SC4505 Semtech Corporation, SC4505 Datasheet
SC4505
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SC4505 Summary of contents
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... IO2SET 6.98k 9 AGND RO2SET 1.54k Figure 1. SC4505 Application Circuit for Backlight and Flashlight LED Driver Revision: December 15, 2006 High Efficiency Boost Converter for Backlight/Flash LED Driver Features Two independent current sources for dual LED strands with optimal current/light matching. Backlight up to 75mA, Flash up to 125mA Wide input range from 2 ...
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... SC4505 ° ° C ° C ° ...
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... SC4505 µ µ ° C ° ...
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... E Notes: (1) Only available in tape and reel packaging. A reel contains 3000 devices. (2) Lead free product. This product is fully WEEE and RoHS compliant. VO OVP OSC Comparator IO1 ADJ1 EN_FL FL_TRB PGND 4 SC4505 ...
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... Table 2 SC4505 ...
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... LED currents use two separate converter ICs, greatly increasing component count and BOM cost. The SC4505 solves these issues by controlling the boost converter set point based on instantaneous requirements of the two current regulators. Therefore, only a single ...
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... POWER MANAGEMENT Applications Information Boost Converter Setup The SC4505 is a fixed-frequency, current mode step-up DC-DC converter that is ideal for driving LEDs in the applications in which both backlighting and flashlighting are needed. Unlike the ballasting resistor scheme, multiple strands can be independently controlled, or shut off entirely without leaking current from a charged output capacitor www ...
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... Table 4. Recommended Inductors Output Capacitor Selection The next task in SC4505 design is targeting the proper amount of ripple voltage due to the constant-current LED loads. The two error amplifiers that control the PWM converter sense the delta between requested current and actual current in each output current regulator. On ...
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... Manufacturers www.DataSheet4U.com Output Rectifying Diode Selection Schottky diodes are the ideal choice for SC4505 due to their low forward voltage drop and fast switching speed. Table 6 shows several different Schottky diodes that work well with the SC4505. Make sure that the diode has a voltage rating greater that the possible maximum ouput voltage ...
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... For an example, suppose the current flowing through www.DataSheet4U.com the I channel is programmed at 20mA PWM signal with the duty ratio of 20% is applied to the EN_BL pin of the SC4505. Then the average current flowing through the I channel 20% O1AVG A startup delay time between the enable signal goes high and the internal current regulator actually turns on is about 1 ...
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... OVP triggering threshold. 2006 Semtech Corp. VOUT C OUT are the internal resistor 2 and will slow down the 28V //500K 100K 1 83.3K should also be considered 4 11 SC4505 www.semtech.com ...
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... VIN 2006 Semtech Corp. As shown in Figure 6a, C1 serves as decoupling capacitor for the SC4505. It should be placed close to the VIN and PGND of SC4505 to achieve the best performance the input power filtering capacitor for the boost converter power train the boost converter input inductor ...
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... It should be connected to analog ground. R3 and R4 are the output current programming resistors for I respectively. R3 and R4 should return to analog ground. Since there is pad at the bottom of the SC4505 for heat dissipation, as shown in Figure 6a, a copper area right underneath the pad is used for better heat spreading. ...
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... Input Voltage (V) 14 10BQ015 D5 LED: SML-LX0603UWD 2.2uF 1.47k 12n 12n open (Optional) (Optional) C8 12n 0 0 =20mA and I =100mA O1 O2 =20m 4.5 5 SC4505 D6 LED LED D7 LED LED D8 LED LED D9 LED LED www.semtech.com ...
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... D .114 .118 .122 2.90 3.00 3.10 D1 .061 .067 .071 1.55 1.70 1.80 E .114 .118 .122 2.90 3.00 3.10 E1 .061 .067 .071 1.55 1.70 1.80 e .020 BSC 0.50 BSC L .012 .016 .020 0.30 0.40 0. aaa .003 0.08 bbb .004 0.10 DIMENSIONS INCHES MILLIMETERS (.114) (2.90) .083 2.10 .067 1.70 .067 1.70 .020 0.50 .006 0.15 .012 0.30 .031 0.80 .146 3.70 SC4505 www.semtech.com ...