|
ROHM Semiconductor |
Datasheet
Boost 1channel white LED driver
For large LCDs
BD9488F
●General Description
BD9488F 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. BD9488F has some protect function against
fault conditions, such as the over-voltage protection
(OVP), the over current limit protection of DCDC (OCP),
LED over current protection (LEDOCP), the open
detection of LED string. Therefore BD9488F is available
for the fail-safe design over a wide range output voltage.
●Features
Current mode DCDC converter
Vout discharge circuit as shutdown
LED protection circuit (OPEN protection, LED OCP
protection)
LED protect detection as small PWM dimming signal
Over-voltage protection (OVP) for the output voltage.
Adjustable soft start time constant
The wide range of analog dimming 0.2V-3.5V
The built-in transformation circuit from pulse to DC
2 PWM dimming signal
The UVLO detection for the input voltage of the power
stage
FAIL logic output
●Applications
TV, PC display and other LCD backlight system.
●Key Specifications
Input voltage range:
9.0V to 18.0V
DCDC oscillation frequency: 150kHz (RT=100kΩ)
Active current consumption:
1.2mA(Typ.)
Operating temperature range:
-40℃ to +85℃
●Package(s)
SOP18
W(Typ.) x D(Typ.) x H(Max.)
11.20mm x 7.80mm x 2.01mm
Pin pitch 1.27mm
Figure 1. SOP18
●Typical Application Circuit(s)
VCC
VIN
VCC
TC54
UVLO OVP
STB
RT
Css
SS
GATE
CS
FAILB
PWM1
DIMOUT
PWM2
ADIM_P
ADIM
GND
ISENSE
FB
Figure 2. Typical application circuit
○Product structure:Silicon monolithic integrated circuit
.www.rohm.com
© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111・14・001
○This product is not designed protection against radioactive rays
1/38
TSZ02201-0F1F0C100040-1-2
27.May 2014 Rev.003
BD9488F
●Absolute Maximum Ratings (Ta=25℃)
Parameter
Input voltage
STB pin voltage
OVP, UVLO, SS, RT,
ISENSE, FB, CS, TC54
pin voltage
PWM1, PWM2, FAILB,
ADIM, ADIM_P pin voltage
DIMOUT, GATE pin voltage
Symbol
Vccmax
STB
OVP, UVLO, SS, RT,
ISENSE, FB, CS, TC54
PWM1, PWM2, FAILB,
ADIM, ADIM_P
DIMOUT, GATE
Power Dissipation
Pd
Operating Temperature Range
Topr
Junction Temperature
Tjmax
Storage Temperature Range
Tstg
*1 Pd derated at 5.5 mW/℃ for temperature above Ta=25℃,
mounted on 70mm×70mm×1.6mm 1 layer glass-epoxy PCB.
●Operation range
Parameter
VCC Power source voltage
DC/DC oscillation frequency
The effective range of ADIM signal
PWM input frequency range
Symbol
VCC
fsw
VADIM
FPWM
Ratings
20
VCC
7
20
VCC
687 (*1)
-40 to +85
150
-55 to +150
Range
9.0 to 18.0
50 to 800
0.2 to 3.5
90 to 100k
Datasheet
Unit
V
V
V
V
V
mW
℃
℃
℃
Unit
V
kHz
V
Hz
●Pin Configuration
●Package dimension, marking diagram
OVP
UVLO
SS
RT
PWM1
PWM2
FAILB
ADIM
ADIM_P
1
2
3
4
5
6
7
8
9
18 TC54
17 CS
16 FB
15 ISENSE
14 VCC
13 STB
12 GATE
11 DIMOUT
10 GND
BD9488F
Lot No.
Figure 3-1. Pin configuration
Figure 3-2. Package dimension
www.rohm.com
© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
2/38
TSZ02201-0F1F0C100040-1-2
27.May 2014 Rev.003
|