rt9271 Richtek Technology Corporation, rt9271 Datasheet
rt9271
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rt9271 Summary of contents
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... The input and output capacitor can be as small as 1uF, saving space and cost versus alternative solutions. A low 0.25V feedback voltage minimizes power loss in the current setting resistor for better efficiency. The RT9271 is available in low profile SOT-26 package. Ordering Information RT9271 Package Type ...
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... RT9271 Typical AppIication Circuit V 2.4 to 3. Figure 2. RT9271 Drivers 2 Series WLEDs Application Circuit V 2 Figure 3. RT9271 Drivers 3 Series WLEDs Application Circuit www.richtek.com 2 Preliminary LX C1 10uH 1uF IN VCC LX OVP CE Dimming Control GND FB Figure 1. RT9271 Drivers 1 WLED Application Circuit LX C1 10uH 1uF IN VCC ...
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... V 2 Figure 4. RT9271 Drivers 4 Series WLEDs Application Circuit Note : Schottky diode (SS0520 are the WLED (HT-S91CW-DT) of HARVATEK the SH4018 series of ABC TAIWAN ELECTRONICS CORP. Recommended Circuits for Driving LED’ s Figure 1 to Figure 4 illustrates the recommended application circuits for driving white LED’ s. The series connected LED’ ...
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... RT9271 Absolute Maximum Ratings Supply Voltage, V -------------------------------------------------------------------------------------------------- 0. LX, OVP ----------------------------------------------------------------------------------------------------------------- 0.3V to 21V The Other Pins -------------------------------------------------------------------------------------------------------- 0. Maximum Junction Temperature ---------------------------------------------------------------------------------- 125 C Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------- 260°C Storage Temperature Range --------------------------------------------------------------------------------------- 65°C to 150°C ESD Susceptibility (Note 2) HBM ---------------------------------------------------------------------------------------------------------------------- 2kV MM ------------------------------------------------------------------------------------------------------------------------ 200V Recommended Operating Conditions Supply Voltage, V -------------------------------------------------------------------------------------------------- 2 ...
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... ENABLE Operation The RT9271 uses a constant frequency, current mode control scheme to provide excellent line and load regulation. Operation can be best understood by referring to the block diagram. At the start of each oscillator cycle, the SR latch is set, which turns on the power switch M1. A voltage proportional to the switch current is added to a stabilizing ramp and the resulting sum is fed into the positive terminal of the PWM comparator A2 ...
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... RT9271 Typical Operating Characteristics Efficiency vs. V (Driving 1 WLED 2 (V) IN Efficiency vs. V (Driving 3 WLEDs (V) IN Frequency vs. V 1.3 Driving 3 WLEDs 1.2 1.1 1 0.9 0.8 0 ...
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... LX 3 WLEDs 2. OUT (AC 100mA/Div OUT (AC 100mA/Div RT9271 Stability for Driving 1 WLED I IN Time (500 ns/Div) Stability for Driving 2 WLEDs I IN Time (500 ns/Div) Stability for Driving 2 WLEDs I IN Time (500 ns/Div) 100mA/Div 100mA/Div 100mA/Div www.richtek.com 7 ...
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... RT9271 Stability for Driving 3 WLEDs OUT (AC Time (500 ns/Div) Stability for Driving 3 WLEDs OUT (AC Time (500 ns/Div) Stability for Driving 4 WLEDs OUT (AC Time (500 ns/Div) www.richtek.com 8 Preliminary OUT (AC 100mA/Div ...
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... 730mA IN(max OUT 730mA IN(max) V OUT RT9271 Inrush Current for Driving 2 WLEDs Frequency = 200Hz I IN(max) Time (20 us/Div) Inrush Current for Driving 4 WLEDs Frequency = 200Hz I IN(max) Time (20 us/Div) Dimming Control for Driving 4 WLEDs Time (20 us/Div) = 730mA = 750mA V = 3.6V IN www ...
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... PWM signal. The average LED current increases proportionally with the duty cycle of the PWM signal duty cycle will turn off the RT9271 and corresponds to zero LED current. A 100% duty cycle corresponds to full current. The magnitude of the PWM signal should be higher than minimum CE voltage high ...
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... DS9271-02 October 2003 Preliminary 10uH SS0520 1uF VCC LX OVP EN GND FB RT9271 Figure 7. Recommended Soft-Start Circuit VCC LX OVP CE RT9271 S3 FB GND EVB Circuit C6 10nF C3 1uF R3 1KΩ 12Ω 10KΩ Bottom Layer - RT9271 www.richtek.com 11 ...
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... RT9271 Outline Dimension Symbol RICHTEK TECHNOLOGY CORP. Headquarter 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 www.richtek.com 12 Preliminary Dimensions In Millimeters Min Max 0.889 1.295 -- 0.152 1.397 1.803 0.356 0.559 2.591 2.997 2 ...