Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.NET

X  

LT3492IFETRPBF Datasheet(PDF) 9 Page - Linear Technology

Part # LT3492IFETRPBF
Description  Triple Output LED Driver with 3000:1 PWM Dimming
Download  20 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  LINER [Linear Technology]
Direct Link  http://www.linear.com
Logo LINER - Linear Technology

LT3492IFETRPBF Datasheet(HTML) 9 Page - Linear Technology

Back Button LT3492IFETRPBF Datasheet HTML 5Page - Linear Technology LT3492IFETRPBF Datasheet HTML 6Page - Linear Technology LT3492IFETRPBF Datasheet HTML 7Page - Linear Technology LT3492IFETRPBF Datasheet HTML 8Page - Linear Technology LT3492IFETRPBF Datasheet HTML 9Page - Linear Technology LT3492IFETRPBF Datasheet HTML 10Page - Linear Technology LT3492IFETRPBF Datasheet HTML 11Page - Linear Technology LT3492IFETRPBF Datasheet HTML 12Page - Linear Technology LT3492IFETRPBF Datasheet HTML 13Page - Linear Technology Next Button
Zoom Inzoom in Zoom Outzoom out
 9 / 20 page
background image
LT3492
9
3492f
is similar to your application and tune the compensation
network to optimize the performance. The stability, PWM
dimming waveforms and the start-up time should be
checked across all operating conditions.
Open-LED Protection
The LT3492 has open-LED protection for all the three
converters. As shown in Figure 1, the OVP1 pin receives
the output voltage (the voltage across the output capacitor)
feedback signal from an external resistor divider. OVP1
voltage is compared with a 1V internal voltage reference by
comparator A6. In the event the LED string is disconnected
or fails open, converter 1 output voltage will increase, caus-
ing OVP1 voltage to increase. When OVP1 voltage exceeds
1V, the power switch Q1 will turn off, and cause the output
voltage to decrease. Eventually, OVP1 will be regulated to
1V and the output voltage will be limited. In the event one
of the converters has an open-LED protection, the other
converters will continue functioning properly.
Switching Frequency and Soft-Start
The LT3492 switching frequency is controlled by FADJ
pin voltage. Setting FADJ voltage to be less than 1V will
reduce switching frequency.
If FADJ voltage is higher than 1V, the default switch-
ing frequency is 2.1MHz. In general, a lower switching
frequency should be used where either very high or very
low switch duty cycle is required or higher efficiency is
desired. Selection of a higher switching frequency will
allow use of low value external components and yield a
smaller solution size and profile.
As a cautionary note, operation of the LT3492 at a com-
bination of high switching frequency with high output
voltage and high switch current may cause excessive
internal power dissipation. Consideration should be given
to selecting a switching frequency less than 1MHz if these
conditions exist.
Connecting FADJ pin to a lowpass filter (R5 and C4 in
Figure 1) from the REF pin provides a soft-start function.
During start-up, FADJ voltage increases slowly from 0V
to the setting voltage. As a result, the switching frequency
increases slowly to the setting frequency. This function
limits the inrush current during start-up.
Input Capacitor Selection
For proper operation, it is necessary to place a bypass
capacitor to GND close to the VIN pin of the LT3492. A
1μF or greater capacitor with low ESR should be used. A
ceramic capacitor is usually the best choice.
In the buck mode configuration, the capacitor at PVIN has
large pulsed currents due to the current returned though
the Schottky diode when the switch is off. For the best
reliability, this capacitor should have low ESR and ESL
and have an adequate ripple current rating. The RMS
input current is:
I
IN(RMS) = ILED •1– D
()•D
where D is the switch duty cycle. A 1μF ceramic type ca-
pacitor placed close to the Schottky diode and the ground
plane is usually sufficient for each channel.
Output Capacitor Selection
The selection of output filter capacitor depends on the load
and converter configuration, i.e., step-up or step-down.
For LED applications, the equivalent resistance of the LED
is typically low, and the output filter capacitor should be
large enough to attenuate the current ripple.
To achieve the same LED ripple current, the required filter
capacitor value is larger in the boost and buck-boost mode
applications than that in the buck mode applications. For
the LED buck mode applications at 1.3MHz, a 0.22μF ce-
ramic capacitor is usually sufficient for each channel. For
the LED boost and buck-boost applications at 1.3MHz, a
1μF ceramic capacitor is usually sufficient for each chan-
nel. Lower switching frequency requires proportionately
higher capacitor values. If higher LED current ripple can
be tolerated, a lower output capacitance can be selected
to reduce the capacitor’s cost and size.
Use only ceramic capacitors with X7R or X5R dielectric,
as they are good for temperature and DC bias stability of
the capacitor value. All ceramic capacitors exhibit loss of
capacitance value with increasing DC voltage bias, so it
may be necessary to choose a higher value capacitor to get
the required capacitance at the operation voltage. Always
check that the voltage rating of the capacitor is sufficient.
Table 1 shows some recommended capacitor vendors.
APPLICATIONS INFORMATION


Similar Part No. - LT3492IFETRPBF

ManufacturerPart #DatasheetDescription
logo
Linear Technology
LT3492 LINER-LT3492 Datasheet
441Kb / 24P
   60V Triple Step-Down LED Driver Programmable Temperature Protection
logo
Analog Devices
LT3492 AD-LT3492 Datasheet
2Mb / 36P
   I2C Programmable Quad Monolithic Boost LED Driver
logo
Linear Technology
LT3492 LINER-LT3492_15 Datasheet
335Kb / 22P
   Triple Output LED Driver with 3000:1 PWM Dimming
More results

Similar Description - LT3492IFETRPBF

ManufacturerPart #DatasheetDescription
logo
Linear Technology
LT3492 LINER-LT3492_15 Datasheet
335Kb / 22P
   Triple Output LED Driver with 3000:1 PWM Dimming
logo
Lowpower Semiconductor ...
LP3350 POWER-LP3350 Datasheet
324Kb / 7P
   LED Driver with PWM Dimming Control
logo
Princeton Technology Co...
PT6989 PTC-PT6989 Datasheet
279Kb / 4P
   BUCK LED DRIVER WITH PWM DIMMING
logo
ON Semiconductor
CAT4101TV-T75 ONSEMI-CAT4101TV-T75 Datasheet
158Kb / 11P
   1 A Constant-Current LED Driver with PWM Dimming
Doc. No. MD-5036, Rev. D
CAT4101 ONSEMI-CAT4101 Datasheet
159Kb / 10P
   1 A Constant-Current LED Driver with PWM Dimming
February, 2010 ??Rev. 4
logo
E-CMOS Corporation
EC4215 E-CMOS-EC4215 Datasheet
257Kb / 6P
   Constant Current LED Driver with PWM Dimming
logo
Renesas Technology Corp
ISL97632 RENESAS-ISL97632 Datasheet
508Kb / 10P
   LED Driver with 1-Wire Dimming
logo
Intersil Corporation
ISL97632 INTERSIL-ISL97632_10 Datasheet
175Kb / 9P
   LED Driver with 1-Wire Dimming
logo
ON Semiconductor
LV52207XA ONSEMI-LV52207XA Datasheet
3Mb / 18P
   Dual channel LED Boost Driver with PWM and 1-Wire Dimming
June, 2014
logo
New Japan Radio
NJW4615A NJRC-NJW4615A Datasheet
70Kb / 4P
   Constant Current LED Driver with PWM Dimming Control
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.NET
Does ALLDATASHEET help your business so far?  [ DONATE ] 

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


Mirror Sites
English : Alldatasheet.com  |   English : 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  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com