Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF


OZ964GN Datasheet(PDF) 8 Page - List of Unclassifed Manufacturers

Part No. OZ964GN
Description  Change Summary
Download  14 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  ETC2 [List of Unclassifed Manufacturers]
Homepage  
Logo 

 8 page
background image
OZ964
CONFIDENTIAL
OZ964-DS-1.2
Page 7
FUNCTIONAL INFORMATION
1. Steady-State Operation
Referring to the example schematic shown in
Figure 2, page 9, OZ964 drives a full-bridge
power train where the transformer couples the
energy from the power supply source to the
CCFL. The switches in the bridge denoted as
QA, QB, QC and QD are configured such that the
transistors in each pair, QA/QB and QC/QD, are
turned-on complementarily. The turn-on duration
of the diagonal switches, QA/QD and QB/QC,
simultaneously determines the amount of energy
delivered to the transformer and subsequently to
the CCFL. The current in the CCFL is sensed
and regulated by adjusting the turn-on time
(overlap) for both diagonal switches. This is
accomplished through an error amplifier in the
current feedback loop.
A voltage loop is used to regulate the output
voltage for CCFL ignition and is programmable
by using a capacitor divider (C8/C13).
Over Voltage Protection (OVP) limits the
transformer
voltage
under
an
open-lamp
condition. A soft-start circuit ensures a gradual
increase in power to the CCFL. The soft-start
capacitor (C9) determines the rate of rise of the
voltage on the SST pin. Meanwhile, the voltage
level determines the turn-on time of the diagonal
switches QA/QD and QB/QC.
The output drives for the power MOSFET gates
include PDR_A, NDR_B, PDR_C and NDR_D
that output a complementary square pulse. The
operation of the four switches is implemented
with zero-voltage switching that provides a high-
efficiency power conversion.
2. Enable
OZ964 is enabled when the voltage on ENA (pin
3) is greater than 2V. A voltage of less than 1V
disables the IC. When the inverter controller is
disabled, it draws approximately 200uA. An
under-voltage
lockout
protection
feature
is
provided that will disable the IC if VDDA voltage
drops below an ~3.4V threshold. The IC will
resume normal operation once VDDA reaches a
threshold voltage of greater than ~4.3V.
3. Soft-Start
To avoid component stresses and in-rush current
to the CCFLs during ignition, a soft start function
is
implemented
to
provide
reliable
CCFL
operation. The soft-start function is initiated when
the voltage at ENA (pin 3) is greater than 2V. The
soft-start time is determined by an external
capacitor (C9) connected to the SST (pin 4). At
start-up, as C9 charges via a charging current,
the voltage level at the capacitor controls the
gradual increase in power delivered to the
transformer T1.
4. Ignition
The OZ964 provides an option of selecting a
different frequency for striking the CCFLs. The
striking time is user-defined and determined by
an external capacitor CCTIMR (C6) and external
resistor RCTIMR (R5) connected to CTIMR (pin 1).
The approximate striking time is determined by
the following equation.
CCTIMR[µF] x (3-(RCTIMR[kΩ] x 0.0026))
T[second] =
2.6
The approximate striking frequency is determined
by the following equation.
65
•104
fstriking[kHz] =
CCT[pF]•(RRT // RRT1) [kΩ]
Note: RRT // RRT1 means RRT is in parallel with RRT.1.
5. Normal Operation
Once the IC is enabled, the voltage at SST (pin
4) controls the rate of power delivered to the
load. SST voltage increases to a level such that
the CCFLs are ignited. The striking frequency is
determined by external components R10, R9 and
C5 connected to RT1 (pin 8), RT (pin 17) and CT
(pin 18) respectively.
Once the external resistor R16 senses sufficient
current, the control loop takes control and
regulates
the
CCFL
current.
The
normal
operating frequency is determined by the
combination of external resistor R9 and external
capacitor C5. The operating frequency is
approximated by the following equation.
65
•104
fop[kHz] =
CCT[pF]•RRT[kΩ]




Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14 


Datasheet Download



Related Electronics Part Number

Part NumberComponents DescriptionHtml ViewManufacturer
ML9XX11_04Notice : Some parametric limits are subject to change InGaAsP DFB LASER DIODES 1 2 3 4 Mitsubishi Electric Semiconductor
VTD170+85 °C to -40 °C 10 times ±5 % typical resistance change 1 2 Littelfuse
DCS-1078PRODUCT CHANGE NOTICE 1 2 3 4 5 MoreDiodes Incorporated
AT76C901Wireless VoIP Phone-based on the 802.11 Standard Processor AT76C901 Summary 1 2 3 4 ATMEL Corporation
AT78C7015Spindle/VCM Motor Controller/Drivers AT78C7015 Summary 1 2 3 4 5 ATMEL Corporation
MPC859TTSPowerQUICC™ Family Technical Summary 1 2 3 4 5 MoreMotorola, Inc

Link URL

Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Bookmark   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  , Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp  |   Russian : Alldatasheetru.com
Korean : Alldatasheet.co.kr   |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com  |   Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl