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| Preliminary RT9269 Tiny Package, High Efficiency, Constant Current LED Driver General Description The RT9269 is a compact, high efficient LED driver with high flexibility of application configurations in charge pump mode or in boost rectifier mode, delivering Tens of mA constant output current for driving 1~4 white LED's. The 0.25V low reference voltage minimized the power loss across the current-setting resistor. The wide applicable VDD range makes RT9269 suitable for 1 to 4 battery cell applications as well as being supplied with 2.5/3.3/5/6V system powers. The 500kHz high switching rate minimized the size of external components. Besides, the 17A low quiescent current together with high efficiency maintains long battery lifetime. The output current is set with 1 external resistor. And the chip enable (CE) pin can be used for tuning the LED brightness by controlling the ON/OFF duty with external clock. RT9269 is provided in SOT-26 package. Features 0.25V Low Reference Voltage 17A Quiescent (Switch-off) Supply Current Zero Shutdown Mode Supply Current 85% Efficiency 500kHz Fixed Switching Rate Tuning LED brightness with CE pin ON/OFF Duty Small SOT-26 Package Applications LED Module Hand Held Panel Compact Back Light Module Small Battery Charger Constant Current Source Pin Configurations Part Number RT9269CE (Plastic SOT-26) Pin Configurations TOP VIEW 6 5 4 Ordering Information RT9269 Package Type E : SOT-26 Operating Temperature Range C: Commercial Standard 1 2 3 1. 2. 3. 4. 5. 6. CE EXT GND LX VDD FB Marking Information For marking information, contact our sales representative directly or through a RichTek distributor located in your area, otherwise visit our website for detail. DS9269-01 March 2003 www.richtek.com 1 RT9269 Typical Application Circuit VIN C1 1 F VDD Preliminary C2 1 F EXT 0.25V R1 15 R2 15 C3 1 F RT9269 To VDD or Duty Control Brightness CE GND FB Fig. 1 RT9269 drives single or parallel LED's in charge pump configuration D1 VIN C1 1 F VDD EXT 0.25V R1 15 C2 1 F C3 1 F D2 RT9269 To VDD or Duty Control Brightness CE GND FB Fig. 2 RT9269 drives 2 series connected LED's in charge pump configuration VIN R1 1K C1 10 F L1 10 H ~ 100 H Q1 C2 1 F VDD RT9269 CE GND FB LX 0.25V C3 10 F To VDD or Duty Control Brightness R2 15 Fig. 3 RT9269 drives 2~4 series connected LED's in boost rectifier configuration Note: NICHIA NSCW100 is used for RT9269 LED parts. www.richtek.com DS9269-01 March 2003 2 Preliminary Pin Description Pin No. Pin Name 1 2 3 4 5 6 CE EXT GND LX VDD FB Pin Function Chip enable RT9269 gets into shutdown mode when CE pin set to low. Output pin for configuring charge pump or driving external NMOS Ground Pin for switching Input positive power pin of RT9269 Feedback input pin Internal reference voltage for the error amplifier is 0.25V. RT9269 Function Block Diagram VDD RT9269 EXT LX FB VDD 0.25 V R2 CE Q3 NMOS _ Loop Control Circuit Q1 NMOS R1 Over Temp. Detector + + + Shut Down GND DS9269-01 March 2003 www.richtek.com 3 RT9269 Absolute Maximum Ratings Supply Voltage LX Pin Switch Voltage Other I/O Pin Voltages LX Pin Switch Current EXT Pin Driver Current Power Dissipation, PD @ TA = 25C SOT-26 * Package Thermal Resistance SOT-26, JA Operating Junction Temperature Storage Temperature Range Preliminary - 0.3V to 7V - 0.3V to (VDD + 0.8V) - 0.3V to (VDD + 0.3V) 2.5A 200mA 0.25W 250C/W 125C - 65C ~ +150C Electrical Characteristics (VIN =3.3V, VDD set to 5V, Load Current = 0, TA = 25C, unless otherwise specified) Parameter Start-UP Voltage Operating VDD Range No Load Current I (VIN) Switch-off Current I (VDD) Shutdown Current I (VIN) Feedback Reference Voltage Switching Rate Maximum Duty LX ON Resistance Current Limit Setting EXT ON Resistance to VDD EXT ON Resistance to GND CE Pin Trip Level Temperature Stability for VREF Thermal Shutdown Thermal Shutdown Hysterises Ts TSD TSD ILIMIT Symbol VST VDD INO LOAD ISWITCH OFF IOFF VREF FS DMAX Test Conditions IL = 1mA VDD pin voltage VIN = 3.3V, VOUT = 5V VIN = 6V CE Pin = 0V, VIN = 6V Close Loop, VDD = 5V VDD = 5V VDD = 5V VDD = 5V VDD = 5V VDD = 5V VDD = 5V VDD = 5V ------0.4 ---Min -2 ---Typ 0.98 -30 17 0.1 0.25 500 75 0.4 500 5 5 0.8 50 165 10 ------1.2 ---Max 1.05 6.5 --1 Units V V A A A V kHz % mA V ppm/C C C www.richtek.com DS9269-01 March 2003 4 Preliminary Typical Operating Characteristics Efficiency vs. Input Voltage 89 85 84 RT9269 Efficiency vs. Vin 6 LEDs, L = 33 H 4 LEDs, L = 47 H 87 Efficiency (%) 85 Efficiency(%) 83 82 81 80 79 IOUT = 20 mA 83 IOUT = 20mA IOUT = 15 mA 81 IOUT = 15mA 79 2.5 3 3.5 4 4.5 5 5.5 6 3 3.5 4 4.5 5 5.5 6 Input Voltage (V) VIN(V) 600 500 Frequency vs. VDD 100 Efficiency vs. Input Voltage 90 IOUT = 20mA @ VIN > 3.8V Frequency(KHz) Efficiency (%) 400 300 200 100 0 0 1 2 3 80 70 IOUT = 15mA @ VIN > 3.6V 60 FB = GND, TA = 25C 50 6 Refer to Application Circuit Fig. 2 3.0 3.5 4.0 4.5 5.0 5.5 6.0 VDD (V) 4 5 Input Voltage (V) VFB vs. Ambient Temperature 256 254 100 90 80 Efficiency vs. Output Current Efficiency (%) 252 VFB (mV) 70 60 50 40 VIN = 4.2V VIN = 2.7V 250 248 246 244 -40 -20 0 20 40 60 80 VIN = 3.6V 30 20 0.1 1 10 100 Ambient Temperature (C) Output Current (mA) DS9269-01 March 2003 www.richtek.com 5 RT9269 Power ON Waveform Preliminary Power ON Waveform VIN = 2.5V for 4LEDs VIN VIN = 3.0V for 4LEDs VIN LX 200mA/DIV LX 200mA/DIV IIN IOUT 20mA/DIV Refer to Application Circuit Fig. 3 IIN IOUT 20mA/DIV Refer to Application Circuit Fig. 3 Time (2.5mS/DIV) Time (2.5mS/DIV) LX vs. Output Ripple Waveform VIN = 3.0V for 4LEDs LX vs. Output Ripple Waveform VIN = 2.5V for 4LEDs LX LX Output Output IOUT 20mA/DIV Refer to Application Circuit Fig. 3 IOUT 20mA/DIV Refer to Application Circuit Fig. 3 Time (500nS/DIV) Time (1S/DIV) Power Up Waveform VIN = 3.0V IOUT = 20mA VIN VIN VIN = 2.5V IOUT = 20mA Power Up Waveform LX LX CE 20mA/DIV IOUT Refer to Application Circuit Fig. 3 CE IOUT 20mA/DIV Refer to Application Circuit Fig. 3 Time (250S/DIV) Time (100S/DIV) www.richtek.com DS9269-01 March 2003 6 Preliminary RT9269 Power Up Waveform VCE = 1.25V VIN = 3.8V IOUT = 20mA Power On Waveform VCE = VIN = 3.8V IOUT = 20mA VCE VCE IIN IIN IOUT CH1: 2V/DIV Refer to Application Circuit Fig. 2 IOUT CH1: 2V/DIV Refer to Application Circuit Fig. 2 Time (10mS/DIV) Time (500S/DIV) Shutdown Waveform VCE = 1.25V VIN = 3.8V IOUT = 20mA VLX IIN IOUT VOUT Refer to Application Circuit Fig. 2 CH1: 2V/DIV LX vs. Ripple Waveform VLX VCE = VIN = 3.8V IOUT = 20mA IOUT Refer to Application Circuit Fig. 2 CH1: 2V/DIV Time (500S/DIV) Time (1S/DIV) Power On Waveform VCE = VIN = 3.2V IOUT = 40mA VIN IIN IIN VIN Power Up Waveform VCE = 1.2V VIN = 3.2V IOUT = 40mA CH1: 2V/DIV CH2: 200mA/DIV IOUT IOUT CH1: 2V/DIV CH2: 100mA/DIV VLX Refer to Application Circuit Fig. 1 VLX Refer to Application Circuit Fig. 1 Time (5mS/DIV) Time (250S/DIV) DS9269-01 March 2003 www.richtek.com 7 RT9269 Shutdown Waveform VIN Preliminary LX vs. Output Ripple Waveform VCE = 1.2V VIN = 3.2V IOUT = 40mA VIN IIN IIN VCE = VIN = 3.2V IOUT = 40mA CH1: 1V/DIV IOUT CH1: 2V/DIV CH2: 200mA/DIV VOUT Ripple Refer to Application Circuit Fig. 1 VLX Refer to Application Circuit Fig. 1 Time (250S/DIV) Time (1S/DIV) Brightness Control Brightness Control VIN LX 80% Duty External Signal VIN LX 80% Duty External Signal CE CE IOUT VIN = 3.0V IOUT = 20mA IOUT VIN = 2.5V IOUT = 20mA Time (1mS/DIV) Time (1mS/DIV) www.richtek.com DS9269-01 March 2003 8 Preliminary Package Information RT9269 H D L C B b A A1 e Symbol A A1 B b C D e H L Dimensions In Millimeters Min 0.889 -1.397 0.356 2.591 2.692 0.838 0.102 0.356 Max 1.295 0.152 1.803 0.559 2.997 3.099 1.041 0.254 0.610 Dimensions In Inches Min 0.035 -0.055 0.014 0.102 0.106 0.033 0.004 0.014 Max 0.051 0.006 0.071 0.022 0.118 0.122 0.041 0.010 0.024 SOT- 26 Surface Mount Package DS9269-01 March 2003 www.richtek.com 9 RT9269 Preliminary RICHTEK TECHNOLOGY CORP. Headquarter 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 RICHTEK TECHNOLOGY CORP. Taipei Office (Marketing) 8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com www.richtek.com DS9269-01 March 2003 10 |
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