BL8549 Datasheet, PDF (1/6 Pages) SHANGHAI BELLING CO., LTD. – 40V Backlight LED Driver with PWM Direct Dimming

BL8549
40V Backlight LED Driver with PWM Direct Dimming
DESCRIPTION
The BL8549 is a high efficiency current-mode
asynchronous, 40V boost converter for LED
backlight driving. Its input voltage ranges from
2.5V to 4.5V and it provides an adjustable
constant current output decided by the Rset
connected to BL8549’s FB pin. The LED brightness
can also be controlled by a PWM signal directly
set to CE pin, making dimming control very
simple.
The BL8549’s switching frequency is set to
600KHz, and it will automatically switch between
PFM and PWM mode based on the load current,
thus to enhance the converter efficiency at light
load as well as heavy load.
BL8549 consists of many protection blocks such
as UVLO, output voltage over voltage protection,
and thermal protection to keep the chip and load
safe under unexpected environment.
The BL8549 is available in the tiny DFN2x2-6 and
SOT23-6 package.
FEATURES
 Adjustable Output Voltage, Vfb=0.2V
 Output voltage 40V, driving up to 12 LED string
 Range of operation input voltage: 2.5 – 4.5V
 Output Overvoltage Protection @40V
 CE pin PWM direct dimming function
 Line regulation: 0.1%/V (typ.)
 Load regulation: 10mV (typ.)
 High efficiency, up to 90% in driving 10 LEDs
 Environment Temperature: -20C~85C
APPLICATIONS
 Smartphone
 7” MID
 Portable DVD
 TFT LCD bias
 Portable LED lighting or torch
 Other application need high voltage
TYPICAL APPLICATION and PIN OUT
BL8549
Efficiency for Driving 10 LEDs
Efficiency VS Iout for 10 LEDs
100
95
90
85
80
75
70
65
60
Vin=3.6V
55
50
Vin=3.8V
45
Vin=4.2V
40
0
10
20
30
40
50
Output Current (mA)
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