ꢀꢁꢁ ꢂ ꢃꢄ ꢅ ꢆ ꢀꢁꢁ ꢂ ꢃꢄ ꢇ ꢆ ꢀ ꢁꢁ ꢂꢃ ꢄꢄ
ꢀꢁꢁ ꢈ ꢃꢄ ꢅ ꢆ ꢀꢁꢁ ꢈ ꢃꢄ ꢇ ꢆ ꢀ ꢁꢁ ꢈꢃ ꢄꢄ
SLUS499A – NOVEMBER 2001 – REVISED JANUARY 2002
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FEATURES
DESCRIPTION
D
3-V to 13.5-V Operation
Liquid crystal display (LCD) enclosures and cold
D
Supports Flyback (UCC3975), Half-Bridge
(UCC3976), and Push-Pull (UCC3977)
Topologies
cathode fluorescent lamps (CCFLs) used in
notebook computer and portable electronics
displays are becoming increasingly narrow,
generating the need for a low profile CCFL power
supply. Recent advances in single- and
multi-layered piezoelectric ceramic transformers
(PZT) have enabled the development of a new
generation of efficient, size-reduced backlight
converters. The UCC3975/6/7 family of 8-pin PZT
controllers integrate the necessary circuitry for
operating a PZT-based backlight supply using a
flyback, half-bridge, or push-pull topology. The
choice of power topology depends on application
requirements such as input voltage, lamp voltage,
and PZT gain.
D
D
D
D
D
Programmable Voltage Controlled Oscillator
Open Lamp Protection
Low Shutdown Current (15-µA Typical)
Dual MOSFET Drivers
8-Pin TSSOP package
APPLICATIONS
D
D
D
Notebook Computers
Portable Electronics Displays
Portable Instruments
D
OPEN
SHUTDOWN
VDD
C
OPEN
R
OPEN
1
2
OPEN/SD
VDD
8
7
R
OSC
OUTP
HV
LRES
C
OSC
RANGE
UCC3976
R
OSC
R
3
COMP
OUTN
6
5
PIEZO
XFMR
C
CNT
FB
4
FB
GND
R
R
FB
D
FB
CCFL
CS
UDG–01092
Figure 1. UCC3976-Based CCFL Power Supply Using a Resonant Half-Bridge Topology
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Copyright 2002, Texas Instruments Incorporated
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ꢡ ꢥ ꢢ ꢡꢚ ꢛꢯ ꢝꢜ ꢠ ꢨꢨ ꢦꢠ ꢞ ꢠ ꢟ ꢥ ꢡ ꢥ ꢞ ꢢ ꢪ
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1
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