SEMICONDUCTOR KIB3402F TECHNICAL DATA BICD LINEAR INTEGRATED CIRCUIT White LED Step-Up Converter The KIB3402F is a monolithic step-up DC/DC converter specifically designed to drive white LEDs with a constant current from Li-ion cell. Relative large 320mV feedback voltage & it’s high accuracy help you setting LED current with a external resistor. KIB3402F is available in a extremely low profile & small TS-6 package. A 4.7 H inductor is sufficient for most application. E K 6 2 5 3 4 DIM A B C D E F 1 G B G A K F G D FEATURES Inherently Matched LED Current. MILLIMETERS _ 0.05 2.9 + _ 0.05 1.6 + _ 0.05 0.7 + _ 0.05 0.4 + _ 0.07 2.8 + _ 0.05 1.9 + 0.95 _ 0.05 0.16 + _ 0.05 0.05 + MIN 0.21 _ 0.07 0.6 + H I K L L J Built in a open circuits protection for the LEDs fail. C High Efficiency : 85% (max.) Drives Up to four LEDs without external zener diode. I J J Drives Up to six LEDs with external zener diode. 0.4 H Built in a N-channel MOSFET Switch. Fast 1.1MHz(typ.) Switching Frequency. Uses Tiny 1mm Tall Inductors. Bulit in Thermal protection. TS6 Wide Dimming control range : 25%~100%. Extremely low height & small Packaging. Marking APPLICATIONS 6 Celluars Phones 5 4 Lot No. PDAs Type Name Digital Cameras 402 MP3 Players, Color Displays 1 2 3 TYPICAL APPLICATION L1 4.7 µH~10 µH CONVERSION EFFICIENCY D1 VIN 87.00 6 VCC SW LED1 85.00 OVD 2 LED3 KIB3402F ON OFF LED2 C2 1µF LED4 1 CTL FB 4 Shutdown and Dimming control GND 5 R1 21.5Ω EFFICIENCY (%) C1 1µF 3 83.00 81.00 79.00 Vin 3.0V 3.6V 4.3V 77.00 75.00 0 0 C1, C2 : X5R OR X7R DIELECTRIC D1 : KEC KDR730E/KDR720E (Low VF ) 5 10 15 20 25 LOAD CURRENT (mA) L1 : MURATA LQH32CN100K53L OR EQUIVALENT Figure1. 4Series White LED Driver in Thin TS6 2006. 4. 20 Revision No : 0 1/6 KIB3402F BLOCK DIAGRAM VCC SW 3 6 2 OVD + One Shot - + + OUT - + - VRef _ OUT One Shot + + Vth + - - OUT + _ - + 320mV CTL 1 ADC 5 GND 4 FB(Rsense) figure 2. KIB3402F Block Diagram MAXIMUM RATINGS (Ta=25 ) CHARATERISTICS SYMBOL RATING UNIT Input Voltage VCC -0.3 ~ 6.0 V Switching pin Voltage VSW -0.3 ~ 22 V OVD pin Voltage VOVD -0.3 ~ 22 V Operating temperature range Topr -40 ~ 85 Storage temperature range Tstg -40 ~ 150 Tj 150 Maximum Junction temperature RECOMMENDED OPERATING CONDITIONS (Topr=-40~85 CHARATERISTICS Input Voltage CTL pin voltage for full LED current ) SYMBOL CONDITION MIN. TYP. MAX. UNIT VCC - 2.8 - 5.5 V 2.7 - - V - - 0.5 V 33 - - - 20 - 2 - - VCTL H VCC=3.0V CTL pin voltage to shutdown chip VCTL L CTL pin input pulse width tPW(CTL) LED Current CTL Response Delay (When Power ON.) 2006. 4. 20 IF Tpd CTL Revision No : 0 Both Positive and Negative pulse VCC=3.6V, RSENSE=16 Topr =25 , Four LED - , 2/6 KIB3402F ELECTRICAL CHARACTERISTIC (Topr=-40~85 , VCC=2.8~5.5V, RSENSE=16 CHARATERISTICS , unless otherwise noted.) SYMBOL CONDITION MIN. TYP. MAX. UNIT Input Voltage VCC - 2.8 - 5.5 V ICC VCC = 3.6V, VCTL=3.6V - 0.9 1.5 Supply Current VCTL = 0V - 0.5 1 294 320 346 - 20 - 0.77 1.1 1.43 - 400 - - 0.7 1.5 Feedback Voltage VFB VCC=VCTL=3.0V, Topr = 25 , L =10 H CTL Pin Bias Current ICTL VCC = 3.0V, VCTL = 3.0V Switching Frequency fOSC VCTL = 3.0V Switching Pin Current IO(SW) RON Switch RDS(ON) IO(SW) 400 Switch Leak Current IOZ(SW) - - 0.5 1 OVD Pin Voltage VOVD - 16 20 22 IOZ(OVD) - - 0.5 1 Thermal Shutdown TSD - - 150 180 Switching Pin OVP VO(SW) - 25 - - V CTL pin voltage for Full LED Current VCTL H 2.7 - - V CTL pin voltage to shutdown Chip VCTL L - - 0.5 V OVD Pin Leak Current VCC = 3.0V Feedback Bias Current IFB - - 0.5 1 Maximum Duty Cycle Dmax - 85 90 - V % PIN FUNCTIONS NO. SYMBOL FUNCTION AND CONNECTION. Control pin : Shutdown or dimming control. Connect external enable or dimming circuits. Shutdown mode (IF = 0) : VCTL<1.0V 1 CTL Dimming control mode : (IF = 20% ~ 100%, depend on VCTL) 1.0V < VCTL < 2.5V, when VCTL is above 2.5V IF keep its maximum value(100%). Filtered PWM signal, above 33us of pulse width, can be used for dimming control. 2 OVD 3 SW Switch pin. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI. 4 FB Feedback pin. Reference voltage is 320mV. Connect cathode of lowest LED and resistor here. 5 GND Ground pin. Connect directly to local ground plane, 6 VCC Input supply pin. Must be locally bypassed. 2006. 4. 20 Over output voltage detect pin. Connect cathode of schottky diode and anode of highest LED. Revision No : 0 3/6 KIB3402F APPLICATION INFORMATION Inductor Selection A 4.7 H inductor is sufficient for most application. The efficiency comprison of different value inductors help you design your application circuits. 90.00 Vin=3.6V, 4LED Inductor=Murata 88.00 The KIB3402F will then switch at a high duty cycle resulting in a high output voltage, but Internal Over Voltage Protection Circuits prevent output voltage ascending over OVD pin voltage( 16V ~ 22V see Fig.4 ). This circuits is valid when driving up to 4 LEDs in series. But, when driving more than 4 LEDs in series, Normal output voltage could be over OVD pin voltage. In this case, zener diode can be used to limit output voltage, but check connection of OVD pin to VCC.(see Fig.5) EFFICIENCY (%) 86.00 L1 4.7 µH~10 µH 84.00 D1 VIN 82.00 80.00 6 78.00 VCC 3 SW 76.00 LED1 OVD 2 74.00 KIB3402F 10uH 70.00 5 10 15 20 LED4 1 CTL 25 FB 4 C1 1µF LOAD CURRENT (mA) GND 5 RSENSE 21.5Ω 0 C2 1µF LED3 4.7uH 72.00 LED2 Figure3. Efficiency Comaprison of different value inductors Capacitor Selection input capacitor and output capacitor above 1 A 1 sufficient for most KIB3402F application. Figure4. 4LEDs driver with Open-circuit protection. KDR412 20 500 mA 0.5V(max) at 500 mA 0.30 0.5V(max) at 200 mA 2 200 mA 0.30 30 1.60 1.20 2 KDR720E 6 3 SW VCC LED2 LED3 2 OVD KIB3402F LED4 C2 1µF LED5 LED6 FB 4 C1 1µF GND 5 R1 16Ω 1.60 1.20 0 2.50 1.70 0.30 0.6V (max) at 200 mA LED1 1 CTL 0.80 1 200 mA D1 VIN Package 0.80 1 30 Voltage Drop (V) 1.25 KDR730E Reverse Forward Voltage (V) Current (mA) L1 4.7 µH~10 µH DZ Diode Selection For Diode Selection, both forward voltage drop and diode capacitance need to be considered. Shottky diodes with higher current ratings usually have lower forward voltage and larger diode capacitance, which can cause significant switching losses. A schottky diode rated at 100 to 200 is sufficient for most KIB3402F applications. Part No. 0 are Figure5. 6LEDs driver with Open-circuit protection. Table 1. Recommended Schottky Diodes Dimming Control There are 4 different type of dimming control circuits: LED Current Control The LED current is controlled by the feedback resistor(RSENSE in 1. Using a DC Voltage to CTL pin. Figure 1). The feedback reference is 320 . VCTL The LED current is 320 /RSENSE. The tolerance of LED Current is Description UNIT depends on tolerance of RSENSE and feedback reference. 0V~0.5V 1V~2.5V VCTL>2.5V Open-Circuits Protection In the case of output open circuit, when LEDs are disconnected from the circuit or the LEDs fail, the feedback voltage will be zero. 2006. 4. 20 Revision No : 0 Rate Of the LED Current 0 25 ~ 100 100 % Example : RSENSE = 16 0 5 ~ 20 20 mA Table 2 CTL pin Voltage vs ILED 4/6 KIB3402F L1 4.7 µH~10 µH VIN C1 1µF D1 6 3 VCC SW Vsw 5V/Div LED1 LED2 OVD 2 DC C2 1µF LED3 KIB3402F VCTL 2V/Div LED4 1 CTL FB 4 RSENSE 21.5Ω GND 5 (A) 1kHz (2ms/Div) Figure 7. Using a PWM Signal to CTL pin. 0 3. Using a DC Voltage to FB pin. Figure6. Using a DC Signal to CTL pin. The dimming control using a DC control voltage to FB pin of the 2. Using a PWM Signal to CTL pin. KIB3402F is shown in Figure. The LED current can be varied With the PWM signal applied to the CTL pin, the KIB3402F is turned applying a DC voltage to the FB pin. The voltage can come from a on or off by the signal. Typical frequency range of the PWM signal is filtered PWM signal. It can be used to replace the variable DC 15kHz to 30kHz. Voltage source in dimming control. The switching waveforms of the CTL pin PWM control are shown in Figure 7(A) and 7(B) D1 L1 VIN D1 VIN C1 1µF 6 3 VCC SW 3 SW LED1 KIB3402F LED4 R1 1 CTL C2 1µF FB 4 GND C1 1µF LED4 5 R2 5 RSENSE 21.5Ω FB 4 GND 0 C2 1µF LED3 KIB3402F LED2 LED3 1 CTL LED2 OVD 2 LED1 OVD 2 PWM 6 VCC 0 RSENSE L1 4.7 µH~10 µH 0 DC 0 Figure8. Using DC Voltage to FB pin. 0 4. Using a Logic Signal to FB pin. For applications that need to adjust the LED current in discret steps, a logic signal can be used as shown in Figure 9. Vsw 5V/Div D1 L1 VIN VCTL 6 3 VCC SW LED1 LED2 2V/Div OVD 2 KIB3402F LED4 1 CTL (A) 1kHz (2ms/Div) C2 1uF LED3 FB 4 C1 1uF Rdim GND 5 KTK5132V LOGIC RSENSE 0 Figure9. Using a Logic Signal to FB pin. 2006. 4. 20 Revision No : 0 5/6 KIB3402F Efficicncy vs Temperature VFB vs VCTL 95 350 VFB 90 EFFICICNCY (%) 300 V FB (mV) 250 200 150 100 Vin=4.3V 85 Vin=3.6V 80 Vin=3.0V 75 70 65 60 50 55 0 50 0 1 2 3 4 5 -60 -10 40 V CTL (V) Temperature ( C) Switching Frequency vs Temperature Frequency vs Vcc SWITCHING FREQUENCY (MHz) 1.01 FREQUENCY (MHz) 1.00 0.99 0.98 0.97 0.96 0.95 0.94 0.93 0.92 0.91 1.5 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 2.5 3.5 4.5 5.5 -50 6.5 0 Vcc (V) Thermal Shut Down 500 400 350 Vin=4.3V 300 Vin=3.6V Vin=2.7V V FB (mV) Icc (µA) 300 100 50 Temperature ( C) Quiescent Current vs Temperature 400 140 90 200 250 200 150 100 100 50 0 -50 0 -10 30 TEMP ( C) 2006. 4. 20 Revision No : 0 70 110 105 115 125 135 145 155 165 175 185 TEMP ( C) 6/6