OB3309
Highly Integrated U Type CCFL Backlight Controller
Product Specification
FEATURES
GENERAL DESCRIPTION
High performance push pull topology
Optimized for U type CCFL solution
Adjustable dimming polarity
OB3309 is
a
highly integrated and high
performance U-type Cold Cathode Fluorescent
Lamp (CCFL) controller optimized for LCD display
backlight application. Comprehensive protection
functions are integrated, thus it provides a cost
effective yet high reliability LCD backlight solution.
Adjustable striking frequency & time
Flexible Dimming mode Control:
| Analog dimming control
Operating in push pull configuration, OB3309
converts DC input voltage to the pure sinusoidal
voltage and current waveforms, to ignite and
operate CCFL lamps.
| Internal burst dimming control
| External burst (LPWM) dimming control
Adjustable minimum duty for internal burst
dimming
It provides a high degree of design flexibility by
offering great programmability for key parameters
which include operating frequency, striking
frequency, striking time, dimming polarity, burst
dimming frequency, soft-start time, and soft on/off
time for burst dimming.
Adjustable minimum reference voltage for
analog dimming
0-2V DC voltage direct dimming control
without external circuits
Comprehensive Protection Coverage:
| Output over voltage protection (OVP)
| Output over current protection (OCP)
Various dimming modes control and dimming
polarity programmability are offered. Both internal
burst and external low frequency PWM (LPWM)
dimming methods are available for a wide range of
dimming control. Analog dimming is also provided
through external DC input control to achieve wide
dimming range.
| Open lamp protection and short lamp
protection
| Arcing protection
APPLICATIONS
The highly integrated OB3309 provides complete
protection features covering output over voltage,
over output current protection, lamp fail safe
function, and IC under voltage lockout.
LCD Monitor
LCD TV
Flat panel display
The OB3309 is available in SOP-16 Packages.
TYPICAL APPLICATION
VIN
DIM
VS
1
16
15
ENA
DIM
STIME
CMP
CS
ENA
2
3
4
5
6
7
RI
14
13
12
11
10
9
RT
DRC
BF/DMOD
POL
PRT
PRT
PRT
VS
VS
VDD
GATE1
GND
GATE2
8
+5V
VS
OB3309
GND
Figure1. OB3309 Typical Application Schematic
©On-Bright Electronics
Confidential
Preliminary Datasheet
OB_DOC_DS_330900
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