SEMICONDUCTOR KAC3304DU TECHNICAL DATA Analog CMOS Integrated Circuits 1X/1. 5X Fractional Charge Pump for White LED Driver with 32step Dimming Control. B C F H G The KAC3304DU is low noise constant frequency charge pump DC/DC converter specially designed to drive up to four white LEDs on 32step dimming control. Dual (1x/1.5x) Modes and low dropout voltage of LED driver maximize efficiency for the white LED application over full Li-ion battery input range. Various kinds of protection circuits protect your system from every undesirable output condition. A A D Pin 1 Bottom View DIM MILLIMETERS A B C D E F G H I J K _ 0.050 3.0 + _ 0.030 2.4 + 2.250 Ref _ 0.030 0.230 + _ 0.030 0.45 + _ 0.030 1.700 + _0.050 0.42 + 0.300 45 Max 0.05 _ 0.008 0.203 + _ 0.050 0.50 + I K Features J 1x/1.5x dual charge pump modes with auto detection. Excellent Power Efficiency. (more than 92% of PMAX) LED current matching of E Top View Side View 2%.(Typ.) Power-down current below 1 A.(max.) Drives up to 4 LED’s on 32step dimming control. Up to 22mA/LED current capability. [VIN > 3.1V] Up to 15mA/LED current capability. [VIN > 2.7V] Strong to ESD. [MM:>200V, HBM:>2000V] UDFN-12A Low input ripple and EMI. Fast serial dimming control. 2.7V to 5.5V input voltage range. Output over-voltage protection. Thermal shutdown protection. Output over-current protection. Soft start limits Inrush current. Automatic soft-start protects IC from output short. Pin Configuration 1MHz switching frequency. Small UDFN-12A Package [3 2 3mm , t=0.5mm] Applications Cellular phones, Smart Phones, PDA, Digital Cameras, Camcorders. MP3 player and other handheld devices with color displays L4 L3 EN L2 C1P C1N Typical operating Circuit L1 KAC3304DU GND VOUT VIN C2P C2N Top View EN L4 L3 EN L2 L3 L4 C1P L1 L2 EN C1N GND L1 C1P GND C1N VIN VOUT C2N C2P 1µF 1µF VOUT VIN C2P C2N 1µF 2009. 2. 25 Revision No : 3 1µF Batt Bottom View 1/7 KAC3304DU Block Diagram C1P VIN C1N C2P VOUT Charge Pump (1 /1.5 ) Soft-Start OSC (1MHz) Mode Controller Current Limit Single Wire Interface 5Bit Data OVD Error Amp Thermal Protect EN C2N Min. Vol. Selector VREF D/A Converter LED1 LED2 LED3 LED4 GND Pin Descriptions 2009. 2. 25 Pin Name 1 L4 Sinking current input for LED4 2 EN Chip enable input. (Shutdown to Low state) 3 C1P Positive terminal of switched capacitor 1 4 C1N Negative terminal of switched capacitor 1 5 VOUT Charge pump output 6 C2P Positive terminal of switched capacitor 2 7 C2N Negative terminal of switched capacitor 2 8 VIN Power supply voltage Input 9 GND 10 L1 Sinking current input for LED1 11 L2 Sinking current input for LED2 12 L3 Sinking current input for LED3 Revision No : 3 Function Ground 2/7 KAC3304DU AbsoluteMaximum Ratings Characteristics Input Supply Voltage Input Pin Maximum Power Dissipation. (@Ta=25 Thermal Resistance[QFN-16] Symbol Rating Units VIN -0.3 to +6.0 V DIM, EN -0.3 to (VIN+0.2) V PD 1.6 W 78.12 JA Operating Ambient Ta -40 to + 85 Junction Temperature Range Tj -40 to + 150 Storage Temperature Range Tstg -55 to + 150 TLEAD 265 Lead Temperature /W Electrical Characteristics (Ta=-40 to 85 , 2.7V< VIN < 5.5V, C1=C2=1.0 . unless otherwise noted.) (note 1) Parameter Symbol Conditions Min Typ Max Units Input Supply Voltage VIN - 2.7 - 5.5 V ILED VIN>2.7V - 15 - mA Maximum LED sink current VIN>3.1V - 22 - mA mA Quiescent current IQ No output load - 1.0 3.0 Power-down Current IPD VEN=Low - 0.1 1 ILED Accuracy ILED_ACC VIN=4.2V, @ILED=22mA - ±3 - % ILED Matching between any other ILED ILED_MAT VIN=4.2V, @ILED=22mA - ±2 - % 75 120 - mV 0.7 1 1.3 MHz LED regulation Voltage VLED Oscillator Frequency FOSC Maximum Output Current IOUT ILIMIT Input Current Limit TSD Thermal Shutdown Threshold 2.5V<VIN<5.5V VIN>3.1V, VOUT 3.8V 80 - - mA VIN>2.7V, VOUT 3.5V 60 - - mA Short Condition in VOUT Without Softstart. (Note 2) - 280 600 mA 40 - 150 - Hysteresis VOVP - - 5.5 6.0 V Hysteresis of VOVP VHTY_OVP - - 0.4 - V Enable Logic High VEN_H - 1.6 - - V Enable Logic Low VEN_L - - - 0.4 V Over-Voltage Protect Note 1) Specifications to -40 are guaranteed by design and not production tested. Note 2) This is occurred when Pin of LED is shorted to GND, or there are ohmic short VOUT to GND 2009. 2. 25 Revision No : 3 3/7 KAC3304DU Application Information Output Regulation KAC3304DU maintains constant LED brightness even at very low battery voltage. For example, at 2.7V of the battery voltage KAC3304DU can maintain constant LED bright above 20mA. For better efficiency KAC3304DU will be kept in 1x mode unless lowest voltage of the LED1~LED4 goes under the 75mV. Constant switching frequency & optimized duty make low input and output ripple at the 1.5x mode. Of course, KAC3304DU has almost no output ripple at the 1x mode. Shutdown (Enable=Low) When voltage of the ENABLE pin goes under 0.4V over then 2ms, KAC3304DU enter the shutdown mode where input current go to zero and there are no current between output capacitors and transfer capacitor. Soft-Start KAC3304DU has its original soft-start function to limit inrush current at turn on. KAC3304DU charges transfer capacitors and output capacitor with a constant input current until output voltage goes to the value of (1.4 VIN). If output voltage reached the value of (1.4 VIN) or over-voltage protection circuit is activated, LED current start to flow. But input current remains to zero until output voltage goes down to usual output operating voltage from the discharge of LED current. At the every turn on the ENABLE and output voltage less than 25% of the input voltage, soft-start sequence is introduced for the safety. Short protection (various short mode) 1) Short VOUT pin to GND pin: If output is shorted to ground, output current is limited by the soft-start which is repeated until VOUT remains under 25% of VIN. 2) Short LED pin to GND pin: If this occurs at the soft-start-mode or shutdown state, KAC3304DU stays at soft-start-mode. Else this is done during operating, the output current is limited by the current-limit-circuitry. 3) Short VOUT pin to LED pin(shorted LED) : There are no change but shorted LED doesn t work. Open protection If more than one LED is opened, output voltage is limited by over-voltage-protect circuitry. But, other LEDs work continuously without change of the brightness. Current limit There could be variable short mode in the backlight system. For example, VOUT pin to GND or LED pin to GND or short of LEDs, etc. In these case, large current could be flow at the output pin. KAC3304DU are protected by the thermal shutdown” circuitry, but external elements might be damaged without current limit” circuitry. Current limit circuitry set you to ease to design safely. Over-voltage protection When a LED pin shorted to the ground or LED is opened itself, voltage of the LED terminal could be almost 0V without any concerning to the other conditions. In this case, output voltage might be raised over IC’s maximum ratings. And, then IC may be destroyed KAC3304DU maintains “over voltage protection” circuitry for the prohibiting output voltage over the maximum ratings. Thermal shutdown KAC3304DU includes a thermal shutdown circuit which makes IC shutdown at 150 (typ.) and recover after IC cools by approximately 40 . 2009. 2. 25 Revision No : 3 4/7 KAC3304DU Input Ripple For driving LED Current IC’s in mobile system, input ripple is more important than output ripple, because there are many other components which have input supply terminal from battery instead of the output terminal. KAC3304DU has very excellent input ripple characteristics. You can get better input ripple characteristics, by minimizing resistance from battery to the VIN pin. Unused LED When driving fewer than 4 LEDs, connect any unused LED pin to VIN. This makes the corresponding LED driver disable, then there is no current consumption through unused LED pin, so KAC3304DU maintains its efficiency. Flash or Large Current Drive KAC3304DU can be used Flash Driver when shorting pins of 4 LEDs as circuits. Be careful that RSET should be set not for the ILED but for the IFLASH (=ILED 4). LED Current Control & Dimming KAC3304DU don t need external RSET terminal for the LED Current control. You can easily set LED current up to 32step with FSC(Fast Serial Control) throgh Enable terminal. 2009. 2. 25 Revision No : 3 5/7 KAC3304DU FSC(Fast Serial Control) 1 2 3 4 5 29 30 31 32 33 2mS EN 22mA 21mA Soft Start 22mA 20mA 19mA 18mA 2.0mA 1.5mA 1.0mA Shut Down 21mA 0.5mA Shut Down LED Current Level Symbol Min Typ Max Units Step Current[mA] Step Current[mA] VIL - - 0.4 V 0 22 16 8.0 VIH 1.6 - - V 1 21 17 7.5 IEN -0.2 - 0.2 2 20 18 7.0 Start Time tEN_ON 300 - - S 3 19 19 6.5 Stop Time tEN_OFF 2.5 - - S 4 18 20 6.0 EN High Time tH 7 - - S 5 17 21 5.5 EN Low Time tL 6 - 1000 S 6 16 22 5.0 Rising Time tr - - 100 nS 7 15 23 4.5 Falling Time tf - - 100 nS 8 14 24 4.0 tnoise - - 0.1 S 9 13 25 3.5 10 12 26 3.0 11 11 27 2.5 12 10 28 2.0 13 9.5 29 1.5 14 9.0 30 1.0 15 8.5 31 0.5 Parameter Digital input voltage Digital input Current Filtered Noise Width tH tEN_ON EN Siganl tL tr tEN_OFF tf tNOISE Noise tNOISE 2009. 2. 25 Revision No : 3 6/7 KAC3304DU Quiesecent Current vs Temp LED Current vs. Dimming Step 1.8 Quiesecent Current (mA) 25 LED Current (mA) 20 15 10 5 1.5 1.2 0.9 0.6 0.3 0.0 0 0 5 10 15 20 25 30 35 -50 0 Step 100 150 100 150 Temperature ( C ) LED Current vs Temp Freg vs Temp 1.8 26 1.5 Frequency (MHz) 24 LED Current (mA) 50 LED 3 LED 4 22 LED 1 LED 2 20 18 1.2 0.9 0.6 0.3 16 0.0 -50 0 50 100 150 -50 0 50 Temperature ( C ) Temperature ( C ) VOUT vs Temp 4.0 3.5 VOUT (V) 3.0 2.5 2.0 1.5 1.0 0.5 0.0 -50 0 50 100 150 200 Temperature ( C ) 2009. 2. 25 Revision No : 3 7/7