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| SEMICONDUCTOR TECHNICAL DATA 1X/1. 5X Fractional Charge Pump for White LED Driver with 32step Dimming Control. 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. Features KAC3304DU Analog CMOS Integrated Circuits A B C A F H D Pin 1 E Top View Bottom View DIM K MILLIMETERS 1x/1.5x dual charge pump modes with auto detection. Excellent Power Efficiency. (more than 92% of PMAX) LED current matching of 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] 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. 1MHz switching frequency. Small UDFN-12A Package [3 3mm , t=0.5mm] L4 EN C1P C1N VOUT 2 Side View A B C D E F G H I J K _ 3.0 + 0.050 _ 2.4 + 0.030 2.250 Ref _ 0.230 + 0.030 _ 0.45 + 0.030 _ 1.700 + 0.030 _ 0.42 +0.050 0.300 45 Max 0.05 _ 0.203 + 0.008 _ 0.50 + 0.050 I UDFN-12A Pin Configuration Applications Cellular phones, Smart Phones, PDA, Digital Cameras, Camcorders. MP3 player and other handheld devices with color displays J L3 L2 L1 KAC3304DU GND VIN C2N Typical operating Circuit C2P Top View L4 EN L3 L2 L1 GND VIN C2N 1F Batt EN C1P 1F C1N L3 L2 L1 GND L4 EN C1P C1N VOUT C2P VOUT 1F C2P VIN C2N 1F Bottom View 2009. 2. 25 Revision No : 3 G 1/7 KAC3304DU Block Diagram C1P C1N C2P C2N VIN Charge Pump (1 /1.5 ) Soft-Start VOUT OVD Mode Controller OSC (1MHz) Error Amp Current Limit Thermal Protect VREF D/A Converter Min. Vol. Selector EN Single Wire Interface 5Bit Data LED1 LED2 LED3 LED4 GND Pin Descriptions Pin 1 2 3 4 5 6 7 8 9 10 11 12 Name L4 EN C1P C1N VOUT C2P C2N VIN GND L1 L2 L3 Sinking current input for LED4 Chip enable input. (Shutdown to Low state) Positive terminal of switched capacitor 1 Negative terminal of switched capacitor 1 Charge pump output Positive terminal of switched capacitor 2 Negative terminal of switched capacitor 2 Power supply voltage Input Ground Sinking current input for LED1 Sinking current input for LED2 Sinking current input for LED3 Function 2009. 2. 25 Revision No : 3 2/7 KAC3304DU AbsoluteMaximum Ratings Characteristics Input Supply Voltage Input Pin Maximum Power Dissipation. (@Ta=25 Thermal Resistance[QFN-16] Operating Ambient Junction Temperature Range Storage Temperature Range Lead Temperature Symbol VIN DIM, EN PD JA Rating -0.3 to +6.0 -0.3 to (VIN+0.2) 1.6 78.12 -40 to + 85 -40 to + 150 -55 to + 150 265 Units V V W /W Ta Tj Tstg TLEAD Electrical Characteristics (Ta=-40 to 85 , 2.7V< VIN < 5.5V, C1=C2=1.0 . unless otherwise noted.) (note 1) Parameter Input Supply Voltage Maximum LED sink current Quiescent current Power-down Current ILED Accuracy ILED Matching between any other ILED LED regulation Voltage Oscillator Frequency Maximum Output Current Symbol VIN ILED IQ IPD ILED_ACC ILED_MAT VLED FOSC IOUT ILIMIT TSD VOVP VHTY_OVP VEN_H VEN_L 2.5V Short Condition in VOUT Without Softstart. (Note 2) 40 Hysteresis 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 Soft Start 21mA 20mA 19mA 22mA 21mA 18mA 2.0mA 1.5mA 1.0mA Shut Down 0.5mA Shut Down LED Current Level Parameter Digital input voltage Digital input Current Start Time Stop Time EN High Time EN Low Time Rising Time Falling Time Filtered Noise Width Symbol VIL VIH IEN tEN_ON tEN_OFF tH tL tr tf tnoise Min 1.6 -0.2 300 2.5 7 6 Typ Max 0.4 0.2 1000 100 100 0.1 S S S S nS nS S Units V V Step 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Current[mA] 22 21 20 19 18 17 16 15 14 13 12 11 10 9.5 9.0 8.5 Step 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Current[mA] 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 tH tEN_ON EN Siganl tL tf tEN_OFF tr tNOISE Noise tNOISE 2009. 2. 25 Revision No : 3 6/7 KAC3304DU LED Current vs. Dimming Step 25 1.8 Quiesecent Current vs Temp Quiesecent Current (mA) 0 5 10 15 20 25 30 35 20 1.5 1.2 0.9 0.6 0.3 0.0 -50 0 50 100 150 LED Current (mA) 15 10 5 0 Step Temperature ( C ) LED Current vs Temp 26 1.8 1.5 LED 4 22 LED 1 LED 2 20 LED 3 Freg vs Temp 24 LED Current (mA) Frequency (MHz) 1.2 0.9 0.6 0.3 0.0 18 16 -50 0 50 100 150 -50 0 50 100 150 Temperature ( C ) Temperature ( C ) VOUT vs Temp 4.0 3.5 3.0 VOUT (V) 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 |
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