鈥?/div>
Single-stage power conversion
Constant frequency design eliminates inter-
ference with LCDs
Built-in open-lamp protection and short-
circuit protection
Reliable 2-winding transformer design elimi-
nates arcing failures and the need for fold-
back wiring
32-level dimming and 256-level contrast
control via SMBus
High efficiency, 90% typical
Supports both floating secondary and
grounded secondary designs
GENERAL DESCRIPTION
The OZ968 is a unique single-stage, high-
efficiency, CCFL backlight controller. It drives a
zero-voltage-switching circuit and provides a
near sinusoidal output voltage and current wave-
forms for a CCFL backlight. Typical operating
frequency ranges from 30KHz to 100KHz. These
advances drive the OZ968 beyond comparable
conventional inverter designs with two power
conversion stages (one operates at a variable
frequency, the other at a constant frequency).
Operating in a PWM push-pull drive, the trans-
former in an OZ968 backlight inverter requires
only one primary winding and one secondary
winding. The secondary winding requires no fold-
back treatment.
The OZ968 supports a bi-directional, two-wire
bus, data transmission protocol to control dim-
ming (32 levels) and contrast (256 levels). Sup-
ply current is 1mA in active mode, 150碌A(chǔ) in
standby mode.
The OZ968 is available in a 16-pin SOP pack-
age. It is specified over the commercial tempera-
ture range 0oC to +70oC.
ORDERING INFORMATION
OZ968G
- 16-pin plastic SOP
TYPICAL APPLICATION CIRCUIT
20V
SMBCLCK
SMBDATA
ENABLE
5V
CONTRAST
OZ968
C5
1:40
C6
0.1u
22p/3KV
Q4
3904
CCFL
Q2
Si4559EY/P
D1
C1
47u/
25v
1
C2
FB
VDD
16
R3
3.3k
2
0.1u
CMP
SCP
15
C3
0.47u
3
SST
VSEQ
14
4
ADJ
SMBD
13
R6
2.2k
R4
200k
Q3
3906
C7
1N4148
D2
1N4148
5
CNT
SMBC
12
4.7u
6
RT
OVP
11
R8
Q1
Si4559EY/
N
7
R2
120k
C4
220p
CT
PDR
10
10k
Q5
3904
R5
10k
R7
0.1ohm
R10
100k
R9
1k
8
GND
NDR
9
Figure 1. Typical Application Circuit
06/15/00
餂?/div>
Copyright 1999 by O
2
Micro
OZ968-SF-1.5
All Rights Reserved
Page 1
U.S. Patent #5,619,402
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