EL7513 ® Data Sheet March 14, 2006 White LED Step-Up Regulator Features The EL7513 is a constant current boost regulator specially designed for driving white LEDs. It can drive 4 LEDs in series or up to 12 LEDs in parallel/series configuration and achieves efficiency up to 91%. • 2.6V to 13.2V input voltage The brightness of the LEDs is adjusted through a voltage level on the CNTL pin. When the level falls below 0.1V, the chip goes into shut-down mode and consumes less than 1µA of supply current for VIN less than 5.5V. • 1MHz switching frequency The EL7513 is available in the 8 Ld TSOT and 8 Ld MSOP packages. The TSOT package is just 1mm high, compared to 1.45mm for the standard SOT23 package. Ordering Information PART NUMBER FN7112.4 • 18V maximum output voltage • Drives up to 12 LEDs • Up to 91% efficiency • 1µA maximum shut-down current • Dimming control • 8 Ld TSOT and 8 Ld MSOP packages • Pb-free plus anneal available (RoHS compliant) Applications PART TAPE & MARKING REEL PACKAGE PKG. DWG. # EL7513IWT-T7 9 7” 8 Ld TSOT (3k pcs) MDP0049 EL7513IWT-T7A 9 7” 8 Ld TSOT (250 pcs) MDP0049 EL7513IWTZ-T7 (See Note) BAAA 7” 8 Ld TSOT (3k pcs) (Pb-Free) MDP0049 EL7513IWTZ-T7A BAAA (See Note) 7” 8 Ld TSOT (250 pcs) (Pb-Free) MDP0049 • PDAs • Cellular phones • Digital cameras EL7513IY d - 8 Ld MSOP MDP0043 EL7513IY-T7 d 7” 8 Ld MSOP MDP0043 EL7513IY-T13 d 13” 8 Ld MSOP MDP0043 EL7513IYZ (See Note) BAABA - 8 Ld MSOP MDP0043 (Pb-Free) EL7513IYZ-T7 (See Note) BAABA 7” 8 Ld MSOP MDP0043 (Pb-Free) EL7513IYZ-T13 (See Note) BAABA 13” 8 Ld MSOP MDP0043 (Pb-Free) • White LED backlighting NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2004-2006. All Rights Reserved All other trademarks mentioned are the property of their respective owners. EL7513 Pinouts Typical Connection EL7513 (8 LD TSOT) TOP VIEW L 2.6V TO 5.5V C1 4.7µF COMP 1 8 VIN CNTL 2 7 CS VOUT 3 6 SGND LX 4 5 PGND D C2 33µH 1µF VIN LX VOUT CS EL7513 (8 LD MSOP) TOP VIEW VCTRL C3 CS 1 8 CNTL VIN 2 7 COMP PGND 3 6 LX SGND 4 5 VOUT 2 0.1µF CNTL PGND COMP SGND R1 5Ω EL7513 Absolute Maximum Ratings (TA = 25°C) COMP, CNTL, CS to SGND. . . . . . . . . . . . . . . . . . . . . . -0.3V to +6V VIN to SGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+14V VOUT to SGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+19V LX to PGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+20V SGND to PGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +0.3V Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C Ambient Operating Temperature . . . . . . . . . . . . . . . .-40°C to +85°C CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. This part is ESD sensitive. Handle with care. IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typ values are for information purposes only. Unless otherwise noted, all tests are at the specified temperature and are pulsed tests, therefore: TJ = TC = TA Electrical Specifications VIN = 3V, VO = 12V, C1 = 4.7µF, L = 33µH, C2 = 1µF, C3 = 0.1µF, R1 = 5Ω, TA = 25°C, Unless Otherwise Specified PARAMETER DESCRIPTION CONDITIONS MIN TYP 2.6 MAX UNIT 13.2 V 1 µA VIN Input Voltage IQ1 Total Input Current at Shut-down VCNTL = 0V IQ1 Quiescent Supply Current at VO Pin VCNTL = 1V, load disconnected 1 1.5 mA ICOMP COMP Pin Pull-up Current COMP connected to SGND 11 20 µA VCOMP COMP Voltage Swing 1.5 2.5 V ICNTL CNTL Shut-down Current 1 µA VCNTL1 Chip Enable Voltage VCNTL2 Chip Disable Voltage 0.5 CNTL = 0V 240 mV 100 mV IOUT_ACCURACY VCNTL = 1V VCNTL = 1V 14 15 16 mA VOUT1 Over-voltage Threshold VOUT rising 17 18 19 V VOUT2 Over-voltage Threshold VOUT falling, with resistive load 15 16 17.5 V ILX MOSFET Current Limit RDS_ON MOSFET On-resistance ILEAK MOSFET Leakage Current FS Switching Frequency DMAX Maximum Duty Ratio ICS CS Input Bias Current ∆IO/∆VIN Line Regulation 500 mA Ω 0.7 VCNTL = 0V, VLX = 12V VCNTL = 2V, IS = 0 800 1000 85 90 1 µA 1200 kHz % 1 VIN = 2.6V - 5.5V 0.03 µA %/V Pin Descriptions 8 LD TSOT 8 LD MSOP PIN NAME DESCRIPTION 1 7 COMP Compensation pin. A compensation cap (4700pF to 1µF) is normally connected between this pin and SGND. 2 8 CNTL Control pin for dimming and shut-down. A voltage between 250mV and 5.5V controls the brightness, and less than 100mV shuts down the converter. 3 5 VOUT Output voltage sense. Use for over voltage protection. 4 6 LX Inductor connection pin. The drain of internal MOSFET. 5 3 PGND Power Ground pin. The source of internal MOSFET. 6 4 SGND Signal Ground. Ground pin for internal control circuitry. Needs to connect to PGND at only one point. 7 1 CS Current sense pin. Connect to sensing resistor to set the LED bias current. 8 2 VIN Power supply for internal control circuitry. 3 EL7513 Block Diagram 2.6V TO 5.5V CIN VIN 4.7µF REFERENCE GENERATOR 1MHz OSCILLATOR THERMAL SHUTDOWN OVER-VOLTAGE PROTECTION L 33µH VOUT LX COMP + + + CCOMP COUT PWM LOGIC 1µF I(LED) BOOST I-SENSE 0.1µF START-UP CONTROL PWM SIGNAL VCNTL ERROR AMP + - 617K CNTL PGND CS 5Ω 50K SGND Typical Performance Curves All performance curves and waveforms are taken with C1 = 4.7µF, C2 = 1µF, C3 = 0.1µF, L = 33µF, VIN = 3.3V, VCNTL = 1V, R1 = 5Ω, 4 LEDs in a series; unless otherwise specified. 1.05 3.5 3 1.04 VCNTL=0V, 0.1V WHITE LEDs DISCONNECTED 1.03 IIN (µA) FS (MHz) 2.5 1.02 2 1.5 1 1.01 1 2.5 0.5 3 4 3.5 4.5 5 VIN (V) FIGURE 1. SWITCHING FREQUENCY vs VIN 4 5.5 0 2.5 4.5 6.5 8.5 10.5 12.5 VIN (V) FIGURE 2. QUIESCENT CURRENT 14.5 EL7513 Typical Performance Curves (Continued) All performance curves and waveforms are taken with C1 = 4.7µF, C2 = 1µF, C3 = 0.1µF, L = 33µF, VIN = 3.3V, VCNTL = 1V, R1 = 5Ω, 4 LEDs in a series; unless otherwise specified. VCNTL=1V 16 35 15.8 30 15.6 15.4 ILED (mA) ILED (mA) 25 20 15 15 14.8 14.6 10 14.4 5 0 15.2 14.2 0 0.5 1 1.5 2 14 2.5 2.5 3 4 VIN (V) 3.5 VCNTL (V) FIGURE 3. ILED vs VCNTL 5.5 FIGURE 4. ILED vs VIN BAT54HT1 L VIN 5 4.5 33µH 4.7µF 1µF 90 2 LEDs IN A SERIES VIN=4.2V VIN LX VOUT CS VCTRL 2 1 CNTL PGND COMP SGND 4 EFFICIENCY (%) 8 85 3 7 5Ω 5 6 VIN=2.7V 80 75 70 0.1µF L=COILCRAFT LPO1704-333CM 5 10 15 20 25 30 IO (mA) FIGURE 5A. 2 LEDs IN A SERIES BAT54HT1 L VIN 33µH 4.7µF 3 LEDs IN A SERIES 1µF VIN LX VOUT CS 2 1 CNTL PGND COMP SGND 90 3 7 5 VIN=4.2V 85 4 EFFICIENCY (%) 8 VCTRL FIGURE 5B. EFFICIENCY vs IO FIGURE 5. 5Ω 6 VIN=2.7V 80 75 70 0.1µF L=COILCRAFT LPO1704-333CM 5 10 15 20 25 IO (mA) FIGURE 6A. 3 LEDs IN A SERIES 5 FIGURE 6. FIGURE 6B. EFFICIENCY vs IO 30 EL7513 Typical Performance Curves (Continued) All performance curves and waveforms are taken with C1 = 4.7µF, C2 = 1µF, C3 = 0.1µF, L = 33µF, VIN = 3.3V, VCNTL = 1V, R1 = 5Ω, 4 LEDs in a series; unless otherwise specified. BAT54HT1 L VIN 33µH 4.7µF 4 LEDs IN A SERIES 1µF 90 VIN=4.2V VIN LX VOUT CS 2 VCTRL 1 CNTL PGND COMP SGND 85 4 EFFICIENCY (%) 8 3 7 5Ω 5 6 VIN=2.7V VIN=3.3V 80 75 70 0.1µF L=COILCRAFT LPO1704-333CM 5 10 15 20 25 30 LED CURRENT (mA) FIGURE 7A. 4 LEDs IN A SERIES BAT54HT1 L VIN FIGURE 7B. EFFICIENCY vs IO FIGURE 7. 33µH 4.7µF 90 1µF 2 LEGS OF 2 LEDs IN A SERIES VIN=4.2V VIN LX VOUT CS VCTRL 2 1 CNTL PGND COMP SGND 85 4 EFFICIENCY (%) 8 3 7 5Ω 5 5Ω 6 VIN=2.7V 80 75 70 10 0.1µF L=COILCRAFT LPO1704-333CM 20 30 40 50 60 IO (mA) FIGURE 8A. 2 LEGS OF 2 LEDs IN A SERIES BAT54HT1 L VIN FIGURE 8B. EFFICIENCY vs IO FIGURE 8. 2 LEGS OF 3 LEDs IN A SERIES 33µH 4.7µF 90 1µF VIN=4.2V VIN LX VOUT CS VCTRL 2 1 CNTL PGND COMP SGND 85 4 EFFICIENCY (%) 8 3 7 5 5Ω 5Ω 6 VIN=2.7V 80 75 70 10 0.1µF L=SUMIDA CMD13D13-33µH 20 30 40 50 IO (mA) FIGURE 9A. 2 LEGS OF 3 LEDs IN A SERIES 6 FIGURE 9. FIGURE 9B. EFFICIENCY vs IO 60 EL7513 Typical Performance Curves (Continued) All performance curves and waveforms are taken with C1 = 4.7µF, C2 = 1µF, C3 = 0.1µF, L = 33µF, VIN = 3.3V, VCNTL = 1V, R1 = 5Ω, 4 LEDs in a series; unless otherwise specified. BAT54HT1 L VIN 33µH 4.7µF 1µF 2 LEGS OF 4 LEDs IN A SERIES 90 VIN LX VOUT CS 2 VCTRL 1 CNTL PGND COMP SGND VIN=4.2V 4 EFFICIENCY (%) 8 3 7 5Ω 5 5Ω 85 80 VIN=2.7V 75 L=SUMIDA CMD13D13-33µH 6 70 10 0.1µF 20 30 40 50 60 IO (mA) FIGURE 10A. 2 LEGS OF 4 LEDs IN A SERIES VIN FIGURE 10B. EFFICIENCY vs IO FIGURE 10. BAT54HT1 L 15µH 4.7µF 1µF 95 VIN LX VOUT VCTRL CS 2 1 CNTL PGND COMP SGND 4 EFFICIENCY (%) 8 3 7 5Ω 5 5Ω 5Ω 3 LEGS OF 2 LEDs IN A SERIES 90 VIN=4.2V 85 VIN=2.7V 80 75 6 70 15 0.1µF L=SUMIDA CMD13D13-15µH 35 55 75 95 IO (mA) FIGURE 11A. 3 LEGS OF 2 LEDs IN A SERIES VIN FIGURE 11B. EFFICIENCY vs IO FIGURE 11. BAT54HT1 L 15µH 4.7µF 1µF 95 VIN LX VOUT CS VCTRL 2 1 CNTL PGND COMP SGND 4 VIN=4.2V 90 EFFICIENCY (%) 8 3 LEGS OF 3 LEDs IN A SERIES 3 7 5Ω 5 5Ω 5Ω 85 VIN=2.7V 80 75 6 70 15 0.1µF L=SUMIDA CMD13D13-15µH 35 55 75 IO (mA) FIGURE 12A. 3 LEGS OF 3 LEDs IN A SERIES 7 FIGURE 12. FIGURE 12B. EFFICIENCY vs IO 95 EL7513 Typical Performance Curves (Continued) All performance curves and waveforms are taken with C1 = 4.7µF, C2 = 1µF, C3 = 0.1µF, L = 33µF, VIN = 3.3V, VCNTL = 1V, R1 = 5Ω, 4 LEDs in a series; unless otherwise specified. VIN BAT54HT1 L 15µH 4.7µF 1µF 95 VIN LX VOUT CS VCTRL 2 1 CNTL PGND COMP SGND 4 90 EFFICIENCY (%) 8 3 LEGS OF 4 LEDs IN A SERIES 3 7 5Ω 5 5Ω 5Ω VIN=4.2V 85 VIN=2.7V 80 75 6 70 15 0.1µF L=SUMIDA CMD13D13-15µH 35 55 75 95 IO (mA) FIGURE 13A. 3 LEGS of 4 LEDs in a SERIES FIGURE 13B. EFFICIENCY vs IO FIGURE 13. Waveforms All performance curves and waveforms are taken with C1 = 4.7µF, C2 = 1µF, C3 = 0.1µF, L = 33µF, VIN = 3.3V, VCNTL = 1V, R1 = 5Ω, 4 LEDs in a series; unless otherwise specified. C3=4700pF 50mA/DIV IIN VIN 2V/DIV IIN 50mA/DIV VCNTL 1V/DIV ILED VCNTL 1V/DIV ILED 10mA/DIV 10mA/DIV 10ms/DIV 0.1ms/DIV FIGURE 14. START-UP FIGURE 15. SHUT-DOWN ILED=15mA 2V VCNTL 1V VO ILED 14.2V 12.9V IL 30mA VLX 10V/DIV ∆VO 50mV/DIV 15mA 20ms/DIV FIGURE 16. TRANSIENT RESPONSE 8 10mV/DIV ∆VIN 100mA/DIV 1µs/DIV FIGURE 17. CONTINUOUS CONDUCTION MODE EL7513 Waveforms (Continued) All performance curves and waveforms are taken with C1 = 4.7µF, C2 = 1µF, C3 = 0.1µF, L = 33µF, VIN = 3.3V, VCNTL = 1V, R1 = 5Ω, 4 LEDs in a series; unless otherwise specified. VCTRL=0.34V, ILED=5mA ∆VIN 10mV/DIV VO (5V/DIV) IL 100mA/DIV VLX 10V/DIV ∆VO 50mV/DIV VCOMP (1V/DIV) 1µs/DIV FIGURE 18. DISCONTINUOUS CONDUCTION MODE Detailed Description The EL7513 is a constant current boost regulator specially designed for driving white LEDs. It can drive up to 4 LEDs in series or 12 LEDs in parallel/series configuration and achieves efficiency up to 91%. The brightness of the LEDs is adjusted through a voltage level on the CNTL pin. When the level falls below 0.1V, the chip goes into shut-down mode and consumes less than 1µA of current for VIN less than 5.5V. Steady-State Operation EL7513 is operated in constant frequency PWM. The switching is around 1MHz. Depending on the input voltage, the inductance, the type of LEDs driven, and the LED’s current, the converter operates at either continuous conduction mode or discontinuous conduction mode (see waveforms). Both are normal. Brightness Control LED’s current is controlled by the voltage level on CNTL pin (VCNTL). This voltage can be either a DC or a PWM signal with frequency less than 200Hz (for C3=4700pF). When a higher frequency PWM is used, an RC filter is recommended before the CNTL pin (see Figure 20). FIGURE 19. OVER VOLTAGE PROTECTION (LED DISCONNECTED) The relationship between the LED current and CNTL voltage level is as follows: V CNTL I LED = ---------------------------13.33 × R 1 When R1 is 5Ω, 1V of VCNTL conveniently sets ILED to 15mA. The range of VCNTL is 250mV to 5.5V. Shut-Down When VCNTL is less than 100mV, the converter is in shutdown mode. The max current consumed by the chip is less than 1µA for VIN less than 5.5V. Over-Voltage Protection When an LED string is disconnected from the output, VO will continue to rise because of no current feedback. When VO reaches 18V (nominal), the chip will shut down. The output voltage will drop. When VO drops below 16V (nominal), the chip will boost output voltage again until it reaches 18V. This hiccough continues until LED is applied or converter is shut down. When designing the converter, caution should be taken to ensure the highest operating LED voltage does not exceed 17V, the minimum shut-down voltage. There is no external component required for this function. Component Selection PWM SIGNAL 100K CNTL 0.1µF COMP FIGURE 20. PWM BRIGHTNESS CONTROL 9 The input and output capacitors are not very important for the converter to operate normally. The input capacitance is normally 0.22µF - 4.7µF and output capacitance 0.22µF - 1µF. Higher capacitance is allowed to reduce the voltage/current ripple, but at added cost. Use X5R or X7R type (for its good temperature characteristics) of ceramic capacitors with correct voltage rating and maximum height. EL7513 When choosing an inductor, make sure the inductor can handle the average and peak currents giving by following formulas (80% efficiency assumed): IO × VO I LAVG = ----------------------0.8 × V IN I DRMS = White LED Connections V IN × ( V O – V IN ) ∆I L = -------------------------------------------L × VO × FS One leg of LEDs connected in series will ensure the uniformity of the brightness. 18V maximum voltage enables 4 LEDs can be placed in series. where: • ∆IL is the peak-to-peak inductor current ripple in Ampere • L inductance in µH • FS switching frequency, typical 1MHz A wide range of inductance (6.8µH - 68µH) can be used for the converter to function correctly. For the same series of inductors, the lower inductance has lower DC resistance (DCR), which has less conducting loss. But the ripple current is bigger, which generates more RMS current loss. Figure 11 shows the efficiency of the demo board under different inductance for a specific series of inductor. For optimal efficiency in an application, it is a good exercise to check several adjacent inductance values of your preferred series of inductors. For the same inductance, higher overall efficiency can be obtained by using lower DCR inductor. EFFICIENCY (%) EFFICIENCY vs IO L=22µH L=33µH L=15µH PCB Layout Considerations The layout is very important for the converter to function properly. Power Ground ( ) and Signal Ground ( ) should be separated to ensure the high pulse current in the power ground does not interference with the sensitive signals connected to Signal Ground. Both grounds should only be connected at one point right at the chip. The heavy current paths (VIN-L-LX pin-PGND, and VIN-L-D-C2-PGND) should be as short as possible. The trace connected to the CS pin is most important. The current sense resister R1 should be very close to the pin When the trace is long, use a small filter capacitor close to the CS pin. The demo board is a good example of layout based on the principle. Please refer to the EL7513 Application Brief for the layout. 81 L=10µH 79 However, placing LEDs into series/parallel connection can give higher efficiency as shown in the efficiency curves. One of the ways to ensure the brightness uniformity is to prescreen the LEDs. The heat of the IC is mainly dissipated through the PGND pin. Maximizing the copper area around the plane is preferable. In addition, a solid ground plane is always helpful for the EMI performance. VIN=3.3V FOR DIFFERENT L 83 77 I LAVG × I O Ensure the diode's ratings exceed these current requirements. 1 I LPK = I LAVG + --- × ∆I L 2 85 The diode should be Schottky type with minimum reverse voltage of 20V. The diode's peak current is the same as inductor's peak current, the average current is IO, and RMS current is: L=Coilcraft LPO1704 SERIES 1mm HEIGHT 5 10 15 20 25 30 IO (mA) FIGURE 21. EFFICIENCY OF DIFFERENT INDUCTANCE (4 LEDs IN A SERIES) All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 10 EL7513 Package Outline Drawing NOTE: The package drawing shown here may not be the latest version. To check the latest revision, please refer to the Intersil website at <http://www.intersil.com/design/packages/index.asp> 11 EL7513 Package Outline Drawing NOTE: The package drawing shown here may not be the latest version. To check the latest revision, please refer to the Intersil website at <http://www.intersil.com/design/packages/index.asp> 12