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LIGHTING DRIVER. IS31LT3918 Datasheet

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LIGHTING DRIVER. IS31LT3918 Datasheet






IS31LT3918 DRIVER. Datasheet pdf. Equivalent




IS31LT3918 DRIVER. Datasheet pdf. Equivalent





Part

IS31LT3918

Description

HIGH VOLTAGE LED LIGHTING DRIVER



Feature


IS31LT3918 HIGH VOLTAGE LED LIGHTING DRI VER WITH SWITCH DIMMING OCTOBER 2011 GE NERAL DESCRIPTION IS31LT3918 LED driver IC is a peak current detection buck co nverter which operates in constant off time mode. It operates over a very wide input voltage supply range of 6VDC to 450VDC or 110VAC/220VAC. IS31LT3918 inc orporates the special feature of switch dimming by detect.
Manufacture

ISSI

Datasheet
Download IS31LT3918 Datasheet


ISSI IS31LT3918

IS31LT3918; ing OFF-ON cycles of the main power swit ch. When the switch is cycled within a 2 second period (typical) the device au tomatically switches the dimming level to the next step. As a result, dimming can be achieved without replacing any w iring in the original system. There are multiple modes of switch dimming that the user may configure 2 steps or 3 ste ps, as well as dif.


ISSI IS31LT3918

ferent levels of dimming via the externa l pins DIM1 and DIM2. IS31LT3918 can al so realize LED dimming using an externa l PWM signal. It can accept a PWM signa l from 0% to 100% duty cycle. The LED c urrent may also be adjusted linearly by applying an analog input voltage in th e range of 0.5V to 2.5V. IS31LT3918 ado pts a peak current mode control archite cture, which elimi.


ISSI IS31LT3918

nates the need for any additional loop c ompensation while maintaining a good de gree of constant output current regulat ion. TYPICAL APPLICATION CIRCUIT Switch K D1 85Vac- 265Vac D3 Fuse D2 R1 C1 D4 C2 R5 Q2 DZ D6 R2 VIN DIM1 Gate CS ADJ http://www.DataSheet4U.net/ FEATURES User configurable switch dimming levels 3% output current accuracy Over current, voltage .

Part

IS31LT3918

Description

HIGH VOLTAGE LED LIGHTING DRIVER



Feature


IS31LT3918 HIGH VOLTAGE LED LIGHTING DRI VER WITH SWITCH DIMMING OCTOBER 2011 GE NERAL DESCRIPTION IS31LT3918 LED driver IC is a peak current detection buck co nverter which operates in constant off time mode. It operates over a very wide input voltage supply range of 6VDC to 450VDC or 110VAC/220VAC. IS31LT3918 inc orporates the special feature of switch dimming by detect.
Manufacture

ISSI

Datasheet
Download IS31LT3918 Datasheet




 IS31LT3918
IS31LT3918
HIGH VOLTAGE LED LIGHTING DRIVER WITH SWITCH DIMMING
OCTOBER 2011
GENERAL DESCRIPTION
IS31LT3918 LED driver IC is a peak current detection
buck converter which operates in constant off time
mode. It operates over a very wide input voltage supply
range of 6VDC to 450VDC or 110VAC/220VAC.
IS31LT3918 incorporates the special feature of switch
dimming by detecting OFF-ON cycles of the main
power switch. When the switch is cycled within a 2
second period (typical) the device automatically
switches the dimming level to the next step. As a result,
dimming can be achieved without replacing any wiring
in the original system. There are multiple modes of
switch dimming that the user may configure 2 steps or
3 steps, as well as different levels of dimming via the
external pins DIM1 and DIM2.
IS31LT3918 can also realize LED dimming using an
external PWM signal. It can accept a PWM signal from
0% to 100% duty cycle. The LED current may also be
adjusted linearly by applying an analog input voltage in
the range of 0.5V to 2.5V.
IS31LT3918 adopts a peak current mode control
architecture, which eliminates the need for any
additional loop compensation while maintaining a good
degree of constant output current regulation.
FEATURES
User configurable switch dimming levels
3% output current accuracy
Over current, voltage and temperature protection
High efficiency (typical up to 95%)
Wide input voltage range: 6VDC~450VDC or
85Vac~ 265Vac
Linear and PWM dimming
Very few external components
APPLICATIONS
DC/DC or AC/DC constant current LED driver
Signal and decorative lighting
Backlight LED driver
TYPICAL APPLICATION CIRCUIT
Switch K
D1
85Vac- 265Vac
D3
Fuse
D2
C1
D4
R2
C6
C4
R1
C2
http://www.DataSheet4U.net/
R5
DZ
D6
D5 C3
L1
Q2
VIN Gate
DIM1
CS
IS3I1SL3T9319818
DIM2
ADJ
GND
TOFF
R6
R3
Q1
R4
LED+
LED-
Copyright © 2011 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time 
without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are advised 
to obtain the latest version of this device specification before relying on any published information and before placing orders for products. 
Integrated Silicon Solution, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the 
product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized 
for use in such applications unless Integrated Silicon Solution, Inc. receives written assurance to its satisfaction, that: 
a.) the risk of injury or damage has been minimized; 
b.) the user assume all such risks; and 
c.) potential liability of Integrated Silicon Solution, Inc is adequately protected under the circumstances
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 09/01/2011
1
datasheet pdf - http://www.DataSheet4U.net/




 IS31LT3918
IS31LT3918
PIN CONFIGURATION
Package
SOP-8
Pin Configurations
PIN DESCRIPTION
Pin Name
DIM1
DIM2
ADJ
GND
GATE
CS
Toff
Vin
Pin Number
1
2
3
4
5
6
7
8
Description
These two pins configure the dimming levels as follows:
DIM1=“floating”DIM2=“floating”, no dimming (100% only)
DIM1=“floating”DIM2=“GND” , 100%-30%-100%
DIM1=“GND”DIM2=“floating”, 100%-50%-100%
DIM1=“GND”DIM2=“GND”, 100%-50%-20%-100%
Linear and PWM dimming input pin.
Linear dimming range: 0.5V to 2.5V.
If VADJ < 0.5V, GATE output is off.
If 0.5V VADJ 2.5V, VCSTH = VADJ/10.
If VADJ > 2.5V, VCSTH = 0.25V.
When this pin is floating, there is an internal pull up to 4.5V (typical) and VCSTH = 0.25V.
PWM dimming frequency range: 200Hz -1kHz.
Ground pin. All internal currents return through this pin.
This pin connects to the external NMOS’s gate
Current detect pin, uses an external resistor to sense the peak inductor current.
This pin sets the off time for the switch by connecting a resistor between this pin and
GND.
http://www.DataSheet4U.net/
8V – 450V supply voltage is connected to this pin via an external resistor. It is internally
clamped and must be bypassed using a capacitor to GND.
ORDERING INFORMATION
INDUSTRIAL RANGE: -40°C TO +85°C
Order Part No.
Package
IS31LT3918–GRLS2-TR SOP-8, Lead-free
QTY/Reel
2500
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 09/01/2011
2
datasheet pdf - http://www.DataSheet4U.net/




 IS31LT3918
IS31LT3918
ABSOLUTE MAXIMUM RATINGS
Parameter
Range
Unit
Vin pin to GND
DIM1,DIM2,CS, ADJ, GATE, Toff pin to GND
-0.3 – 6.0
-0.3 - 6.0
V
V
Vin pin input current (Note1)
10 mA
Junction temperature
-40 – 150
Device storage temperature
-65 - 150
ESDHuman Body model
3500
V
Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(The specifications are at TA=25°C and VINDC=10V (Note 2), RIN =10K, unless otherwise noted)
Symbol
Parameter
Vclamp
Vin PIN clamp voltage
UVLO Undervoltage lockout
UVLO UVLO hysteresis
IIN
IIN,UV
VCSTH
TBLANK
Toff
VADJ
(Note 3)
Quiescent Current
Input current in UVLO
Current sense threshold
Current sense blanking time
Off time
PWM input voltage high threshold
PWM input voltage low threshold
Linear dimming input voltage range
Conditions
Min Typ Max Unit
Supply voltage connected to
Vin via an appropriate resistor
4.3
5
5.5
V
Vin rising
4.8 V
400 mV
Vin=5V
300 400 uA
Vin=4V
90 120 uA
ADJ=5V
http://www.DataSheet4U.net/
VCS=VCSTH+50mV
REXT=250K
245 250 255
445 500 650
9.8 10 10.2
2.5
mV
ns
us
V
0.25 0.5 0.75 V
0.5 2.5 V
ISOURCE GATE source current
GATE=0
75 90
ISINK GATE sink current
GATE=5V
75 90
TP Over temperature protection threshold
150
TP
VOCP
Over temperature protection hysteresis
Over current protection CS voltage
threshold
ADJ=5V,CS rising
20
0.35 0.4 0.45
Toff_reset Over current protection Toff delay time
500
TMAX
Maximum switch off time for switch
dimming
2
Notes:
1. Beyond the input current range, Vin pin may not clamp at 5V.
2. VIN is the input voltage. When VIN>5V, input voltage connected to Vin pin should via a appropriate resistor.
3. When VADJ>2.5V, Iout is 100% output current. When VADJ<0.5V, Iout is shutdown. When 0.5V VADJ2.5V, Iout is linear dimming.
mA
mA
oC
oC
V
us
s
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 09/01/2011
3
datasheet pdf - http://www.DataSheet4U.net/



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