BD9479FV ROHM [Rohm], BD9479FV Datasheet - Page 12

• Manufacturer Part Number: BD9479FV
• Description: White LED Driver for large LCD Panels (DCDC Converter type)
• Manufacturer: ROHM [Rohm]

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© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
BD9479FV
● ● ● ● Maximum DCDC output Voltage
● ● ● ● Soft Start Time setting (SS Pin)
3.0V）, the voltage of BSx pin will become 2.0V（2/3 of VREF voltage ）.
0.6V).
charge of 2.0uA to the external capacitor connected with SS pin, and the each protection and CP charge function will not
activated before SS pin reaches to 4.0V.
（soft start time set here is mask time of CP charge, please pay attention to it is different from the time to stabilize DCDC
output.The time to stabilize DCDC output is largely depending on step-up ratio and load condition.）
The soft start time「T
The start-up time of DCDC output is adjusted by condenser which connected to SS pin.its performs constant current
In BD9479FV, the voltage of BSx pin is depending on VREF pin voltage.The maximum voltage of VREF pin（VREF＝
The maximum voltage of DCDC output will have be vary with 1.6V while Analog dimming is performed (2/3 of 3.0V -
If DCDC frequency is set to be 200kHz, RRT as below:
C
SS
[
F
]
R
RT
SS
T
」, and SS pin external condenser「C
SS
f
15000
sw
[sec]
[
kHz
]
4
[ 0 .
2
200
0 .
V
15000
]
[
kHz
10
]
6
[
75
A
12/26
]
SS
[
」 can be calculated as below.
k
]
TSZ02201-0F1F0C100020-1-2
9.Aug.2012 Rev.001
Datasheet