100kOhm Designing With D306A There are many variables which can be optimized to achieve the desired performance for specific applications. The luminance of the EL lamp is a function of the output voltage applied to the lamp by the IC, the frequency at which the voltage is applied, the lamp material properties, and the lamp size. Durel offers the following component selection aids to help the designer select the optimum circuit configuration. Inductor Frequency (kHz) 80 0 35 40 200 400 600 800 1000 45 CLF (nF) Luminance (fL) Figure 1: Typical Lamp Frequency vs. CLF Capacitor II. Inductor Switching Frequency (CHF) Selection 25 160 20 140 15 120 10 100 Luminance 5 80 Current Draw (mA) Lamp Frequency (Hz) 200 30 10 The inductor value has a large impact on the output brightness and current consumption of the driver. Figure 3 shows typical brightness and current draw of a D306A circuit with different inductor values. Please note that the DC resistance (DCR) and current rating of inductors with the same inductance value may vary with manufacturer and inductor type. Thus, inductors made by a different manufacturer may yield different outputs, but the trend of the different curves should be similar. This curve is intended to give the designer a relative scale from which to optimize specific applications. Absolute measurements may vary depending upon the type and brand of other external components selected. 400 25 20 III. Inductor (L) Selection 600 20 30 Figure 2: Typical Inductor Frequency vs.CHF Capacitor 800 15 40 CHF (pF) 1000 10 50 0 Selecting the appropriate value of capacitor (CLF) for the low frequency oscillator will set the output frequency of the D306A EL driver IC. Figure 1 graphically represents the effect of the CLF capacitor value on the oscillator frequency at Vbat = 13.5V, Vcc = 5.0V. 5 60 0 I. Lamp Frequency Capacitor (CLF) Selection 0 70 Current Selecting the appropriate value of capacitor (CHF) for the high frequency oscillator will set the inductor switching frequency of the D306A inverter. Figure 2 graphically represents the effect of the CHF capacitor value on the oscillator frequency at Vbat = 13.5V, Vcc = 5.0V. 0 60 0 1 2 3 4 5 6 7 8 9 10 Inductor Value (mH) Figure 3: Brightness and current vs. inductor value Conditions: Vcc = 5V, Vbat = 6.5V, 6.1 in2 (39.4 cm2) EL Lamp 7 IV. Wave-Shape Selection The D306A EL Driver uses a patented wave-shaping technique for reducing audible noise from an EL lamp. The slope of the discharge section of the output waveform may be adjusted by selecting a proper value for the wave-shape discharge resistor (Rd) in series with the E pin input. The optimal discharge level for an application depends on the lamp size, lamp brightness, and application conditions. To ensure that the D306A is configured optimally, various discharge levels should be evaluated. In many cases, lower discharge levels may result in lower audible noise from the EL lamp. The recommended typical value for Rd is 10 kΩ. V. Storage Capacitor (Cs) Selection The Cs capacitor is used to store the energy transferred from the inductor before discharging the energy to the EL lamp. Cs values can range from 1.5nF to 4.7nF and must have minimum 200V rating. In general, the Cs value does not have a large affect on the output of the device. The typical Cs capacitor recommendation is 2.2nF with 200V rating. VI. Rf and CRf Selection The combination of Rf and timing capacitors, CLF and CHF, determines the time constants for the low frequency oscillator and the high frequency oscillator, respectively. To simplify the tuning of the oscillator frequencies to the desired frequency range, a standard value is recommended for Rf = 100 kΩ. The CRf capacitor is used as a stabilizing capacitor to filter noise on the Rf line. A small 100pF capacitor is typical and sufficient value for CRf. VII. Fast Recovery Diode Energy stored by the coil is eventually forced through the external diode to power the switched H-bridge network. A fast recovery diode, such as BAS21, is recommended for this function for optimum operation. VIII. Printed Circuit Board Layout The high frequency operation and very high voltage output of the D306A makes printed circuit board layout important for minimizing electrical noise. Maintain the IC connections to the inductor as short as possible. Connect the GND of the device directly to the GND plane of the PCB. Keep the GND pin of the device and the ground leads of the Cs, CLF, and CHF less than 5mm apart. If using bypass capacitors to minimize ripple on the supply lines, keep the bypass caps as close as possible to the Vbat lead of the inductor and the Vcc pin. The higher than normal operating temperature of the D306A also requires additional ground heat planes on the printed circuit board layout. The D306A has a heat slug attached to the bottom of the packge to provide additional heat dissipation. It is recommended that the PCB incorporate a complimentary grounded heat plane to solder connect to the heat slug of the package. It is also recommended that no electrical traces, which can be adversely affected by the temperature transfer and the high voltage output, be laid out underneath the device. The temperture transfer, as well as high voltage output, may adversely affect these electrical traces. Recommended pad layout dimensions can be found on the last page of this datasheet. IX. Optional Zener Diodes The D306A EL driver circuit should be designed such that the output voltage of the device does not exceed the maximum rated value of 400Vpp. Operating the D306A above this rating can cause irreversible damage to the device. This condition is most likely in applications, such as in automotive instrument clusters, where the supply voltage (Vbat) is higher than 6.0V and can generate output voltage greater than 400Vpp. Extreme temperature change can also cause the output voltage to exceed the maximum rating, especially when the nominal operating voltage of the device is close to the maximum limit at room temperature. A zener diode connected in parallel to the Cs capacitor and ground of the D306A is recommended to limit the device output to less than 400Vpp. This component is optional and may be avoided in applications which are known to function only within safe operating conditions. 8 X. Split Voltage Supply A split supply voltage is recommended to drive the D306A. To operate the on-chip logic, a regulated voltage supply (Vcc) ranging from 2.0V to 6.5V is applied. To supply the D306A with the necessary power to drive an EL lamp, another supply voltage (Vbat) with higher current capability is applied to the inductor. The voltage range of Vbat is determined by the following conditions: user application, lamp size, inductor selection, and power limitations of the battery. An example of the split supply configuration is shown below. This example shows a regulated 5.0V applied to the Vcc pin, and a Vbat voltage that may range from 9.0V to 16.0V or regulated at 13.5V. The enable voltage is in the range of 3.0V to 5.0V. This is a typical setup used in automotive applications. BAS21 6.8mH Coilcraft D03316 Automotive EL Lamp 2.2nF (200V) 200V ON OFF 5.0V 1 Va NC 16 2 NC L 15 3 Cs NC 14 4 Vb GND 13 5 E 6 Rf 12 Vcc CLF 11 7 NC NC 10 8 NC 9.0V - 16.0V Battery or 13.5V Regulated 100pF 0 Ohm 10nF CHF 9 D306A 120pF 9 100kOhm D306A Design Ideas I. Controlling Output Frequency Using External Clock Signals External clock signals may be used to control the D306A oscillator frequencies instead of adding external passive components. When clocking signals provide both the inductor charging (HF) and lamp output (LF) oscillator frequencies to drive the D306A, the CLF, CHF, Rf, and CRf components are no longer required. A sample configuration demonstrating this cost-saving option is shown below. BAS21 EL Lamp 200V 2.2nF (200V) ON OFF 5.0V 1 Va NC 16 2 NC L 15 3 Cs NC 14 4 Vb GND 13 5 E 6 6.5V 10 kOhm Rf 12 Vcc CLF 11 7 NC NC 10 8 NC CHF 9 800 Hz 15% + duty 1.0V Min 0.2V Max 1.0V Min 0.2V Max D306A 32 kHz 10% + duty In this configuration, the lamp frequency is controlled by the signal applied to the CLF pin. An internal divider network in the IC divides the frequency of the LF input signal by two. Thus, to get a 400 Hz AC output waveform to drive the EL lamp, an 800 Hz square-wave input signal should be connected to the CLF pin. Input clocking frequencies may range from 400 Hz to 2000 Hz, with 10-20% positive duty cycle for optimum brightness. The amplitude of the clock signal typically ranges from 1.0V to Vcc. The high frequency oscillator that determines inductor charging frequency is controlled above by a digital AC signal into the CHF pin. The HF clock signal frequency may range from 20KHz - 35KHz, with 10-20% positive duty cycle for optimum lamp intensity. The amplitude of the clock signal typically ranges from 1.0V to Vcc. 10 II. Controlling EL Brightness through Clock Pulse Width Modulation (Option 1) Pulse width modulation of the external LF input signal may be used to regulate the brightness of the EL lamp. Figures 4, 5, and 6 below demonstrate examples of the D306A output waveform with pulse width modulation of the LF input signal. As the positive duty cycle of the LF input signal is increased from 10% to 100%, the charging period of the output waveform decreases, and the peak voltage of the output waveform also decreases towards zero output. Therefore, incremental dimming occurs as a result of the wave-shaping changes. This scheme may also be used inversely to regulate lamp brightness over the life of the battery or to compensate for lamp aging. Figure 7 shows a typical dimming curve with this technique. Operation at duty cycles lower than 10% is not recommended. Clocking frequency can range from 400 Hz to 2000 Hz. The maximum amplitude of the clock signal may range from 1.0V to Vcc. BAS21 EL Lamp ON OFF Va NC 16 2 NC L 15 3 Cs NC 14 4 Vb GND 13 5 E 6 Vcc 6.5V 2.2nF (200V) 200V 1 10 kOhm Rf 12 CLF 11 10 800 Hz 10% to 100% positive duty PWM 1.0V Min 5.0V 0.2V Max 7 NC NC 8 NC CHF 9 1.0V Min 0.2V Max D306A 32 kHz 10% positive duty Luminance (fL) Figure 6: LF Input Duty Cycle = +75% 20 150 16 120 12 90 8 60 Luminance Current 4 30 0 0 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% LF Clock Input Duty Cycle Figure 7: Dimming through LF Clock Input Duty Cyle 11 Current Draw (mA) Figure 5: LF Input Duty Cycle = +50% Figure 4: LF Input Duty Cycle = +10% III. Controlling EL Brightness through Clock Pulse Width Modulation (Option 2) Pulse width modulation of the external HF input signal also may be used to regulate the brightness of the EL lamp. As the positive duty cycle of the HF input signal is increased from 10% to 80%, the peak voltage of the output waveform decrease incrementally to zero output as the inductor charging period is affected by the HF duty cycle. Lamp dimming is thus achieved with pulse width modulation of the HF input signal to the D306A. This scheme may also be used inversely to regulate lamp brightness over the life of the battery or to compensate for lamp aging. Figure 8 shows a typical dimming curve with this technique. The recommended HF duty cycle range is from 10% to 80%. Clocking frequency can range from 20 KHz to 35 KHz. The maximum amplitude of the clock signal may range from 1.0V to Vcc. BAS21 EL Lamp ON OFF Va NC 16 2 NC L 15 3 Cs NC 14 4 Vb GND 13 5 E 6 6.5V 10 kOhm 5.0V Rf 12 Vcc CLF 11 7 NC NC 10 8 NC CHF 9 0.2V Max 1.0V Min 0.2V Max 32 kHz 10% to 80% positive duty PWM D306A Luminance (fL) 800 Hz 10% positive Duty 1.0V Min 24 180 20 150 16 120 12 90 8 60 Luminance Current 4 30 0 0% 10% 20% 30% 40% 50% 60% 70% 80% 0 90% 100% CHF Clock Input Duty Cycle Figure 8: Dimming through HF Clock Input Duty Cyle 12 Current Draw (mA) 2.2nF (200V) 200V 1 Ordering Information: The D306A IC is available in standard SOIC-16 narrow body with heat slug plastic package per tape and reel. A Durel D306A Designer's Kit (1DDD306AA-K01) provides a vehicle for evaluating and identifying the optimum component values for any particular application using D306A. Durel engineers also provide full support to customers including specialized circuit optimization and application retrofits upon request. SOIC-16 with Heat Slug Min. Max. Description mm. in. mm. in. mm. in. M A B C D E F G H I J K L M N 1.372 0.102 0.330 0.864 0.191 9.802 1.016 5.791 3.861 0.052 0.004 0.013 0.034 0.008 0.386 0.040 0.228 0.152 1.550 0.176 0.419 1.042 0.220 9.901 1.270 5.994 3.925 2.794 0.566 1.395 7.112 0.432 0.061 0.007 0.017 0.041 0.009 0.390 0.050 0.236 0.115 0.110 0.022 0.055 0.280 0.017 1.727 0.249 0.508 1.219 0.249 9.999 1.524 6.197 3.988 0.068 0.010 0.020 0.048 0.010 0.394 0.060 0.244 0.157 L N J I K Typical F H D C E A B G SOIC’s are marked with part number (306A) and 3-digit wafer lot code. Bottom of marking is on the Pin 1 side. SOICs in Tape and Reel: 1DDD306AA-S06 Embossed tape on 360 mm diameter reel 2500 units per reel. Quantity marked on reel label. Tape Orientation ISO 9001 Certified DUREL Corporation 2225 W. Chandler Blvd. Chandler, AZ 85224-6155 Tel: (480) 917-6000 FAX: (480) 917-6049 Website: http://www.durel.com The DUREL name and logo are registered trademarks of DUREL CORPORATION. Wave-shaping is a trademark of Durel Corporation. This information is not intended to and does not create any warranties, express or implied, including any warranty of merchantability or fitness for a particular purpose. The relative merits of materials for a specific application should be determined by your evaluation. This driver IC is covered by the following U.S. patents: #5,313,141, #5,789,870, #6,297,597 B1. Corresponding foreign patents are issued and pending. © 2002, 2003 Durel Corporation Printed in U.S.A. 13 LIT-I 9047 Rev. A03