BD9479FV ROHM [Rohm], BD9479FV Datasheet
BD9479FV
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BD9479FV Summary of contents
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... White LED Driver for large LCD Panels (DCDC Converter type) BD9479FV ●General Description BD9479FV is a high efficiency driver for white LEDs and designed for large LCDs. This IC is built-in a boost DCDC converters that employ an array of LEDs as the light source. BD9479FV has some protect function ...
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... OVP, STB, PWM1-8,VREF,UVLO REG50, N, CS, CP, LSP, CL1-8, FB, SS Ta(opr) Tstg Tjmax Symbol VCC VREF VLSP FCT F_PWM ● ● ● ● Marking diagram and physical dimension BD9479FV 1PIN MARK Figure 4. Physical Dimension TSZ02201-0F1F0C100020-1-2 2/26 Datasheet Ratings Unit ...
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... BD9479FV ●Electrical Characteristics (Unless otherwise noted Parameter [Whole Device] Operation current Standby current [UVLO Block] Operation Voltage （VCC） Hysteresis Voltage （VCC） Operation Voltage （UVLO） Hysteresis Voltage（UVLO） [DC/DC Block] Error amp Base Voltage Oscillation frequency N pin MAX DUTY output ...
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... BD9479FV ●Electrical Characteristics (Unless otherwise noted Parameter [LED protection Block] LED OPEN Detect Voltage LED SHORT Detect Voltage CL pin Detect Voltage LSP pin pull high resistor LSP pin pull down resistor [REG50 Block] REG50 output Voltage REG50 maximum output current ...
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... BD9479FV ●Pin Descriptions Pin No Pin Name In/Out 1 REG50 Out 2 N Out 3 PGND OVP Out 7 LSP In 8 STB In 9 BS1 In 10 BS2 In 11 BS3 In 12 BS4 In 13 BS5 In 14 BS6 In 15 BS7 In 16 BS8 In 17 PWM1 In 18 PWM2 In 19 ...
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... BD9479FV ● ● ● ● Pin ESD Type REG50 / N / PGND / (1-8) (1-8) FB www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 REG50 N 100k PGND CS LSP PWM (1-8) SS Figure 5-1. Pin ESD Type 6/26 Datasheet OVP STB VREF RT TSZ02201-0F1F0C100020-1-2 9.Aug.2012 Rev.001 ...
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... BD9479FV UVLO ●Block Diagram www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 FAIL Figure 5-2. Pin ESD Type Figure 6. Block Diagram 7/26 Datasheet TSZ02201-0F1F0C100020-1-2 9.Aug.2012 Rev.001 ...
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... BD9479FV ●Typical Performance Curve Figure 7. Operating Current (ICC) [mA] vs. VCC[ VCC [V] Figure 9. CL1 Voltage (VRCL1) [V] vs. VREF [V] 2 1.6 1.2 0.8 0.4 0 0.6 1.1 1.6 VREF [V] Figure 11. CL1 Voltage (VRCL1) [V] vs. Temp [℃] 400 380 360 340 320 300 280 260 240 220 ...
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... The CS pin also incorporates the overcurrent protection (OCP) function. If the CS pin voltage reaches 0.4V (Typ.) or more, switching operation will be forcedly stopped. In order to prevent the malfunction while OCP occurred in BD9479FV,it equipped with mask function.It mask OCP signal within 200ns interval after N driver is outputted. ...
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... STB pin become high, it wait for in any one PWMx signal from low to high.In start-up duration, SS will not charge because all PWMx pin are in low state. The BD9479FV has a built-in soft start startup circuit independent of PWM light modulation, and thereby raises FB voltage as SS pin voltage rises independent of the duty cycle range of PWM light modulation.Please pay attention to overshoot problem will occur while low duty is inputted start-up duration ...
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... Later, VREF＝0.9V will be set as basic.For example if you create 0.9V from REG50 possible to use resistive divider by setting 82kohm and 18kohm. In BD9479FV, the LED current detection is performed by CLx pin.CLx pin is controlled so that the voltage of 1/3V(typ.) of VREF voltage.If VREF=0.9V, CLx=0.3V to control external PNP Tr.Therefore,if 「R GND, and VREF pin voltage is set as 「 ...
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... Maximum DCDC output Voltage In BD9479FV, the voltage of BSx pin is depending on VREF pin voltage.The maximum voltage of VREF pin（VREF＝ 3.0V）, the voltage of BSx pin will become 2.0V（2/3 of VREF voltage ）. The maximum voltage of DCDC output will have be vary with 1.6V while Analog dimming is performed (2/3 of 3.0V - 0.6V). ● ...
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... BD9479FV ● ● ● ● Start-up and soft start (SS) capacitance setting The following describes the start-up sequence of this IC. ○ ○ ○ ○ Description of start-up sequence ①Set STB from Low to High ②System will be activated while PWM=H.SS start to charge. At this time, a circuit in which SS pin voltage for slow start becomes equal to FB pin voltage operates to equalize the FB pin and SS pin voltages regardless of whether the PWM pin is set to Low or High l eve. ③ ...
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... BD9479FV ● ● ● ● UVLO setting procedure It is UVLO function for the DC/DC converter power supply.If its voltage reaches 3.0V (Typ.) or higher, the IC will start step-up operation reaches 2.79V (Typ.) or less, the IC will stop the step-up operation.The UVLO pin is the high impedance type and involves no pull-down resistor, resulting in unstable operation in the open-circuited state ...
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... There are two type of BD9479FV.The one is OVP detection, another is OVP feedback. Basically, the CP pin start to charge when OVP pin voltage higher than 2.25V.when OVP pin voltage is between 2.25V with 2.5V, the operation of DCDC is continued and CP start to charge only.When OVP pin voltage reaches 2.5V, until then the feedback voltage control will be switch from BSｘ ...
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... BD9479FV ● ● ● ● LED short voltage setting(BSx pin, LSP pin) The detection voltage of LED short when BSx pin higher than 9V while LSP pin is in OPEN state possible to change the LED short detection voltage, please input (0.3V～3.0V) to LSP pin. ...
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... BD9479FV ● ● ● ● Timer latch time (CP Pin) The CP pin will source 2.0uA current when any abnormal problem is detected.Even is an error is detected, IC does not stop as long as CP pin is not to 2.5V.CP pin which sets the time from detection of abnormality until shutdown (Timer latch). ...
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... BD9479FV ● ● ● ● OCP setting / DCDC component current tolerance selection guide The OCP detection function that is one of the functions of the CS pin will stop the DC/DC converter operating ifthe CS pin voltage becomes larger than 0.4V.Consequently needed to calculate a peak current flowing through the coil L and then review the resistance of RCS ...
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... BD9479FV DC/DC application components including FETs, inductors, and diodes should be selected so that the Equation shown above will be met. In addition recommended to use continuous mode in DCDC application.And the lower limit value of coil ripples current Imin meet the following equation: I min A failure to meet this condition is referred to as discontinuous mode and this failure may result in an inadequate rise in output voltage. 【 ...
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... BD9479FV ● ● ● ● Selection of inductor L Δ OUT OUT ※ current in excess of the rated current of the inductor applies to the coil, the inductor will cause magnetic saturation, resulting in efficiency degradation. Select an inductor with an adequate margin so that peak current will not exceed the rated current of the inductor. ...
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... BD9479FV ● ● ● ● Selection of switching MOSFET transistors There will be no problem for switching MOSFET transistors having absolute maximum rating higher than rated current of the inductor L and VF higher than “C switching, select transistors with small gate capacity (injected charge amount). ...
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... BD9479FV Phase Compensation Setting Procedure ● ● ● ● DC/DC converter application for current mode control includes one each of pole f of output capacitor and output resistor (i.e., LED current) and zero (phase lead) f ESR. Furthermore, the step-up DC/DC converter includes RHP zero “f phase delay ( 90 ) characteristics like the pole, the crossover frequency f ...
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... BD9479FV ● ● ● ● Timing Chart www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 TSZ02201-0F1F0C100020-1-2 23/26 Datasheet 9.Aug.2012 Rev.001 ...
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... BD9479FV ● ● ● ● List of Protect Function (typ condition) Protection Detection Name Pin BSx LED OPEN CLx LED SHORT BSx UVLO UVLO REG50 VCC OVP OVP Feedback OVP OVP SCP OVP OCP CS To release the latch function, STB should be set to “L” once, and then to “H”. ...
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... BD9479FV ● ● ● ● Operational Notes 1) We pay utmost attention to the quality control of this product. However exceeds the absolute maximum ratings including applied voltage and operating temperature range, it may lead to its deterioration or breakdown. Further, this makes it impossible to assume a breakdown state such as short or open circuit mode. If any special mode to exceed the absolute maximum ratings is assumed, consider adding physical safety measures such as fuses ...
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... BD9479FV ● ● ● ● Ordering Information Part Number ●Physical Dimension Tape and Reel Information SSOP-B40 13.6 0.2 (MAX 13.95 include BURR 0.15 0.1 S 0.65 0.22 0.1 0.08 M (Unit : mm) www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 Package Packaging and forming specification ...
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Precaution 1) Before you use our Products, you are requested to carefully read this document and fully understand its contents. ROHM shall not be in any way responsible or liable for failure, malfunction or accident arising from the use ...
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Mounting / Circuit board design 1) When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product performance and reliability principle, the reflow soldering method must be used; ...
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Precaution 1) The information contained in this document is provided on an “as is” basis and ROHM does not warrant that all information contained in this document is accurate and/or error-free. ROHM shall not be in any way responsible ...