TK6593xM LARGE EL LAMP DRIVER FEATURES APPLICATIONS High Ratio of Brightness / Input PowerBattery Powered Systems Constant Brightness Versus Input Supply ChangesCellular Telephones Optimized for 15 nf to 45 nf Panel Capacitance Pagers Panel Voltage Slew Rates Controlled for Life LCD Modules Enhancement Wrist Watches Panel Peak to Peak Voltage Independent of Input Consumer Electronics Voltage and Temperature The oscillator circuits for the boost converter and lampPanel Peak to Peak Frequency Independent of driver are both internally generated in the TK6593x, without Input Voltage and Temperature the need for external components. The clock frequency of Miniature Package (SOT23L-6) the boost converter is laser-trimmed to ensure good initial Operates with Miniature Coil accuracy that is relatively insensitive to variations in Minimum External Components temperature and supply voltage. The clock frequency of Laser-Trimmed Fixed Frequency Operation the lamp driver tracks the frequency of the boost converter PWM Control Method by a constant scaling factor. Adjustable Output Voltage Furthermore, the drive architecture of the TK6593x hasLower Noise (Audio and EMI) been designed to limit peak drive current delivered to the Intensity Control Application (Refer to Application lamp. This approach limits the slew rate of the voltage Information) across the lamp and has the potential to improve lamp life and decrease RF interference. DESCRIPTION The TK6593x Electroluminescent (EL) Lamp Driver has The TK6593x is available in a miniature, 6-pin been optimized for battery controlled systems where power SOT23L-6 surface mount package. consumption and size are primary concerns. The miniature device size (SOT23L-6), together with the miniature Toko TK6593xM EL coils (D32FU, D31FU, D52FU), further helps system designers reduce the space required to drive the small EL panels. + EL V CC The proprietary architecture (detailed in the Theory of HV GND Operation section) of the TK6593x provides a constant - EL IND output power to the lamp, independent of variations in the battery voltage. This architecture allows the output voltage to remain relatively constant as battery voltages decay, BLOCK DIAGRAM without the need for directly sensing the high voltage output of the EL driver. IND ORDERING INFORMATION HV BOOST V CC CONTROL GND TK6593 MTL HV Lamp Frequency Code OSCILLATOR + EL H BRIDGE - EL TAPE/REEL CODE LAMP FREQUENCY CODE TK65930 175 Hz TK65935* 300 Hz TL: Tape Left TK65931* 200 Hz TK65936 325 Hz TK65932 225 Hz TK65937* 350 Hz * Consult factory for availability TK65933* 250 Hz TK65938 375 Hz of other frequencies. TK65934 275 Hz TK65939* 400 Hz February 2001 TOKO, Inc. Page 1 20P TK6593xM ABSOLUTE MAXIMUM RATINGS V Pin .................................................................... 6.5 V Storage Temperature Range .................... -55 to +150 °C CC All Pins Except V and GND ............................... V Operating Temperature Range .................. -30 to +80 °C CC CLAMP Power Dissipation (Note 1) ................................. 600 mW Junction Temperature .......................................... 150 °C TK6593x ELECTRICAL CHARACTERISTICS V = 3.6 V, T = T = 25 °C, unless otherwise specified. CC A j SR YMBOLPS ARAMETE TN EST CONDITION MP I TX Y MS A UNIT VI7 nput Supply Range 26 . 36 . V CC IQ6 uiescent CurrentC0 urrent into pin 2Aµ0 Q IP) eak Current Threshold(7 Note 4 87971A 0 m PEAK F Lamp Frequency Sz ee Table 1 H LAMP F Boost Frequency Sz ee Table 2 kH BOOST VBnµoost Clamp VoltageF0 orce 100 A into HV pi 9510 0 1V 2 CLAMP DM8 aximum Duty Cycle 82969% (MAX) VP) eak to Peak Lamp Voltage(5 Note 3 10 2 15 4 1V 5 OUT IC) onverter Supply Current(3 Notes 2, 3 SA ee Table m CONV Note 1: Power dissipation is 600 mW when mounted as recommended (200 mW In Free Air). Derate at 4.8 mW/°C for operation above 25 °C. Note 2: Converter supply current is dependent upon the DC resistance of inductor L . Lower DC resistances will result in lower supply currents. 1 Note 3: When using test circuit below. Note 4: Refer to Page 5 graph of Peak Current Threshold vs. Supply Voltage. Gen. Note: Refer to “INDUCTOR VALUE SELECTION” and “INDUCTOR TYPE SELECTION” of Design Considerations Section for choosing inductor. TEST CIRCUIT I CONV + V EL CC V CC HV GND C EL 20 nF - IND EL L 1 330 µH D 1 C 1 Note: L = Toko Low Profile D52FU Series: 875FU-331 M 100 nF 1 D = DIODES INC. DL4148 1 C = AVX 12061C104KAT2A 1 Page 2 February 2001 TOKO, Inc. TK6593xM TK6593x ELECTRICAL CHARACTERISTICS V = 3.6 V, T = T = 25 °C, unless otherwise specified. IN A j TABLE 1: LAMP FREQUENCY TOKO PART NO. MIN. TYP. MAX. TK65930 157 Hz 175 Hz 193 Hz TK65931 180 Hz 200 Hz 220 Hz TK65932 202 Hz 225 Hz 248 Hz TK65933 225 Hz 250 Hz 275 Hz TK65934 247 Hz 275 Hz 303 Hz TK65935 270 Hz 300 Hz 330 Hz TK65936 292 Hz 325 Hz 358 Hz TK65937 315 Hz 350 Hz 385 Hz TK65938 337 Hz 375 Hz 413 Hz TK65939 360 Hz 400 Hz 440 Hz TABLE 2: OSCILLATOR FREQUENCY TOKO PART NO. MIN. TYP. MAX. TK65930 20.1 kHz 22.4 kHz 24.7 kHz TK65931 23.0 kHz 25.6 kHz 28.2 kHz TK65932 25.9 kHz 28.8 kHz 31.7 kHz TK65933 28.8 kHz 32.0 kHz 35.2 kHz TK65934 31.6 kHz 35.2 kHz 38.8 kHz TK65935 34.5 kHz 38.4 kHz 42.3 kHz TK65936 37.4 kHz 41.6 kHz 45.8 kHz TK65937 40.3 kHz 44.8 kHz 49.3 kHz TK65938 43.2 kHz 48.0 kHz 52.8 kHz TK65939 46.1 kHz 51.2 kHz 56.3 kHz TABLE 3: CONVERTER SUPPLY CURRENT TOKO PART NO. MIN. TYP. MAX. TK65930 - 14.2 mA 28.4 mA TK65931 - 16.2 mA 32.4 mA TK65932 - 18.3 mA 36.6 mA TK65933 - 20.3 mA 40.6 mA TK65934 - 22.3 mA 44.6 mA TK65935 - 24.3 mA 48.6 mA TK65936 - 26.4 mA 52.8 mA TK65937 - 28.4 mA 56.8 mA TK65938 - 30.4 mA 60.8 mA TK65939 - 32.4 mA 64.8 mA February 2001 TOKO, Inc. Page 3 TK6593xM TYPICAL PERFORMANCE CHARACTERISTICS USING TEST CIRCUIT TK65939 Voltage Waveform TK65931 Voltage Waveform TK65931 TK65939 PEAK TO PEAK LAMP VOLTAGE PEAK TO PEAK LAMP VOLTAGE vs. SUPPLY VOLTAGE vs. SUPPLY VOLTAGE 150 140 L = 330 µH 140 1 130 L = 330 µH 1 130 120 L = 220 µH 120 1 L = 220 µH 1 110 110 100 100 2.5 3 3.5 4 4.5 5 5.5 6 2.5 3 3.5 4 4.5 5 5.5 6 V (V) V (V) CC CC TK65931 TK65939 LAMP FREQUENCY LAMP FREQUENCY vs. SUPPLY VOLTAGE vs. SUPPLY VOLTAGE 230 460 220 440 210 420 200 400 190 380 180 360 2.5 3 3.5 4 4.5 5 5.5 6 2.5 3 3.5 4 4.5 5 5.5 6 V (V) V (V) CC CC Page 4 February 2001 TOKO, Inc. V (V) F (Hz) OUT LAMP F (Hz) V (V) LAMP OUT TK6593xM TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) USING TEST CIRCUIT TK65931 TK65939 AVERAGE CONVERTER SUPPLY AVERAGE CONVERTER SUPPLY CURRENT vs. SUPPLY VOLTAGE CURRENT vs. SUPPLY VOLTAGE 30 60 25 50 20 40 15 30 10 20 5 10 0 0 2.5 3 3.5 4 4.5 5 5.5 6 2.5 3 3.5 4 4.5 5 5.5 6 V (V) V (V) CC CC TK65931 TK65939 PEAK CURRENT THRESHOLD PEAK CURRENT THRESHOLD vs. SUPPLY VOLTAGE vs. SUPPLY VOLTAGE 110 110 100 100 90 90 80 80 70 70 60 60 2.5 3 3.5 4 4.5 5 5.5 6 2.5 3 3.5 4 4.5 5 5.5 6 V (V) V (V) CC CC TK65931 TK65939 QUIESCENT CURRENT QUIESCENT CURRENT vs. SUPPLY VOLTAGE vs. SUPPLY VOLTAGE 200 200 150 150 100 100 50 50 0 0 2.5 3 3.5 4 4.5 5 5.5 6 2.5 3 3.5 4 4.5 5 5.5 6 V (V) V (V) CC CC February 2001 TOKO, Inc. Page 5 I (µA) I (mA) I (mA) Q PEAK CONV I (µA) I (mA) I (mA) Q PEAK CONV TK6593xM TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) USING TEST CIRCUIT TK65939 TK65931 PEAK TO PEAK LAMP VOLTAGE PEAK TO PEAK LAMP VOLTAGE vs. TEMPERATURE vs. TEMPERATURE 160 160 150 150 V = 3.6 V CC 140 140 V = 3.6 V CC 130 130 V = 2.7 V CC V = 2.7 V CC 120 120 110 110 100 100 90 90 -50 -25 0 25 50 75 100 125 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TK65931 TK65939 LAMP FREQUENCY LAMP FREQUENCY vs. TEMPERATURE vs. TEMPERATURE 220 440 210 420 200 400 190 380 180 360 170 340 -50 -25 0 25 50 75 100 125 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TK65931 TK65939 AVERAGE CONVERTER SUPPLY AVERAGE CONVERTER SUPPLY CURRENT vs. TEMPERATURE CURRENT vs. TEMPERATURE 25 45 20 40 15 35 10 30 5 25 0 20 -50 -25 0 25 50 75 100 125 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) Page 6 February 2001 TOKO, Inc. I (mA) F (Hz) V (V) CONV LAMP OUT F (Hz) V (V) I (mA) LAMP OUT CONV TK6593xM TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) USING TEST CIRCUIT TK65931 TK65939 PEAK CURRENT THRESHOLD PEAK CURRENT THRESHOLD vs. TEMPERATURE vs. TEMPERATURE 110 110 V = 3.6 V = 3.6 V CC CC 100 100 90 90 V = 2.7 V = 2.7 V CC CC 80 80 70 70 60 60 -50 -25 0 25 50 75 100 125 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TK65939 TK65931 QUIESCENT CURRENT QUIESCENT CURRENT vs. TEMPERATURE vs. TEMPERATURE 120 100 110 90 100 80 µµ 90 70 80 60 70 50 -50 -25 0 25 50 75 100 125 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) February 2001 TOKO, Inc. Page 7 I ( A) I (mA) Q PEAK I ( A) I (mA) Q PEAK TK6593xM TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) USING D TEST CIRCUIT (MAX) TK65931 TK65939 MAXIMUM DUTY CYCLE MAXIMUM DUTY CYCLE vs. SUPPLY VOLTAGE vs. SUPPLY VOLTAGE 95 95 94 94 93 93 92 92 91 91 90 90 2.5 3 3.5 4 4.5 5 5.5 6 2.5 3 3.5 4 4.5 5 5.5 6 V (V) V (V) CC CC TK65931 TK65939 MAXIMUM DUTY CYCLE MAXIMUM DUTY CYCLE vs. TEMPERATURE vs. TEMPERATURE 95 95 94 94 93 93 92 92 91 91 90 90 -50 -25 0 25 50 75 100 125 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) D TEST CIRCUIT (MAX) + EL V CC V CC HV GND - IND EL R 1 Note: R = 470 ý 1 Page 8 February 2001 TOKO, Inc. D (%) D (%) (MAX) (MAX) D (%) D (%) (MAX) (MAX) TK6593xM THEORY OF OPERATION An Electroluminescent (EL) Lamp is a strip of plastic, clock is generated by dividing the high frequency clock by coated with a phosphorous material that emits light when 128; this lower frequency clock corresponds to the drive a high voltage AC signal is applied to the terminals of the frequency of the EL Lamp. The laser-trimmed oscillators device. EL panels have the ability to light the entire panel are relatively insensitive to variations in temperature and uniformly. Because of this, they are gradually becoming supply voltage. Therefore, they provide good control of the more popular and widespread than LEDs. The amount of lamp color emitted by the panel. light emitted from an EL Lamp is typically proportional to the magnitude of the voltage applied to the lamp. The circuit below illustrates a typical application where the Furthermore, the color of the light emitted by an EL Lamp TK6593x is driving a 3-square-inch EL Lamp with a is somewhat dependent upon the frequency of the applied capacitance of approximately 20 nF. drive signal. For most applications, a peak-to-peak voltage of 100 to 170 V, with a drive frequency of 175 to 400 Hz, provides optimal trade-off between lamp intensity and I CONV + EL V CC power consumption. V CC HV GND C EL The capacitance of the EL Panel is typically proportional to 20 nF the size of the lamp (a 1 square inch EL Panel typically - EL IND exhibits approximately 5 nF of capacitance load). The L 1 TK6593x series of devices has been optimized to drive EL 330 µH panels, which are approximately 3-6 square inches in size. D 1 C 1 The Boost section of the TK6593x consists of a controller 100 nF for stepping up a relatively low voltage (2.7 to 6 V) to a much higher voltage (50 to 90 V) needed to drive the EL Lamp. The boost section of the TK6593x uses a proprietary architecture which provides a relatively constant output FIGURE 1: TYPICAL APPLICATION power, independent of the input supply, without the need for sensing the high voltage output of the boost converter. By controlling the peak current through the switching By keeping the ratio of the boost frequency and the H- element of the boost converter, the boost section provides Bridge frequency constant, the peak-to-peak output voltage a constant output power independent of the input supply. from the TK6593x becomes primarily dependent upon the capacitance of the EL Lamp, the peak current threshold of The H-Bridge section of the TK6593x switches the high the boost converter, and the value of the inductive element voltage output of the boost converter to the two terminals used in the boost converter. For the TK6593x, the peak of the EL Lamp. By alternately switching the terminals of current threshold is laser-trimmed to 97 mA. The capacitive the lamp between the high voltage supply and ground, the load of the EL Lamp is a function of panel size and is peak-to-peak voltage developed across the lamp is typically fixed. Therefore, the high voltage output of the effectively twice the high voltage generated by boost boost converter can be set to a desired voltage by selecting converter. Furthermore, the TK6593x limits the magnitude the appropriate value of the inductive element used in the of the drive currents through the H-Bridge switches in boost converter. order to minimize the edge rates developed across the EL I = Boost Peak Current Threshold (97 mA) Lamp. This approach protects the EL Panel from large PEAK current spikes and reduces the likelihood of high frequency C = Capacitance of EL Lamp noise components being injected into neighboring circuitry. EL L = Inductance Value The Oscillator section of the TK6593x generates a fixed frequency clock source for the previously described Boost V = (I / 2) x (L /C ) x 128 and H-Bridge sections, without the need for external HV PEAK EL components. The high frequency output of the oscillator is used for driving the boost controller. A lower frequency February 2001 TOKO, Inc. Page 9 TK6593xM THEORY OF OPERATION (CONT.) HV With properly selected components, the TK6593x will HVP HVP UL UR nominally support peak output voltages to 90 V - + EL EL (180 V ). Should the EL Panel become disconnected PK-PK EL Panel from the driver outputs, the removal of the load can cause the output voltage to increase beyond 90 V. To protect LL LR against this fault condition, a clamp circuit exists on the high voltage output which nominally limits the output Current Source 2 Current Source 1 voltage to a typical value of 105 V (210 V ). PK-PK DETAILS CONCERNING THE H-BRIDGE SECTION OPERATION FIGURE 2: H-BRIDGE SCHEMATIC In an effort to extend EL lamp life, reduce EMI emissions, and reduce the power draw of the IC, current sources to control the charging and discharging of the EL lamp panel and special sequencing control of the H-bridge FETs were BOTH OFF added to the H-bridge of TK659xx. Current sources were added between ground and the UL OFF OFF OFF ON sources of the low-side N-channel FETs (Figure 2). Therefore, the current into and out of the EL panel is UR OFF OFF OFF ON controlled and limited. BOTH ON LL ON OFF ON ON The FETs are turned off and on in the sequence shown in ON LR ON ON OFF Figure 3. As is noted in Figure 3, there is a period of time when both of lower N-channel FETs are turned on and both of upper P-channel FETs are turned off. This provides a - V EL period of time to discharge the EL panel capacitance completely; before starting to recharge it again with current from HV voltage rail. Therefore, this special sequencing method prevents taking current off the HV voltage rail + V EL during the discharge of EL panel capacitance and operates more efficiently. Discharging EL Panel Capacitance + - V = V V EL EL - EL FIGURE 3: H-BRIDGE SEQUENCING WAVEFORMS Page 10 February 2001 TOKO, Inc. TK6593xM PIN DESCRIPTIONS SUPPLY PIN (V ) CC This pin is the positive input supply for the TK6593x. Good design practices dictate capacitive decoupling to the ground pin. GROUND PIN (GND) The pin provides the ground connection for the IC. IND PIN This pin is periodically pulled to ground by a power transistor acting as an internal switch to the TK6593x. Externally, this pin is typically connected to an inductor and a rectifying diode. By modulating the switching action of the internal switch, the TK6593x can boost the relatively low voltage of the battery to the high voltage required to drive the EL Lamp. HV PIN This pin is connected to the filter capacitor and the cathode of the rectifying diode in order to generate a high voltage supply. This high voltage supply is switched to the terminals of the EL Lamp through the H-Bridge. + EL PIN This pin is connected to one side of the EL Panel. - EL PIN This pin is connected to the other side of the EL Panel. + - Note: Measuring the voltage across the EL lamp (EL pin to EL pin) should be done with balanced scope probes using differential measurement techniques to obtain a true waveform of the voltage across the EL lamp. February 2001 TOKO, Inc. Page 11 TK6593xM DESIGN CONSIDERATIONS INDUCTOR VALUE SELECTION Designing an EL Driver utilizing the TK6593x is a very simple task. The primary component affecting the behavior of the converter is the inductor. Essentially, the entire design task primarily consists of selecting the proper inductor value and type given the operating conditions of the EL Panel (e.g., lamp capacitance, frequency, output voltage, supply range). The following tables and charts are intended to simplify the selection of the inductor. Given the capacitance of the EL Lamp, and the peak output voltage requirements, the following table can be utilized to select the value of the inductive component. TABLE 4: PEAK OUTPUT VOLTAGE VS. INDUCTOR VALUE AND LAMP CAPACITANCE INDUCTOR 15.0 nF 20.0 nF 25.0 nF 30.0 nF 35.0 nF 40.0 nF 45.0 nF VALUE LAMP LAMP LAMP LAMP LAMP LAMP LAMP µ1V 00 H 4V 5 3V 9 3V 5 3V 2 2V 9 2V 7 26 µ1V 20 H 4V 9 4V 3 3V 8 3V 5 3V 2 3V 0 28 µ1V 50 H 5V 5 4V 8 4V 3 3V 9 3V 6 3V 4 32 µ1V 80 H 6V 0 5V 2 4V 7 4V 3 3V 9 3V 7 35 µ2V 20 H 6V 6 5V 8 5V 1 4V 7 4V 4 4V 1 38 µ2V 70 H 7V 4 6V 4 5V 7 5V 2 4V 8 4V 5 43 µ3V 30 H 8V 1 7V 0 6V 3 5V 8 5V 3 5V 0 47 µ3V 90 H 8V 8 7V 7 6V 9 6V 3 5V 8 5V 4 51 µ4V 70 H 8V 4 7V 5 6V 9 6V 4 5V 9 56 µ5V 60 H 8V 2 7V 5 6V 9 6V 5 61 µ6V 80 H 8V 3 7V 6 7V 2 67 820µH 8V 4 V 7V 9 74 Close to 100 V operation check capacitor C voltage rating 1000µH 8V 7 V 82 1 Note: The voltages indicated in the table above may not be achievable under certain circumstances (i.e., low battery or higher drive frequencies). Refer to the charts on page 12 to determine which output voltage/coil combination can be supported by the EL driver. As an example as to how the above table is to be used, assume that we have a 4-square-inch panel (30 nF capacitance) and we would like the peak-to-peak voltage across the lamp to be 140 V. The peak voltage on either terminal would be 70 V (140 V / 2). Referring to the table above, we can see that using a 470 µH coil the peak voltage developed across a 30 nF Lamp would be approximately 69 V. In this particular example, the inductive component should have a value of 470 µH. INDUCTOR TYPE SELECTION After the value of the inductor has been selected, an appropriate coil type needs to be selected taking into account such factors as DC resistance and current capability. The following charts can be utilized for selecting the proper family of Toko Coils. Furthermore, the following charts will also indicate if the TK6593x is the appropriate driver given the frequency and input supply requirements. The following charts will indicate whether or not the TK6593x has sufficient drive capability, Page 12 February 2001 TOKO, Inc. TK6593xM DESIGN CONSIDERATIONS (CONT.) given the input supply and frequency requirements. A high-current solution for driving larger panels is currently under development. To utilize the following charts in selecting an appropriate coil, perform the following steps: 1) From the following charts, select the chart that matches the part number of the Toko EL Driver that will be used in the application. The part number of the Toko EL Driver will be dependant upon the desired frequency of the EL panel (e.g., TK65931 = 200Hz). 2) Determine input supply voltage range (e.g., 4 to 6 V). The x-axis of the following charts represent the minimum expected supply voltage. Below this minimum supply voltage the EL Driver output may begin to droop. On the appropriate chart, draw a vertical line upward from the minimum supply voltage represented on the x-axis (e.g., 4V). 3) Draw a horizontal line passing through the chosen inductor value on the y-axis (e.g., 470 µH). 4) The vertical and horizontal lines drawn in steps 2 and 3 respectively will intersect at a point. This point will lie in one of four regions of the chart (e.g., D52FU). These four regions suggest which family of Toko Coils to use. Of the three coil families suggested in these charts, the D31FU has the smallest physical size but also has higher DC resistance. The D52FU series of coils has the largest physical size and the lowest DC resistance. The D52FU or the D32FU can be used as a reasonable substitute for the D31FU. Similarly, the D52FU can be used as a replacement for the D32FU. Substituting a coil with lower DC resistance will generally result in a system that will consume less power supply current. TK65934, TK65935 TK65930, TK65931 TK65932, TK65933 (NOTE 1) (NOTE 1) (NOTE 1) 1000 1000 1000 D52FU 820 820 820 µµ D52FU D52FU 680 680 680 560 560 560 X 470 470 470 390 390 390 D32FU D32FU D32FU 330 330 330 270 270 270 220 D31FU 220 D31FU 220 D31FU 180 180 180 100 100 100 3 4 5 6 3 4 5 6 3 4 5 6 MINIMUM SUPPLY (V) MINIMUM SUPPLY (V) MINIMUM SUPPLY (V) TK65936, TK65937 TK65938, TK65939 1000 (NOTE 1) 1000 (NOTE 1) 820 820 µµ 680 680 560 560 D52FU D52FU 470 470 390 390 D32FU D32FU 330 330 Note 1: A high-current solution for driving larger panels is currently under development. 270 270 220 220 D31FU D31FU 180 180 100 100 3 4 5 6 3 4 5 6 MINIMUM SUPPLY (V) MINIMUM SUPPLY (V) February 2001 TOKO, Inc. Page 13 INDUCTOR VALUE ( H) INDUCTOR VALUE ( H) INDUCTOR VALUE ( H) INDUCTOR VALUE (µH) INDUCTOR VALUE ( H) TK6593xM APPLICATION INFORMATION EL LAMP INTENSITY CONTROL APPLICATION In driving EL lamp panels, it is sometimes desirable to be able to adjust the intensity of the EL lamp. The TK6593x can be used in such an application. By reducing the voltage supplied to the V pin of the TK6593x, one can reduce the peak CC current regulation point of the IC. This translates into a reduction in the peak to peak output voltage across the EL panel, which reduces the intensity of the light being emitted from the EL lamp. By decreasing the input voltage to the V pin from 2.9 V to 2.1 V, the peak current regulation point will be reduced about CC 53 mA. This correlates to about a 2/3 reduction in the peak to peak voltage appearing across the EL lamp panel. The V pin only takes 200 µA max. when the EL driver is in operation. Therefore, it can normally be controlled by logic CC power level signals. One way of accomplishing this with two digital logic signals is shown in Figure 4. R = 1.5 kΩ 1 3 V ~ 1 mA source R = 3.0 kΩ 2 C = 10 nF 2 R 1 1.5 k + V 3 V PWM EL CC 10% to 90% 200 KHz to 300 KHz C R ~ 1 mA sink 2 2 HV GND 10 nF 3 k C EL 20 nF - EL IND Vpower L 1 1.8 to 7 V D 1 C 1 100 nF FIGURE 4: INTENSITY CONTROL APPLICATION NOISE CONSIDERATIONS There are two specific noise types relevant to the user when it comes to choosing EL Drivers: the Audio Noise and the Electromagnetic Interference (EMI) Noise. The EMI Noise would most likely come from the boost converter section of the EL Driver circuit. The Toko EL Driver has specifically been designed to address this issue. The device runs at a fixed frequency and the frequency is controlled tightly in order to avoid interference. Furthermore, the panel frequency is forced to be a 128 submultiple of the boost frequency avoiding any type of beating frequencies. By choosing shielded coils, the EMI noise problem can further be reduced. The Audio Noise can come from several components which make up the system. The coil, if operated in the audio range would be a source of noise. The Toko EL Driver was carefully designed to give the user the choice of 10 frequencies such that the coil frequency will always be above audio range. Since the device operates at a fixed frequency in discontinuous conduction mode, there are no possible submultiples which would cause audible noise. The filter capacitor can be a source of audio noise. Furthermore, depending on how this cap is mounted, the mounting can act as an amplifier (as a speaker box). Certain ceramic caps driven from a high voltage source as in the EL Driver case, demonstrate a PIEZOELECTRIC effect which is distinguishable in the Audio Range. Other types of caps, such as film type do not denote an audio noise. The panel itself, being operated well into the Audio Range (175 Hz to 400 Hz) and of a capacitive nature driven from high voltage may also display Audible Noise. Mounting of this panel can enhance or diminish this natural effect of the panel. Page 14 February 2001 TOKO, Inc. TK6593xM LAYOUT Actual Size 2x SPLIT SUPPLY LAYOUT Actual Size 2x February 2001 TOKO, Inc. Page 15 TK6593xM PACKAGE OUTLINE Marking Information SOT23L-6 Marking +0.15 0.4 - 0.05 TK65930 C0 0.1 M 0.6 TK65931 C1 6 TK65932 C2 TK65933 C3 Marking TK65934 C4 TK65935 C5 TK65936 C6 TK65937 C7 TK65938 C8 TK65939 C9 +0.15 123 - 0.05 0.32 e e 0.1 0.95 0.95 M 5 PL e e 0.95 0.95 Recommended Mount Pad +0.3 - 0.1 3.5 2.2 (3.4) 0.4 + 0.3 3.3 Dimensions are shown in millimeters Tolerance: x.x = ± 0.2 mm (unless otherwise specified) Toko America, Inc. Headquarters 1250 Feehanville Drive, Mount Prospect, Illinois 60056 Tel: (847) 297-0070 Fax: (847) 699-7864 TOKO AMERICA REGIONAL OFFICES Midwest Regional Office Western Regional Office Semiconductor Technical Support Toko America, Inc. Toko America, Inc. Toko Design Center 1250 Feehanville Drive 2480 North First Street , Suite 260 4755 Forge Road Mount Prospect, IL 60056 San Jose, CA 95131 Colorado Springs, CO 80907 Tel: (847) 297-0070 Tel: (408) 432-8281 Tel: (719) 528-2200 Fax: (847) 699-7864 Fax: (408) 943-9790 Fax: (719) 528-2375 Visit our Internet site at http://www.tokoam.com The information furnished by TOKO, Inc. is believed to be accurate and reliable. However, TOKO reserves the right to make changes or improvements in the design, specification or manufacture of its products without further notice. TOKO does not assume any liability arising from the application or use of any product or circuit described herein, nor for any infringements of patents or other rights of third parties which may result from the use of its products. No license is granted by implication or otherwise under any patent or patent rights of TOKO, Inc. Page 16 February 2001 TOKO, Inc. © 1999 Toko, Inc. IC-xxx-TK6593x Printed in the USA All Rights Reserved 0798O0.0K 1.4 max 0 - 0.1 1.2 +0.15 - 0.05 0.3 0.15 1.0 e1 3.0 15 max