SEMICONDUCTOR KAB3403T/DN TECHNICAL DATA BICD LINEAR INTEGRATED CIRCUIT White LED Step-Up Converter E K 6 2 5 3 4 DIM A B C D E F 1 G B G K F G D A The KAB3403T/DN 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. KAB3403T/DN is available in a extremely low profile & small TS-6 package. A 10 H inductor is sufficient for most application. FEATURES Inherently Matched LED Current. Built in a open circuits protection for the LEDs fail. L C High Efficiency : 87% (max.) I Drives Up to Five LEDs MILLIMETERS _ 0.2 2.9 + 1.6+0.2/-0.1 _ 0.05 0.70 + _ 0.1 0.4 + 2.8+0.2/-0.3 _ 0.2 1.9 + 0.95 H I _ 0.05 0.16 + 0.00-0.10 J 0.25+0.25/-0.15 K L 0.60 0.55 H J J Built in a N-channel MOSFET Switch. Fast 1.1MHz(typ.) Switching Frequency. Wide Dimming control range : 12%~100%. Automatic Soft-Start TS6 Bulit in OVD (Over voltage protection.) Extremely low height & small Packaging. APPLICATIONS A Celluar Phones B Smart Phones A Digital Cameras E PDAs G F MP3 Players, Color Displays I H J C Marking 6 Type Name 403 Type Name 5 4 MILLIMETERS _ 0.10 2.00 + _ 0.10 1.60 + _ 0.05 0.30 + 0.65 Typ _ 0.10 1.00 + _ 0.10 0.25 + Φ 0.25 _ 0.05 0.75 + 0.0 + 0.05 0.20 Ref 403 Lot No. TDFN-6 1 KAB3403DN 2007. 2. 26 Lot No. DIM A B C D E F G H I J D 2 3 KAB3403T Revision No : 0 1/7 KAB3403T/DN TYPICAL APPLICATION CONVERSION EFFICIENCY L1 4.7µH ~ 22µH D1 VOUT VIN 90 LED1 VCC 85 SW EFFICIENCY (%) C1 1µF LED2 OVD C2 1µF LED3 KAB3403T/DN LED4 ON OFF CTL Shutdown and Dimming control FB VFB GND 80 75 70 R1 16Ω 3.0V 3.6V 4.3V 5.0V 65 60 0 5 15 10 20 25 30 35 LOAD CURRENT (mA) BLOCK DIAGRAM VCC SW I sens Comparator R Q OVER VOLTAGE DETECTION Driver S Ramp Generator OVD 1.1MHz Oscillator GND Soft Start FB Error Amp CTL Reference Generator Vref (320mV) Dimming Shutdown figure 2. KAB3403T/DN Block Diagram PIN FUNCTIONS NO. SYMBOL FUNCTION AND CONNECTION. KAB3403T KAB3403DN 6 1 VCC Input supply pin. Must be locally bypassed. 5 2 GND Ground pin. Connect directly to local ground plane, 4 3 FB Feedback pin. Reference voltage is 320mV. Connect cathode of lowest LED and resistor here. 3 4 SW Switch pin. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI. 2 5 OVD 1 6 CTL Over output voltage detect pin. Connect cathode of schottky diode and anode of highest LED. Control pin : Shutdown or dimming control. Connect external enable or dimming circuits. Shutdown mode (IF = 0) : VCTL<1.0V Dimming control mode : (IF = 12% ~ 100%, depend on VCTL) 2007. 2. 26 Revision No : 0 2/7 KAB3403T/DN MAXIMUM RATINGS (Ta=25 ) CHARACTERISTICS 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 -55 ~ 150 Tj 150 Maximum Junction temperature RECOMMENDED OPERATING CONDITIONS (Topr=-40~85 CHARACTERISTICS Input Voltage CTL pin voltage for full LED current ) SYMBOL CONDITION MIN. TYP. MAX. UNIT VCC - 2.7 - 5.5 V 2.7 - - V - - 0.5 V - 20 - 2 - - VCTL H VCC=3.0V CTL pin voltage to shutdown chip LED Current VCTL L VCC=3.6V, RSENSE=16 , IF CTL Response Delay Topr =25 , Five LED Tpd CTL (When Power ON.) ELECTRICAL CHARACTERISTIC (Topr=-40~85 , VCC=2.7~5.5V, RSENSE=16 CHARACTERISTICS - , unless otherwise noted.) SYMBOL CONDITION MIN. TYP. MAX. UNIT Input Voltage VCC - 2.7 - 5.5 V - 0.9 1.5 ICC VCC = 3.6V, VCTL=3.6V Supply Current VCTL = 0V - 0.5 1 304 320 336 - 5 10 0.77 1.1 1.43 - 400 - Feedback Voltage VFB VCC=VCTL=3.0V, Topr = 25 , L =4.7 H CTL Pin Bias Current ICTL VCC = 3.0V, VCTL = 3.0V Switching Frequency fOSC VCTL = 3.0V Switching Pin Current IO(SW) Switch Leak Current IOZ(SW) - - 0.5 1 OVD Pin Voltage VOVD - 19 21 23 - 0.5 1 25 - - V 2.7 - - V - - 0.5 V OVD Pin Leak Current IOZ(OVD) Switching Pin OVP VO(SW) CTL pin voltage for Full LED Current VCTL H CTL pin voltage to shutdown Chip VCTL L VOVD = 18V VCC = 3.0V Feedback Bias Current IFB - - 0.5 1 Maximum Duty Cycle Dmax - 85 90 - 2007. 2. 26 Revision No : 0 V % 3/7 KAB3403T/DN Inductor Section The KAB3403T/DN will then switch at a high duty cycle resulting comparision of different value inductors help you design your in a high output voltage. But Internal Over Voltage Protection application circuits. Circuits prevent output voltage ascending over OVD pin EFFICIENCY (%) A 10uH inductor is sufficient for most application. The efficiency 90 88 VIN=3.6, 4LED Inductor=Murata 86 84 82 80 78 76 74 72 70 68 66 64 62 60 0 5 15 20 10 voltage(19V ~ 23V 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 check connect of OVD pin to LED anode.(see Fig 5) [Recommended Zener diode : KDZ3.0V] L1 4.7µH ~ 22µH D1 VIN LED1 10µH 4.7µH VCC SW LED2 OVD 25 30 35 LOAD CURRENT (mA) C2 1µF LED3 KAB3403T/DN LED4 Figure3. Efficiency Comparison of different value inductors CTL FB GND C1 1µF Inductor Section R1 16Ω A 1uF input capacitor and output capacitor above 1uF are sufficient for most KAB3403T/DN application. Diode Selection Figure4. 4LEDs driver with Open-circuit protection. For Diode Selection, both forward voltage drop and diode L1 4.7µH~22µH capacitance need to be considered. Schottky diodes with higher current ratings usually have lower forward voltage and larger diode D1 VIN LED1 VCC schottky diode rated at 100mA to 200mA is sufficient for most DZ capacitance, which can cause significant switching losses. A SW LED3 OVD KAB3403T/DN applications. LED2 LED4 30 200 mA KDR412 20 500 mA 0.5V(max) at 500 mA 2 0.30 1.60 1.20 1.60 1.20 LED6 FB GND C1 1µF R1 16Ω 0.30 KDR720E 0.5V(max) at 200 mA LED5 CTL 2 0.6V (max) at 200 mA C2 1µF 2.50 1.70 Figure5. 6LEDs driver with Open-circuit protection. 0.30 200 mA 0.80 1 30 KAB3403T/DN Package 0.80 1 KDR730E Voltage Drop (V) 1.25 Part No. Reverse Forward Voltage (V) Current (mA) Table1. Recommended Schottky Diode 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 Figure 1). The feedback reference is 320mV. The LED current is 320mV/RSENSE . The tolerance of LED Current is depends on tolerance of RSENSE and feedback reference. 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. 2007. 2. 26 Revision No : 0 1. Using a DC Voltage to CTL pin VCTL Description 0V~0.5V 1V~2.5V VCTL>2.5V UNIT Rate Of the LED Current 0 25 ~ 100 100 % Example : RSENSE = 16 0 5 ~ 20 20 mA Table 2 CTL pin Voltage vs ILED 4/7 KAB3403T/DN 4. Using a Logic Signal to FB pin. L1 4.7µH ~ 22µH D1 For application that need to adjust the LED current in discrete VIN steps. A logic signal can be used as shown in Figure 9. VCC LED1 SW OVD C1 1µF L1 4.7µH ~ 22µH LED2 C2 1µF LED3 KAB3403T/DN LED1 LED4 DC CTL D1 VIN VCC FB SW LED2 OVD GND R1 16Ω C2 1µF LED3 KAB3403T/DN LED4 CTL C1 1µF GND FB LOGIC Rsence Figure6. Using a DC Signal to CTL pin. R1 KTK5132V 2. Using a filtered PWM Signal to CTL pin. The filtered PWM signal can be considered as an adjustable DC voltage. It can be used to replace the variable DC Voltage source Figure9. Using a Logic Signal to FB pin. in dimming control. The circuit is shown in Figure 7 L1 4.7µH ~ 22µH D1 VIN LED1 C1 1µF VCC SW LED2 OVD C2 1µF LED3 KAB3403T/DN R1 15kΩ LED4 CTL FB Rsence PWM Signal GND C3 1µF Figure7. Using a filtered PWM Signal to CTL pin. 3. Using a DC Voltage to FB pin. The dimming control using a DC control voltage to FB pin of the KAB3403T/DN is shown in Figure. The LED current can be varied applying a DC voltage to the FB pin. The voltage can come from a filtered PWM signal. It can be used to replace the variable DC voltage source in dimming control. L1 4.7µH ~ 22µH D1 VIN LED1 VCC SW OVD KAB3403T/DN 2007. 2. 26 C2 1µF LED3 LED4 CTL GND FB R1 R2 Revision No : 0 Rsence C1 1µF LED2 5/7 KAB3403T/DN VFB vs VCTL VFB vs Duty 350 350 300 300 250 250 VFB (mV) VFB (mV) VCC = 3.6V 200 150 150 100 100 50 50 0 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0 10 20 30 40 50 60 70 80 90 100 110 VCTL (V) Duty (%) Switching Frequency vs VIN VFB vs VIN 1.5 350 1.4 1.3 300 1.2 VFB (mV) Switching Frequency (MHz) 200 1.1 1.0 0.9 250 200 0.8 0.7 150 0.6 0.5 2.5 3.0 3.5 4.0 4.5 5.5 100 2.0 5.0 2.5 3.0 3.5 4.0 4.5 VIN (V) VIN (V) Inrush Current Efficicncy vs Temperature VIN=3.6V ILED=20µA 5.0 95 EN 90 2V/Div IIN 100mA/Div Efficicncy (%) 5V/Div VOUT Time (40µs/Div) 5.5 VIN=4.3V 85 VIN=3.6V 80 VIN=3.0V 75 70 65 60 55 50 -60 -10 40 90 140 Temperature ( C) 2007. 2. 26 Revision No : 0 6/7 KAB3403T/DN Quiescent Current vs Temperature Switching Frequency vs Temperature 500 1.6 V IN=4.3V 400 1.4 V IN=3.6V VIN=2.7V 1.2 ICC (µA) Switching Frequency (MHz) 1.8 1.0 0.8 300 200 0.6 0.4 100 0.2 0 -50 0 -50 0 100 50 -10 Temperature ( C) 30 70 110 Temperature ( C) APPLICATION CIRCUIT DC-DC Converter L1 10µH VIN VIN EFFICIENCY D1 KDR730E 16V/20mA SW COUT 1µF OVD CTL FB GND CIN 1µF VCC R2 740k FB R3 15k EFFICIENCY (%) 100 80 60 40 20 3.2V 3.6V 4.2V 0 0 10 20 30 40 50 LOAD CURRENT (mA) 2007. 2. 26 Revision No : 0 7/7