|
|
PDF LX1691 Data sheet ( Hoja de datos )
| Número de pieza | LX1691 | |
| Descripción | Enhanced Multi-Mode CCFL Controller | |
| Fabricantes | Microsemi Corporation | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LX1691 (archivo pdf) en la parte inferior de esta página. Total 15 Páginas | ||
|
No Preview Available !
www.DataSheet4U.com
TM
LX1691
® Enhanced Multi-Mode CCFL Controller
PRODUCTION DATA SHEET
DESCRIPTION
Microsemi’s 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 VDDP 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’s 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’s 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’s 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’s 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 “real time”
control over output voltage, and require
much more attention to transformer
design.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
KEY FEATURES
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
“On Chip” 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 “Nits/Watt” 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
Traditional Analog
2 BRITE_IN
PRODUCT HIGHLIGHT
Lamp Current (mA)
+
External Digital
2 BRITE_IN
Lamp Current (mA)
+
+3V
0
T1
T2 DD_CLK
Internal Digital
2 BRITE_IN
+3V
0
T
DD_CLK
T = 512 / Lamp Frequency
_
T1 T2
Lamp Current (mA)
+
0
T
DD_CLK
T = 512 / DD_CLK Frequency
Direct PWM (Analog)
2 BRITE_IN
_
T
Lamp Current (mA)+
_
T
0
T1
T2 DD_CLK
Four of Six Dimming Modes
T1
_
T2
Copyright © 2003
Rev. 1.0, 7/16/2004
PACKAGE ORDER INFO
TA (°C)
MIN VDDP
PWMAX VDDP
Plastic TSSOP
16-PIN
-40 to +85
2.8V
5.5V
LX1691IPW
Pb-free
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1691IPWTR)
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
1 page  
LX1691
TM ® Enhanced Multi-Mode CCFL Controller
PRODUCTION DATA SHEET
RECOMMENDED OPERATING CONDITIONS
Parameter
Supply Voltage (VDDP)
Digital Input (ENABLE)
Analog Inputs (I_SNS, OC_SNS, OV_SNS)
BRITE_IN Linear DC Voltage Range
BRITE_OUT, BRITE_R Maximum Source Current
Digital Inputs (DIM_MODE, DD_CLK)
Internal Oscillator Frequency (I_R Resistor Range 42K to 175K)
Maximum Output Gate Charge (AOUT, BOUT)
LX1691
Min Typ
2.8
0
-2
0
0
60
10
Max
5.5
5.5
2
2
100
5.5
250
20
Units
V
V
VPK
V
µA
V
KHz
nC
ELECTRICAL CHARACTERISTICS (CONTINUED)
Unless otherwise specified, the following specifications apply over the operating ambient temperature -40°C ≤ TA ≤ 85°C except where
otherwise noted. Test conditions: VDDP =3.3 to 5.5 V, I_R =80.6KΩ, BRITE_R = BRITE_OUT = 20KΩ, OVSNS = OCSNS = 0V,
DD_CLK = DIM_MODE = Floating
Parameter
` POWER
Power Supply Input Voltage
Regulator Output Voltage
VDDA Drop Out Voltage
VDDP Operating Current
Sleep Mode Current
` ENABLE INPUT
Run Threshold
Shutdown Threshold
Input High Current
Input High Current
Input Low Current
` UNDER VOLTAGE LOCKOUT
Startup Threshold
UVLO Threshold
UVLO Hysteresis
` BIAS BLOCK
Voltage at Pin I_R
Pin I_R Max Source Current
Voltage Reference Voltage
(Internal node)
` OUTPUT BUFFER BLOCK
Output Sink Current
Output Source Current
Symbol
Test Conditions
V_BATT
VDDA
VDROPOUT
IBB
IDD_SLEEP
VDDP= 3.3 to 5.5V, I Load = 0 mADC
I Load = 0 mADC
CAOUT = CBOUT = 1000pF; fOSC = 130kHz
VENABLE = 0.8V, VDDP = 5.5V
VTH_ENRUN
VTH_ENSHDN
IIH_ENABLE
IIH_ENABLE
IIL_ENABLE
ENABLE = 2V
ENABLE = 5V
ENABLE = 0V
VTH_UVLO
VH_UVLO
Run Mode
Shutdown Mode
V_IR
IMAX_IR
V2P0
80.6K
ISK_OUTBUF
IS_OUTBUF
VAOUT, VBOUT = VDDP
VAOUT, VBOUT = 0V
LX1691
Units
Min Typ Max
2.8 5.5 V
2.85 3.0 3.15
V
50 150 mV
10 15 mA
10 µA
1.5 2.8
V
0.8 1.1
V
2 12 µA
35 80 µA
-1 0 1 µA
2.55 2.8
V
2.1 2.35
200 mV
0.975
1.025
V
100 µA
1.98 2.02 V
100 mA
100 mA
Copyright © 2003
Rev. 1.0, 7/16/2004
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
5 Page 
LX1691
TM ® Enhanced Multi-Mode CCFL Controller
PRODUCTION DATA SHEET
DETAILED DESCRIPTION (CONTINUED)
LX1691 Operation
Four operating modes: Power On Delay, Strike, Run, and Fault
modes are employed by the LX1691. Upon power up or ENABLE
going true, Power On Delay is automatically invoked.
Immediately after termination of Power On Delay, or ENABLE
going true, strike mode is entered. After a successful strike, e.g.,
lamp is ignited, run mode is entered. If ignition is unsuccessful, or
if the lamp extinguishes while running, Fault mode is entered.
Lamp ignition is determined by monitoring the lamp current
feedback voltage at pin I_SNS. Lamp current cycles are counted
from the beginning of Strike mode. If 4 or more complete cycles
occur the lamp is declared ignited. If less than 4, the lamp is
considered not ignited and Strike mode continues until ignition is
detected or strike time out (approximately 350ms) is reached.
After run mode is entered lamp current pulse count is sampled
several times a second to determine that the lamp has not
inadvertently extinguished. If lamp current pulses are counted in
each sample, Run mode is maintained. Otherwise, Fault mode is
entered. Strike mode can be entered only once for each on/off cycle
of either VDDP or ENABLE. This insures that even intermittent
lamp failures cannot cause the module to continuously output
maximum strike voltage.
During strike, operating frequency is swept from the normal run
value approximately to 3X run frequency. This will excite the
unloaded resonant frequency of the transformer and lamp load to
generate the required lamp striking voltage. If the lamp has not
ignited after about 350mS, a fault is declared and the A & B
outputs are shut off.
If while strike frequency is sweeping, the over voltage set point
at OV_SNS is detected or overcurrent voltage set point at
OV_SNS is deteted the, strike frequency will hold at the frequency
value until either the lamp strikes or the timeout is reached. This
causes maximum strike potential to be continuously impressed
across the lamp for the entire strike period.
Also, if while strike frequency is sweeping, the over current set
point at OC_SNS is detected, strike frequency will hold at the
present value until either the lamp strikes or the timeout is reached.
This insures short circuit current regulation will be maintained, thus
enabling UL fault requirements to be easily met at the inverter
module level.
The only way to re-initiate the strike process is to either cycle
VDDP or ENABLE off and on.
If ignition is successful, ramp frequency immediately returns to
its programmed run value.
Power ON Delay Mode
All functions are activated except that AOUT and BOUT are
inhibited. Delay is in the 100mSec range and is determined by a
counter. Power on delay is activated at every VDDP power up
sequence and ENABLE sequence.
Strike Mode
Entered from Power On Delay, or upon an ENABLE sequence.
Control of the Ramp Generator frequency is switched to the DAC
output. Frequency is increased from its normal run value to up to
three times that value for up to 6 sweeps If while strike frequency is
sweeping, the set points at OV_SNS and / or OC_SNS are detected,
strike frequency will freeze at the present value until either the lamp
strikes or the timeout is reached. Strike Mode is terminated by
reaching 6 sweep counts or by detecting lamp ignition. If strike is
successful, Run Mode is entered. If unsuccessful, Fault mode is
entered.
Run Mode
Entered only by detection of a successful Strike. Frequency
control is immediately switched to a fixed reference that sets the
programmed run frequency. The lamp current cycle counter is
monitored to insure at least 4 current cycles received during each
period. If less than 4, the lamp is considered extinguished and the
Fault Mode is entered.
Fault Mode
Fault Mode may be entered from either Strike or Run Mode as
described above. In Fault Mode, the A & B output buffers are
forced low. Fault mode may be cleared by cycling ENABLE off
then on, or by removing and applying VDDP.
Design Procedure
Selecting the I_R resistor value
This resistor determines the value of several internal reference
currents that control timing. It must be chosen first, and will be in
the range of 40 to 120K ohms. We use an 80.6K, 1% low TCR
value in our designs to set nominal lamp current frequency to
65kHz. The output frequency is approximated by the following
formula: RI_R = 5.24E9 / FLAMPOUT/HZ.
Driving the BRITE_IN Input
The BRITE_IN input circuitry includes on-chip active voltage
clamps that ignore input voltage greater than 2.0V. Input
impedance is very high so it can also be driven from a 100K
potentiometer with no offset error. BRITE_IN can be a DC voltage,
or a higher frequency externally filter PWM The BRITE_IN input
has a linear active range between 0.0 and 2.0V
Copyright © 2003
Rev. 1.0, 7/16/2004
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 11
11 Page | ||
| Páginas | Total 15 Páginas | |
| PDF Descargar | [ Datasheet LX1691.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LX1691 | Enhanced Multi-Mode CCFL Controller | Microsemi Corporation |
| LX1691A | Enhanced Multi-Mode CCFL Controller | Microsemi Corporation |
| LX1691B | Enhanced Multi-Mode CCFL Controller | Microsemi Corporation |
| LX1692 | Full Bridge Resonant CCFL Controller | Microsemi Corporation |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |