RT9269

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 17μA low quiescent current together with high efficiency maintains long battery lifetime. The output current is set with 1 external resistor. And the chip enable (EN) pin can be used for tuning the LED brightness by controlling the ON/OFF duty with external clock. RT9269 is provided in SOT-23-6 package. Features 0.25V Low Reference Voltage 17μA Quiescent (Switch-off) Supply Current Zero Shutdown Mode Supply Current 85% Efficiency 500kHz Fixed Switching Rate Tuning LED brightness with EN Pin ON/OFF Duty Small SOT-23-6 Package RoHS Compliant and 100% Lead (Pb)-Free Applications LED Module Hand Held Panel Compact Back Light Module Small Battery Charger Constant Current Source Pin Configurations (TOP VIEW) FB VDD 5 2 LX 4 3 Ordering Information RT9269 Package Type E : SOT-23-6 Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard) 6 1 EN EXT GND SOT-23-6 Note : There is no pin1 indicator on top mark for SOT-23-6 type, and pin 1 will be lower left pin when reading top mark from left to right. Note : RichTek Pb-free and Green products are : RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. 100%matte tin (Sn) plating. 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. DS9269-10 March 2007 www.richtek.com 1 RT9269 Typical Application Circuit D1 VIN C1 1uF VDD EXT RT9269 To VDD or Duty Control Brightness EN GND FB 0.25V C2 1uF D2 C3 1uF R1 15 R2 15 Figure 1. RT9269 drives single or parallel LED's in charge pump configuration D1 VIN C1 1uF VDD EXT RT9269 To VDD or Duty Control Brightness EN GND FB 0.25V C2 1uF D2 C3 1uF R1 15 Figure 2. RT9269 drives 2 series connected LED's in charge pump configuration VIN R1 1K C2 10uF L1 10uH to 100uH Q1 C1 1uF VDD LX RT9269 C3 10uF To VDD or Duty Control Brightness EN GND FB 0.25V R2 15 Figure 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 2 DS9269-10 March 2007 RT9269 Functional Pin Description Pin No. Pin Name 1 2 3 4 5 6 EN EXT GND LX VDD FB Pin Function Chip Enable (Active High) 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. Function Block Diagram VDD RT9269 EXT LX FB 1.25V VDD R2 Shut Down EN Q2 N MOS Over Temp. Detector + Loop Control Circuit Q1 N MOS R1 GND DS9269-10 March 2007 www.richtek.com 3 RT9269 Absolute Maximum Ratings Supply Voltage ----------------------------------------------------------------------------------------------------- −0.3V to 7V LX Pin Switch Voltage -------------------------------------------------------------------------------------------- −0.3V to (VDD +0.8V) Other I/O Pin Voltages ------------------------------------------------------------------------------------------- −0.3V to (VDD +0.3V) LX Pin Switch Current -------------------------------------------------------------------------------------------- 2.5A EXT Pin Driver Current -------------------------------------------------------------------------------------------- 200mA Power Dissipation, PD @ TA = 25°C SOT-23-6 ------------------------------------------------------------------------------------------------------------ 0.25W Package Thermal Resistance SOT-23-6, θJA ------------------------------------------------------------------------------------------------------- 250°C/W Operating Junction Temperature ------------------------------------------------------------------------------- 125°C Storage Temperature Range ------------------------------------------------------------------------------------ −65°C to +150°C Electrical Characteristics (VIN =3.3V, VDD set to 5V, Load Current = 0, TA = 25°C, 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 EN Pin Trip Level Temperature Stability for VREF Thermal Shutdown Thermal Shutdown Hysterises Symbol VST VDD INO LOAD ISWITCH IOFF VREF FS DMAX Test Conditions IL = 1mA VDD pin voltage VIN = 3.3V, VOUT = 5V VIN = 6V EN Pin = 0V, VIN = 6V Close Loop, VDD = 5V VDD = 5V VDD = 5V VDD = 5V Min -2 ---- Typ 0.98 -30 17 0.1 0.25 Max 1.05 6.5 --1 Units V V μA μA μA V ------0.4 ---- 500 75 0.4 500 5 5 0.8 50 165 10 ------1.2 ---- kHz % Ω mA Ω Ω V ppm/°C °C °C ILIMIT VDD = 5V VDD = 5V VDD = 5V VDD = 5V TS TSD ΔTSD www.richtek.com 4 DS9269-10 March 2007 RT9269 Typical Operating Characteristics Efficiency vs. Input Voltage 89 85 Efficiency vs. VIN 6LEDs, L = 33uH 4LEDs, L = 47uH 87 84 Efficiency (%) 85 Efficiency(%) 83 IOUT = 20mA 83 IOUT = 20mA 82 81 80 79 81 IOUT = 15mA 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) Frequency vs. VDD 600 500 100 Efficiency vs. Input Voltage IOUT = 20mA @VIN > 3.8V 90 Frequency(kHz) A 400 300 200 100 Efficiency (%) 80 IOUT = 15mA @VIN > 70 60 FB = GND, TA=25°C 0 0 1 2 3 4 5 6 50 3 Refer tp Application Circuit Figure 2 3.5 4 4.5 5 5.5 6 VDD (V) Input Voltage (V) VFB vs. Ambient Temperature 256 254 252 Efficiency vs. Output Current 100 90 80 Efficiency (%) VFB (mV) 70 60 VIN = 2.7V VIN = 4.2V VIN = 3.6V 250 248 246 244 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 50 40 30 20 0.1 1 10 100 Ambient Temperature (°C) DS9269-10 March 2007 Output Current (mA) www.richtek.com 5 RT9269 Power ON Waveform VIN = 3.0V for 4LEDs Power ON Waveform VIN = 2.5V for 4LEDs VIN VIN LX 200mA/Div LX 200mA/Div I IN IOUT 20mA/Div Refer tp Application Circuit Figure 3 I IN 20mA/Div IOUT Refer tp Application Circuit Figure 3 Time (2.5ms/Div) Time (2.5ms/Div) LX vs. Output Ripple VIN = 3.0V for 4LEDs LX vs. Output Ripple VIN = 2.5V for 4LEDs LX LX VOUT 20mA/Div VOUT 20mA/Div IOUT IOUT Refer tp Application Circuit Figure 3 Refer tp Application Circuit Figure 3 Time (500ns/Div) ((500ns/Div) Time (1us/Div) Power UP Waveform Power UP Waveform VIN VIN LX VIN = 3.0V,IOUT = 20mA LX VIN = 2.5V,IOUT = 20mA EN IOUT 20mA/Div Refer tp Application Circuit Figure 3 EN IOUT 20mA/Div Refer tp Application Circuit Figure 3 Time (250us/Div) Time (100us/Div) www.richtek.com 6 DS9269-10 March 2007 RT9269 Power On Waveform VEN = VIN = 3.8V IOUT = 20mA Power Up Waveform VEN = 1.25V VIN = 3.8V IOUT = 20mA VEN VEN I IN I IN IOUT Refer tp Application Circuit Figure 2 IOUT Refer tp Application Circuit Figure 2 Time (10ms/Div) Time (500us/Div) EN Pin Shutdown Response VEN = 1.25V VIN = 3.8V IOUT = 20mA LX vs. Output Ripple VEN = VIN = 3.8V, IOUT = 20mA VLX I IN VLX IOUT VOUT IOUT Refer tp Application Circuit Figure 2 Refer tp Application Circuit Figure 2 Time (500us/Div) Time (1us/Div) Power On Waveform VEN = VIN = 3.2V IOUT = 40mA Power Up Waveform VIN I IN VEN = 1.2V, VIN = 3.2V IOUT = 40mA VIN I IN IOUT IOUT VLX Refer tp Application Circuit Figure 1 VLX Refer tp Application Circuit Figure 1 Time (5ms/Div) Time (250us/Div) DS9269-10 March 2007 www.richtek.com 7 RT9269 EN Pin Shutdown Response VIN VEN = 1.2V VIN = 3.2V IOUT = 40mA LX vs. Output Ripple VEN = VIN = 3.2V, IOUT = 40mA I IN VIN IOUT VLX Refer tp Application Circuit Figure 1 I IN VOUT Refer tp Application Circuit Figure 1 Time (250us/Div) Time (1us/Div) Brightness Control Brightness Control VIN LX 80% Duty External Signal VIN LX 80% Duty External Signal EN EN IOUT VIN = 3.0V IOUT = 20mA IOUT VIN = 2.5V IOUT = 20mA Time (1ms/Div) Time (1ms/Div) www.richtek.com 8 DS9269-10 March 2007 RT9269 Outline Dimension 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 0.000 1.397 0.250 2.591 2.692 0.838 0.080 0.300 Max 1.295 0.152 1.803 0.560 2.997 3.099 1.041 0.254 0.610 Dimensions In Inches Min 0.031 0.000 0.055 0.010 0.102 0.106 0.033 0.003 0.012 Max 0.051 0.006 0.071 0.022 0.118 0.122 0.041 0.010 0.024 SOT-23-6 Surface Mount Package Richtek Technology Corporation Headquarter 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 Richtek Technology Corporation Taipei Office (Marketing) 8F, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com DS9269-10 March 2007 www.richtek.com 9