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PDF BD9470AFM Data sheet ( Hoja de datos )
| Número de pieza | BD9470AFM | |
| Descripción | White LED driver | |
| Fabricantes | ROHM Semiconductor | |
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Datasheet
LED driver series for LCD back light
White LED driver for medium sized
and large sized LCD back light
BD9470AEFV・BD9470AFM
●General Description
BD9470AEFV and BD9470AFM are high efficiency
driver for white LED. They are designed for large sized
LCD. BD9470AEFV and BD9470AFM are built-in
DCDC converter that supply appropriate voltage for
light source.
BD9470AEFV and BD9470AFM are also built-in
protection function for abnormal state such as OVP:
over voltage protection, OCP: over current limit
protection of DCDC, SCP: short circuit protection, open
detection of LED string.
Thus they are used for conditions of large output
voltage and load conditions.
●Features
6ch LED constant current driver
LED maximum output current 250mA
Individual PWM dimming modulation allowed for
LEDs
±2% LED current accuracy (when each LED is set
to 130mA)
Built-in LED feedback voltage automatic adjustment
circuit according to LED current
Built-in start-up circuit independent of PWM light
modulation
built-in VOUT ・ FB voltage maintenance function
when PWM=Low（0%）
Built-in LED current stabilization circuit while
scanning operation is performed
Built-in VOUT discharge circuit while shutdown
Built-in LED protection (OPEN / SHORT protection)
Individual detection and individual LED OFF for
both open and short circuit
Adjustable LED short-circuit protection threshold
PWM-independent LED protection
VOUT over voltage protection (OVP) and reduced
voltage protection (SCP) circuit
Built-in failure indication function
Built-in ISET pin short-circuit protection circuit
●Typical Application Circuit
VIN
ISET
SS
PWM1
FB
PWM2
RT
PWM3
DCDC_GND
PWM4
N
PWM5
CS
PWM
PWM6
REG58
●Key Specifications
VCC supply Voltage range:
9.0V～35.0V
LED minimum output current:
40mA
LED maximum output current:
250mA
DCDC oscillation frequency: 150KHz(RT=100Kohm)
Operation circuit current:
6mA(typ.)
Operating temperature range:
-40℃～85℃
●Applications
■ LED driver for TV, monitor and LCD back light
●Package
HSOP-M28
HTSSOP-B28
W (Typ.) x D(Typ.) x H(Max.)
18.50mm x 9.90mm x 2.41mm
9.70mm x 6.40mm x 1.00mm
Figure 1. HSOP-M28
Figure 2. HTSSOP-B28
GND VCC
STB
FAIL
FAIL STB
OVP
LSP
LED6
UVLO
LED5
LED1
LED4
LED2
LED_GND
LED3
Figure 3. Typical Application Circuit
○Product structure：Silicon monolithic integrated circuit
www.rohm.com
© 2013 ROHM Co., Ltd. All rights reserved.
TSZ22111・14・001
○This product is not designed protection against radioactive rays
1/35
TSZ02201-0F10C1002000-1-2
19.Oct.2013 Rev.003
1 page  
BD9470AFM・BD9470AEFV
●Electrical Characteristics (unless otherwise specified, Ta = 25°C, VCC=24V)
Parameter
Symbol
Specification
Min Typ
Max
【LED Driver Block】
LEDｘ pin current accuracy1
⊿ILED1
-2 -
2
LEDｘ pin current accuracy2
⊿ILED2
-2.5 -
2.5
LEDｘ pin leakage current
⊿ILED3
-3.5
3.5
unit
%
%
%
ISET pin voltage
ILLED
-0.8 -
0.8 uA
LEDｘ pin current accuracy1
【LED protection Block】
VISET
1.3 1.5
1.7
V
ISET short circuit protection range
LEDｘSHORT protection voltage
LSP pin resistive divider(Higher
R)
LSP pin resistive divider(Lower R)
LEDｘ OPEN detect voltage
【REG58 BLock】
ISET_DET
VLSP
RULSP
RDLSP
VOPEN
-0.3
8.5
1860
540
0.15
- VISET×90% V
9 9.5 V
3100
5580
kΩ
900 1620
kΩ
0.20 0.25
V
REG58 output voltage 1
REG58_1
5.742 5.8
5.858
V
REG58 output voltage 2
REG58 max output current
REG58_2
| IREG58 |
5.713
15
5.8
－
5.887
-
V
mA
REG58_UVLOdetect voltage
REG58_TH
2.1 2.4
2.7
V
REG58_UVLO Hysteresis
REG58_HYS
100 200
400
mV
REG58 Discharge current
【STB Block】
REG58_DIS
3.0 5.0
7.0
uA
STB pin HIGH voltage
STBH
2 - 35 V
STB pin LOW voltage
STBL
-0.3 -
0.8 V
STB pin Pull Down resistance
【PWM Block】
PWMｘ pin HIGH voltage
PWMｘ pin LOW voltage
PWMｘ pin Pull Down resistance
【FAIL Block（OPEN DRAIN）】
RSTB
PWM_H
PWM_L
RPWM
600 1000
1800
kΩ
1.5
-0.3
1200
-
-
2000
15
0.8
3600
V
V
kΩ
FAIL Pin Ron
RFAIL
250 500
1000
Ω
FAIL Pin Leakage current
ILFAIL
-2 0
2 μA
Condition
ILED=130mA
ILED=150mA
ILED=250mA
STB=H,
LEDx=40V
RISET=30kΩ
PWMx=L,
ISET=SWEEP DOWN
LEDx=SWEEPUP,
LSP=OPEN
LSP=0V
LSP=4V
LEDx=SWEEP DOWN
IO=0mA
IO=-15mA
STB=ON
REG58=SWEEP DOWN
STB=ON->OFF
REG58=SWEEP DOWN
STB=ON->OFF REG58=4V
STB=SWEEP UP
STB=SWEEP DOWN
VSTB=3.0V
PWMｘ=SWEEP UP
PWMｘ=SWEEP DOWN
PWMｘ=3.0V
VFAIL=1.0V
VFAIL=5V
www.rohm.com
© 2013 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
5/35
TSZ02201-0F10C1002000-1-2
19.Oct.2013 Rev.003
5 Page 
BD9470AFM・BD9470AEFV
○LED1-6 （HTSSOP-B28:18,19,20,22,23,24PIN / HSOP-M28：11,12,13,15,16,17PIN）
LED constant current output pins. Current value setting can be made by connecting a resistor to the ISET pin.
For the current value setting procedure, refer to the description of “ISET pin”.
If any of the LED pins is put in an abnormality state (short circuit mode, open circuit mode, ground short mode), the
relevant protection function will be activated.
・LED pin short circuit protection function ( LSP)
When any LED is in short state (more than LED=9.0V(typ)) the LED SHORT is detected.
After abnormal detection, the timer count starts. The LED that is abnormal detection after 216 count is stopped and other
LED driver operates normally.
・LED pin open circuit protection function (LOP)
If any of the LED pins becomes open-circuited (0.2V (Typ.) or less), LED_OPEN will be detected. When this error is
detected, the timer will start counting, When it completes counting the preset period of time, only LED driver that detected
the error will stop operation and other LED driver will conduct normal operation.
・LED GND_SHORT protection function
When any LED pin is GND shorted the LED pin becomes less than 0.20V and the pin is latched because of LED_OPEN
detection. After that, the LED pin is pull upped by inner supply but it continues less than 0.2V state in grand shorted. After
detecting timer of open state, if the grand shorted (open) state continues 27 counts all systems are latched.
To prevent the miss detection there is 4 count interval of mask before starting the timer count.
If PWM=H time is
PWM=H time < 4count・・・Not detect protection because it is in interval time
PWM=H time > 4count・・・Detect protection because it is out of interval time
Please verify enough to operate narrow PWM.
LEDx
9V
Interval of mask
Timer count
CLK
1 23 41 2
216
FAIL
Figure 14. Timing chart of timer count
○LED_GND （HTSSOP-B28:21PIN / HSOP-M28：14PIN）
The LED_GND pin is a power ground pin used for the LED driver block.
○UVLO （HTSSOP-B28:25PIN / HSOP-M28：18PIN）
This pin is used to for step-up DC/DC converter. When UVLO pin voltage reaches 3.0V (Typ.) or more, IC will initiate
step-up operation. If it reaches 2.7V (Typ.) or less, the IC will stop the step-up operation.
The UVLO pin is of the high impedance type and involves no pull-down resistor, resulting in unstable potential in the
open-circuited state. To avoid this problem, be sure to make input voltage setting with the use of a resistive divider or
otherwise.
For calculation examples, refer to information in ’3.1 application explanation/UVLO setting procedure’
○LSP （HTSSOP-B28:26PIN / HSOP-M28：19PIN）
The setting pin for detection voltage of LED short circuit protection. The LED short circuit detection voltage is set to 9V
(Typ.) with the LSP pin being in the open-circuited state. However, making a change to the LSP pin input voltage will allow
the threshold for LED short circuit protection to be changed.
The relation between the LSP pin voltage and the LED short circuit protection detection voltage is given by the following
equation.
VLSPSHORT
= VLEDSHORT
10
[V ]
Here LEDSHORT：LED detection voltage
VLSP：LSP setting voltage
LSP pin input voltage setting should be made in the range of 0.3V to 2.5V.
For setting example, refer to information in’3.1 application explanation/LSP setting procedure’
www.rohm.com
© 2013 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
11/35
TSZ02201-0F10C1002000-1-2
19.Oct.2013 Rev.003
11 Page | ||
| Páginas | Total 30 Páginas | |
| PDF Descargar | [ Datasheet BD9470AFM.PDF ] | |
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