RT9269 Tiny Package, High Efficiency, Constant Current LED Driver General Description Features 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. z The 0.25V low reference voltage minimized the power loss across the current-setting resistor. z z z z z z 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. Ordering Information RT9269 z 0.25V Low Reference Voltage 17μ μA 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 z z z z z LED Module Hand Held Panel Compact Back Light Module Small Battery Charger Constant Current Source Pin Configurations (TOP VIEW) FB VDD 6 Package Type E : SOT-23-6 Lead Plating System P : Pb Free G : Green (Halogen Free and Pb Free) LX 5 4 2 3 EN EXT GND SOT-23-6 Note : Richtek 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. Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. DS9269-12 April 2011 www.richtek.com 1 RT9269 Typical Application Circuit D1 D2 VIN C1 1uF C3 1uF C2 1uF VDD EXT RT9269 To VDD or EN 0.25V FB GND R1 15 Duty Control Brightness R2 15 Figure 1. RT9269 drives single or parallel LED's in charge pump configuration D1 D2 VIN C1 1uF C3 1uF C2 1uF VDD EXT RT9269 To VDD or EN 0.25V FB GND R1 15 Duty Control Brightness Figure 2. RT9269 drives 2 series connected LED's in charge pump configuration VIN C2 10uF R1 1K L1 10uH to 100uH Q1 C1 1uF C3 10uF VDD LX RT9269 To VDD or EN FB GND Duty Control Brightness 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 DS9269-12 April 2011 RT9269 Functional Pin Description Pin No. Pin Name Pin Function 1 EN Chip Enable (Active High) 2 EXT Output Pin for Configuring Charge Pump or Driving External NMOS 3 GND Ground 4 LX Pin for Switching 5 VDD Input Positive Power Pin of RT9269 6 FB Feedback Input pin Internal Reference Voltage for the Error Amplifier is 0.25V. Function Block Diagram RT9269 VDD EXT LX - FB + 1.25V Loop Control Circuit Q1 N MOS R1 VDD R2 Shut Down EN DS9269-12 April 2011 Q2 N MOS Over Temp. Detector GND www.richtek.com 3 RT9269 Absolute Maximum Ratings z z z z z z z z z 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 Symbol Test Conditions Min Typ Max Unit Start-UP Voltage VST IL = 1mA -- 0.98 1.05 V Operating VDD Range VDD VDD pin voltage 2 -- 6.5 V No Load Current I (VIN) INO LOAD VIN = 3.3V, V OUT = 5V -- 30 -- μA Switch-off Current I (VDD) ISWITCH VIN = 6V -- 17 -- μA Shutdown Current I (VIN ) IOFF EN Pin = 0V, VIN = 6V -- 0.1 1 μA Feedback Reference Voltage VREF Close Loop, VDD = 5V Switching Rate FS VDD = 5V -- 500 -- kHz Maximum Duty DMAX VDD = 5V -- 75 -- % VDD = 5V -- 0.4 -- Ω VDD = 5V -- 500 -- mA EXT ON Resistance to V DD VDD = 5V -- 5 -- Ω EXT ON Resistance to GND VDD = 5V -- 5 -- Ω EN Pin Trip Level VDD = 5V 0.4 0.8 1.2 V LX ON Resistance Current Limit Setting ILIMIT 0.25 V Temperature Stability for VREF TS -- 50 -- ppm/°C Thermal Shutdown TSD -- 165 -- °C Thermal Shutdown Hysterises ΔTSD -- 10 -- °C www.richtek.com 4 DS9269-12 April 2011 RT9269 Typical Operating Characteristics Efficiency vs. VIN Efficiency vs. Input Voltage 89 85 6LEDs, L = 33uH 4LEDs, L = 47uH 84 83 Efficiency(%) Efficiency (%) 87 85 IOUT = 20mA 83 IOUT = 20mA 82 81 IOUT = 15mA 81 IOUT = 15mA 80 79 79 2.5 3 3.5 4 4.5 5 5.5 3 6 3.5 4 Input Voltage (V) 4.5 5 5.5 6 VIN(V) Efficiency vs. Input Voltage Frequency vs. VDD 600 100 500 90 Efficiency (%) Frequency(kHz) A IOUT = 20mA @VIN > 3.8V 400 300 200 IOUT = 15mA 80 @VIN > 70 60 100 Refer tp Application Circuit Figure 2 FB = GND, TA=25°C 50 0 0 1 2 3 4 5 3 6 3.5 4 VDD (V) VFB vs. Ambient Temperature 256 4.5 5 5.5 6 Input Voltage (V) Efficiency vs. Output Current 100 90 254 Efficiency (%) 80 VFB (mV) 252 250 248 VIN = 2.7V 70 VIN = 4.2V 60 VIN = 3.6V 50 40 246 30 20 244 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 Ambient Temperature (°C) DS9269-12 April 2011 0.1 1 10 100 Output Current (mA) www.richtek.com 5 RT9269 Power ON Waveform Power ON Waveform VIN = 3.0V for 4LEDs VIN = 2.5V for 4LEDs VIN VIN LX LX 200mA/Div 200mA/Div I IN I IN 20mA/Div IOUT Refer tp Application Circuit Figure 3 20mA/Div IOUT Refer tp Application Circuit Figure 3 Time (2.5ms/Div) Time (2.5ms/Div) LX vs. Output Ripple LX vs. Output Ripple VIN = 3.0V for 4LEDs VIN = 2.5V for 4LEDs LX LX VOUT VOUT IOUT 20mA/Div 20mA/Div 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 LX VIN = 2.5V,IOUT = 20mA VIN = 3.0V,IOUT = 20mA EN EN 20mA/Div 20mA/Div IOUT IOUT Refer tp Application Circuit Figure 3 Time (250us/Div) www.richtek.com 6 Refer tp Application Circuit Figure 3 Time (100us/Div) DS9269-12 April 2011 RT9269 Power On Waveform Power Up Waveform VEN = VIN = 3.8V IOUT = 20mA VEN VEN I IN I IN VEN = 1.25V VIN = 3.8V IOUT = 20mA IOUT IOUT Refer tp Application Circuit Figure 2 Refer tp Application Circuit Figure 2 Time (10ms/Div) Time (500us/Div) EN Pin Shutdown Response LX vs. Output Ripple VEN = VIN = 3.8V, IOUT = 20mA VEN = 1.25V VIN = 3.8V IOUT = 20mA VLX VLX I IN IOUT VOUT IOUT Refer tp Application Circuit Figure 2 Refer tp Application Circuit Figure 2 Time (500us/Div) Time (1us/Div) Power On Waveform Power Up Waveform VEN = VIN = 3.2V IOUT = 40mA VIN VIN VEN = 1.2V, VIN = 3.2V IOUT = 40mA I IN I IN IOUT IOUT VLX VLX Refer tp Application Circuit Figure 1 Time (5ms/Div) DS9269-12 April 2011 Refer tp Application Circuit Figure 1 Time (250us/Div) www.richtek.com 7 RT9269 LX vs. Output Ripple EN Pin Shutdown Response VEN = VIN = 3.2V, IOUT = 40mA VIN VEN = 1.2V VIN = 3.2V IOUT = 40mA I IN VIN IOUT I IN VLX VOUT Refer tp Application Circuit Figure 1 Refer tp Application Circuit Figure 1 Time (250us/Div) Time (1us/Div) Brightness Control Brightness Control VIN VIN LX LX EN IOUT 80% Duty External Signal VIN = 3.0V IOUT = 20mA Time (1ms/Div) www.richtek.com 8 EN IOUT 80% Duty External Signal VIN = 2.5V IOUT = 20mA Time (1ms/Div) DS9269-12 April 2011 RT9269 Outline Dimension H D L C B b A A1 e Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 0.889 1.295 0.031 0.051 A1 0.000 0.152 0.000 0.006 B 1.397 1.803 0.055 0.071 b 0.250 0.560 0.010 0.022 C 2.591 2.997 0.102 0.118 D 2.692 3.099 0.106 0.122 e 0.838 1.041 0.033 0.041 H 0.080 0.254 0.003 0.010 L 0.300 0.610 0.012 0.024 SOT-23-6 Surface Mount Package Richtek Technology Corporation Richtek Technology Corporation Headquarter Taipei Office (Marketing) 5F, No. 20, Taiyuen Street, Chupei City 5F, No. 95, Minchiuan Road, Hsintien City Hsinchu, Taiwan, R.O.C. Taipei County, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 Tel: (8862)86672399 Fax: (8862)86672377 Email: [email protected] Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek. DS9269-12 April 2011 www.richtek.com 9