LX1691
TM
庐
Enhanced Multi-Mode CCFL Controller
P
RODUCTION
D
ATA
S
HEET
DESCRIPTION
KEY FEATURES
WWW .
Microsemi
.C
OM
Microsemi鈥檚 LX1691 is a cost
reduced, enhanced feature set, Direct
Drive CCFL (Cold Cathode Fluorescent
Lamp) Controller. Its architecture is
based on the very popular LX1689. By
limiting V
DDP
to 5.5V and using
advanced processing, die size and
package pin count is decreased while
improving dimming precision.
LX1691 based inverter modules can
be designed for virtually any CCFL
appliance from digital cameras and
PDA鈥檚 to big screen monitors and
driver viewable automotive displays.
New versatile dimming circuitry can
accept digital and analog control inputs
and provides six different dimming
modes that control both lamp current
amplitude and duty cycle, either simul-
taneously or separately. Designers can
select normal or reverse polarity
dimming and precisely program mini-
mum and maximum lamp currents with
resistors. The LX1691 fault shutdown
feature is enhanced to include regu-
lation and shutdown for over voltage
and over current conditions.
Microsemi鈥檚 proven and patented
Direct Drive architecture works with
system voltages from 3 volts to more
than 50 volts, limited only by the
external power FET鈥檚 that drive the high
voltage transformer.
The LX1691 includes the Microsemi
proven and patented strike method that
allows significant efficiency gains while
guaranteeing strong striking power at all
operating temperatures. Our method
sweeps
strike frequency smoothly up to
the unloaded resonant frequency of the
lamp and high voltage transformer.
This, coupled with the LX1691鈥檚 active
high output voltage regulation, produces
just enough strike voltage without
generating unpredictable high voltage
spikes that cause arcing and component
failures. Competitive devices that
simply
switch
to a higher frequency for
striking do not have this 鈥渞eal time鈥?/div>
control over output voltage, and require
much more attention to transformer
design.
Simultaneous Amplitude And
Duty Cycle Dimming Modes
Resistor Programmable Min and
Max Lamp Currents
Digital Dimming Can Synch To
External Or Internal Clocks
100 ms Power On Delay
Open Or Shorted Lamp
Regulation & Shutdown
鈥淥n Chip鈥?Full Wave Lamp
Current & Voltage Rectifiers
16 Pin TSSOP Package
Very Stable Oscillator with On-
Chip Timing Capacitor
Soft Start-Up Striking
Enhanced Digital Dimming
Resolution
BENEFITS
Low Component Count / Module
Cost / And Size
High 鈥淣its/Watt鈥?Efficiency
Operates Directly From a Single
Li-Ion Cell
Industries Safest And Highest
Performing Strike Voltage
Generation (Patented)
Tight Operating Frequency
Tolerance For Easier System
Level RFI Control
IMPORTANT:
For the most current data, consult
MICROSEMI鈥檚
website:
//www.microsemi.com
PRODUCT HIGHLIGHT
Traditional Analog
2
Lamp Current (mA)
+
External Digital
2
Lamp Current (mA)
+
BRITE_IN
+3V
T2
BRITE_IN
VDC
0
T1
DD_CLK
T1
VDC
0
_
T2
T
DD_CLK
T = 512 / DD_CLK Frequency
T
_
Internal Digital
2
Lamp Current (mA)
+
Direct PWM (Analog)
2
Lamp Current (mA)
BRITE_IN
+3V
T
+
BRITE_IN
VDC
0
VDC
LX1691
LX1691
DD_CLK
T
_
0
T1
T2
DD_CLK
T1
T = 512 / Lamp Frequency
_
T2
Four of Six Dimming Modes
PACKAGE ORDER INFO
T
A
(掳C)
-40 to +85
M
IN
V
DDP
2.8V
M
AX
V
DDP
5.5V
PW
Plastic TSSOP
16-PIN
LX1691IPW
Pb-free
Note: Available in Tape & Reel. Append the letters 鈥淭R鈥?to the part number. (i.e. LX1691IPWTR)
Copyright
漏
2003
Rev. 1.0, 7/16/2004
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
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