BD9479FV ROHM [Rohm], BD9479FV Datasheet - Page 14

• 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
● ● ● ● UVLO setting procedure
resistance setting is decided by the following equation:
○ ○ ○ ○ UVLO detection setting equation
following equation:
○ ○ ○ ○ UVLO release voltage setting equation
UVLO release voltage will be given by the following equation:
【 【 【 【 Setting example】 】 】 】
Furthermore, VIN
*For the selection of DC/DC components, please also consider the inaccuracy of each componentts.
step-up operation. If it 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. Avoid this
problem, please make sure to input voltage by using resistor divider or otherwise.
If the VIN pin voltage to be detected is set by resistor divider R1 and R2 as described below, resistance setting will be
made by the following equation:
Assuming that the VIN input voltage is 24V, UVLO detection voltage is 17.36V, and R2 resistance is 13kΩ, R1
Assuming that a voltage VIN decreasing, UVLO is “VIN
When R1 and R2 setting is determined by the equation shown above,
It is UVLO function for the DC/DC converter power supply.If its voltage reaches 3.0V (Typ.) or higher, the IC will start
VIN
R
1
CAN
R
[ 2
k
3
VIN
CAN
R
[ 0 .
1
]
can be calculated as below equation when R1(68kΩ), R2(13kΩ) are decided above
V
CAN
(
]
VIN
R
[ 2
(
k
R
DET
3
[ 1
0 .
. 2
]
k
[
V
V
79
R
(
]
]
[ 2
VIN
[
V
(
k
R
. 2
R
]
[ 1
DET
79
[ 2
]
k
k
. 2
[
R
[
V
V
79
]
[ 2
])
])
]
k
[
V
R
14/26
. 2
[ 2
]
13
]
3
79
DET”
[ 0 .
k
[
k
[
V
, R1 and R2 setting will be made by
V
])
]
])
]
13
[
(
V
17
[
[
k
]
k
.
36
13
]
]
[
[
. 2
V
k
79
]
68
]
[
[
V
. 2
k
]
79
TSZ02201-0F1F0C100020-1-2
]
[
[
V
V
]
])
18
9.Aug.2012 Rev.001
68
.
69
[
k
[
V
]
Datasheet
]
the