tm TE CH Preliminary T6313A Low Noise, High Efficiency WhiteLED Charge Pump FEATURES GRNERAL DESCRIPTION • 4 Current Source Outputs • 20mA Full Scale Current for each LED • Power efficency up to 93% • 32 levels for brightness • 2 wires interface • Low Noise Constant Frequency Operation • High Accuracy Brightness Matching • White LED Backlighting • 0.5% LED current matching • Automatic Soft-Start • No External Inductors, Schottky, or Zener Diode and Resistor Required • 500KHz Switching Frequency (1MHz optional) • 2.7V to 5.5V supply voltage • Shutdown current is less 1uA • Temperature Range -40 to 85°C • 16-Pin QFN The T6313A is a charge pump DC/DC converter driving a constant current up to 20mA for each LED of total four LEDs. It is a high efficiency device that is up to 93%, and it would be a suitable driving device for LED back light application. The T6313A operates in a 1.5x charge pump mode based on input voltage from 2.7v to 5.5v. Operation frequency is at fixed high frequencies either 500KHz or 1MHz typically. It can drive 4 white LEDs connected in parallel and provides tightly matched regulated current to achieve uniformity of brightness in LCD backlighting applications. The T6313A uses two input pins to enable, disable, and set the LED drive current for one of 32 levels of brightness. Also has a built-in softstart circuitry to prevent excessive inrush current during start-up. A very low shutdown current feature and a low quiescent current will consume very little power and allow the device to operate in a very high efficiency. The T6313A is available in 16-pin QFN packages. Applications • Cellular Phones • Portable Communication Devices • Handheld devices • Digital Cameras • PDAs • LED/Display Back Light Driver • LEDs for Camera Flash PART NUMBER EXAMPLES PART NO. PACKAGE Marking T6313A-AF QFN 4mm X 4mm 6313 T6313A-BF QFN 3mm X 3mm 6313 TM Technology Inc. reserves the right P. 1 to change products or specifications without notice. Publication Date: JAN. 2006 Revision: C tm TE CH Preliminary T6313A PIN ARRANGEMENT(Top view) QFN- 4mm x 4mm AND 3mm x 3mm –16 D1 SET VIN EN 16 15 14 13 D2 1 12 GND D3 2 11 C2 - D4 3 10 C2+ NC 4 9 VOUT 5 6 7 8 NC C1+ C1 - NC PIN DESCRIPTION SYMBOL D2 D3 D4 N.C. N.C. C1+ C1N.C. VOUT C2+ C2GND EN VIN SET D1 Pin no. QFN-16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 DESCRIPTION Current source output 2 Current source output 3 Current source output 4 No Connect No Connect Flying capacitor 1 + terminal Flying capacitor 1 – terminal No Connect Charge pump output. Requires 1uF bypass capacitor to ground. Flying capacitor 2 + terminal Flying capacitor 2 – terminal Ground Enable T6313A signal, H:active, L:power down Input power supply. Requires 1uF bypass capacitor to ground. Set brightness level Current source output 1.Required reference current source. TM Technology Inc. reserves the right P. 2 to change products or specifications without notice. Publication Date: JAN. 2006 Revision:C tm TE CH Preliminary T6313A BLOCK DIAGRAM C1+ C1- C2+ C2- 1.5X Charge Pump 1MHz/500K Oscillator EN SET Interface Control Decoder VOUT Soft Start Current Drive D1 D2 D3 D4 Fig-1 TM Technology Inc. reserves the right P. 3 to change products or specifications without notice. Publication Date: JAN. 2006 Revision:C tm TE CH Preliminary T6313A ABSOLUTE MAXIMUM RATINGS (TA = 25°°C unless otherwise noted) IN, OUT, EN to GND …………………-0.3V to 6V LED1 ~4 to GND …………………-0.3V to (Vin+0.3V) Operating Temperature …………………-40 to 85°C Storage Temperature …………………-40 to 150°C Electrical Characteristics (TA = -40 to 85°C unless otherwise noted. Typical values are at TA =25°C, VIN =3.5V) Symbol VIN Description Conditions Input Voltage 2.7 VEN (low) Enable threshold Low VIN=2.7 to 5.5V VEN (high) Enable threshold High VIN=2.7 to 5.5V VSET (low) Enable threshold Low VIN=2.7 to 5.5V VSET (high) Enable threshold High VIN=2.7 to 5.5V ICC Min. Typ. Max Unit 5.5 V 0.4 V 1.4 V 0.4 1.4 V V Operating Current Active, No Load Current Shutdown Supply Current EN=0 Output Current 3.2V ≤ VIN ≤ 5.5V, TA=25°C, All Outputs Max. Current Iout_m Current Matching between D1 and any other outputs VD1 : VDn=3.6V, VIN=3.3V IILEN EN input leakage VIN= 5.5V -1 1 uA IILset SET input leakage VIN= 5.5V -1 1 uA ISHDN Iout 1.3 18 20 2 mA 1 uA 22 mA 0.5 % tSS Soft start time 500 us tLO SET low time tOFF SET off time 350 tHI Minimum SET high time 50 ns η Efficiency VIN=3.5V, IOUT (total) =40mA 93 % fOSC Frequency Oscillator Free Running 1000/ 500 KHz 0.5 TM Technology Inc. reserves the right P. 4 to change products or specifications without notice. us 500 us Publication Date: JAN. 2006 Revision:C tm TE CH Preliminary T6313A Typical Operating Characteristics (VIN=+3.5V, CIN= COUT=C1=C2=1uF, TA=+25 ºC, unless otherwise noted.) TBD TM Technology Inc. reserves the right P. 5 to change products or specifications without notice. Publication Date: JAN. 2006 Revision:C tm TE CH Preliminary T6313A Functional Description The T6313A uses a fractional (x1.5) conversion charge pump to generate a voltage for the regulated current sinks. These current sinks are used to ensure a constant current for each LED. The charge pump can generate total 80 mA of output current, so each of the 4 LED outputs can be powered with up to 20 mA of current. The T6313A uses two wires to enable and set the LED currents. The EN pin is used to either enabling or disabling the T6313A. When EN is high, then the numbers of pulse shift from SET pin are valid and an internal counter counts up from 1 from the first rising edge of SET and increases by one when another rising edge of SET is shifted in. The outputs of the counter will map to 32 levels of LED current. Each level (code) is mapped to a different current, which is a defferent brightness (Fig-2 & Tabel1). Once the final clock cycle is input for the desired brightness level, the SET pin is held high to maintain the device output current at the programmed level. The device is disabled 350us after the SET pin transitions to a logic low state. A level will stay until EN goes low. T6313A is power down when EN goes low. After EN goes low then any pulse shifting from SET pin is invalid (Fig-3). I diode(mA) 25 20 15 10 5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 0 Code Fig - 2 TM Technology Inc. reserves the right P. 6 to change products or specifications without notice. Publication Date: JAN. 2006 Revision:C tm TE CH Preliminary T6313A Table1 : current level (mA) code 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 20mA max. 0.549 0.627 0.706 0.784 0.863 1.020 1.098 1.255 1.412 1.569 1.804 1.961 2.275 2.510 2.824 3.137 code 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 20mA max. 3.529 4.000 4.471 5.020 5.647 6.353 7.059 7.922 8.941 10.039 11.216 12.627 14.118 15.843 17.804 20.000 SET vs ILED IL E D 32 31 4 3 2 1 1 tO FF> 5 0 0 u s t H I> 5 0 n s 0 .5 u s < t L O < 7 5 u s C ode SET C ode 1 2 3 4 31 32 1 OFF EN S ta te Fig.-3 Enable / Disable / LED Brightness Level Set Data Input TM Technology Inc. reserves the right P. 7 to change products or specifications without notice. Publication Date: JAN. 2006 Revision:C tm TE CH Preliminary T6313A TYPICAL APPLICATION CIRCUITS SET SET EN EN V IN Battery C1- C1 1uF C2+ C2- C2 1uF C1+ D1 D2 D3 D4 C IN 1uF C OUT 1uF V OUT GND TM Technology Inc. reserves the right P. 8 to change products or specifications without notice. Publication Date: JAN. 2006 Revision:C tm TE CH Preliminary T6313A PACKAGE DIMENSIONS QFN3mm x 3mm-16 B ottom V iew Top View Pin-1 Index Pin-1 Index A1 13 B 16 1 12 A C D 4 9 8 5 G H C2 C1 Symbol A A1 B C C1 C2 D G H Min. 0.18 0.30 1.40 0.70 2.90 2.90 0 Dimension in mm Typ. 0.50(BSC) 0.23 0.40 1.50 0.20 0.75 3.00 3.00 0.02 Max. Min. 0.30 0.50 1.60 7.09 11.81 55.12 0.80 3.10 3.10 0.05 27.6 114.17 114.17 0 Dimension in mil Typ. 19.69 9.06 15.75 59.06 8.00 29.5 118.11 118.11 0.79 TM Technology Inc. reserves the right P. 9 to change products or specifications without notice. Max. 11.81 19.69 62.99 31.5 122.05 122.05 1.97 Publication Date: JAN. 2006 Revision:C tm TE CH Preliminary T6313A PACKAGE DIMENSIONS QFN4mm x 4mm-16 B ottom V iew Top View Pin-1 Index Pin-1 Index A1 13 B 16 B1 1 12 A C D 4 9 8 5 B2 G H C2 C1 Symbol A A1 B B1 B2 C C1 C2 D G H Min. 0.28 0.55 0.40 2.35 0.17 0.85 3.95 3.95 0.00 Dimension in mm Typ. 0.65(BSC) 0.33 0.60 0.45 2.28(REF) 2.40 0.20 0.90 4.00 4.00 0.12 Max. Min. 0.38 0.65 0.50 0.011 0.022 0.016 2.45 0.23 0.95 4.05 4.05 0.25 0.092 0.006 0.033 0.155 0.155 0.000 Dimension in inch Typ. 0.025(BSC) 0.013 0.024 0.018 0.090(REF) 0.094 0.008 0.035 0.157 0.157 0.005 TM Technology Inc. reserves the right P. 10 to change products or specifications without notice. Max. 0.015 0.026 0.020 0.096 0.009 0.037 0.159 0.159 0.009 Publication Date: JAN. 2006 Revision:C