LT3799 – create a LED driver with an active PFC

Isolated offline-flyback controller LT3799 enables to create a powerful LED driver with a minimum of external components, which is moreover compatible with common triac dimmers.

This is an archive article published 04/12/2012. Some information may no longer be up to date and in line with the current state. Please contact us in case of interest.

At the design of a new LED driver, we usually have to consider more factors like for example an output current stability, shortcut or open LED protection, efficiency, safety (isolated secondary circuit form the primary one), power factor correction, EMI, number of external components and other.

LT3799 meets all these requirements and offers another benefits, like for example a possibility to use a smaller transformer thanks to the use of critical conductivity mode, powerful external MOSFET driver, internal LDO regulator and also a very good output current regulation – typically +-5%, moreover with no opto-isolator. A big bonus is the active power factor correction, thanks to which it reaches typical values of 0,96 (at 230V AC), thus meeting the most stringent requirements in this field, as well as IEC 61000-3-2 class C about harmonic currents emission. When we look closer at the recommended application circuit, we´ll find out that behind a diode bridge we won´t find any (otherwise common) input electrolytic capacitor with value of tens or hundreds of uF. That´s why the input voltage of the controller and a of the power transformer “copies” input sinusoid. Excellent power factor is reached just thanks to it, that LT3799 knows immediate input voltage value and based on this value, it sets the input current limit (in a given cycle of the SMPS), proportionally to the immediate value of the input AC voltage. Further LT3799 gains information about the immediate current from the primary side, that´s why it doesn´t require an opto-coupler. Thanks to this, LT3799 works like a current source in every period of input voltage, that´s why it is even possible to use classic triac regulators, which are often already a part of the buildings installation. In other words – LT3799 doesn´t try to compensate “dropouts” in power supply caused by a phase control of a triac, what causes decreasing of an output LED current and their fluent dimming. Neither this control method doesn´t cause LED blinking, because there is an electrolytic capacitor on the transformer output.

Detailed information you can find in the LT3799 datasheet and in the Design Note 490. For the development support is also available the LT3799 demo board DC1595A. In case of interest about any Linear Technology, please contact us at info@soselectronic.com.

LT3799 – create a LED driver with an active PFC

Videos

Advantages / Features:

  • universal isolated offline flyback controller for LED drivers
  • suitable for 4-100W+ power
  • active power factor correction (PFC), 0.96/230V AC typically
  • dimmable by common triac regulators
  • low harmonic content, IEC 61000-3-2 class C
  • wide input voltage range, limited only by external components
  • doesn´t require an opto-isolator
  • exact regulated output LED current (+-5%)
  • protection against open LED and shortcut
  • possibility to control via multiple CTRL pins
  • thermally enhanced MSOP-16 package

Do not miss these articles

Do you like our articles? Do not miss any of them! You do not have to worry about anything, we will arrange delivery to you.

Additional products


S380 DIOTEC  
S380

Bridge Rectifier 0,8A/800V MiniDIL 2,54

Bridge Rectifiers

Ord. No.: 40607
Manufacturer: DIOTEC
in stock 8500 pcs
20 pcs+
40 pcs+
200 pcs+
1000 pcs+
5000 pcs+
0,0899 €
0,0818 €
0,0728 €
0,0667 €
0,0605 €
ORDER:
  • ADD TO CART
  • Get Quote
  • Add to favorites
  • Add to watchdog
  • Add item to compare

B380S-SLIM DIOTEC  
B380S-SLIM

Bridge Rectifier 1A/800V SO-DIL

Bridge Rectifiers

Ord. No.: 40932
Manufacturer: DIOTEC
in stock 2600 pcs
20 pcs+
40 pcs+
200 pcs+
1000 pcs+
5000 pcs+
0,0895 €
0,0762 €
0,0677 €
0,0621 €
0,0576 €
ORDER:
  • ADD TO CART
  • Get Quote
  • Add to favorites
  • Add to watchdog
  • Add item to compare

CAX-0,4-39 TALEMA  
CAX-0,4-39

Common Mode Choke 2x39mH 0,4A 1,769Ohm THT 20x17,8x12,8mm

Common Mode Chokes

Ord. No.: 73454
Manufacturer: TALEMA
in stock 0 pcs
(06/17/2022: 250 pcs)
1 pcs+
2 pcs+
10 pcs+
50 pcs+
200 pcs+
2,02 €
1,84 €
1,64 €
1,50 €
1,41 €
ORDER:
  • ADD TO CART
  • Get Quote
  • Add to favorites
  • Add to watchdog
  • Add item to compare

CAV-1,0-27 TALEMA  
CAV-1,0-27

Common Mode Choke 2x27mH 1A 537mOhm THT 30x27x18mm

Common Mode Chokes

Ord. No.: 74459
Manufacturer: TALEMA
in stock 125 pcs
1 pcs+
5 pcs+
20 pcs+
150 pcs+
2,88 €
2,56 €
2,37 €
2,11 €
ORDER:
  • ADD TO CART
  • Get Quote
  • Add to favorites
  • Add to watchdog
  • Add item to compare

R46 0,1uF 275V 10% (R46KI310000M1K1) KEMET  
R46 0,1uF 275V 10% (R46KI310000M1K1)

Film Capacitor 5x11x18 P15mm

EMI, RFI Suppression Film Capacitors

Ord. No.: 40846
Manufacturer: KEMET
in stock 100 pcs
(06/24/2022: 2000 pcs)
20 pcs+
40 pcs+
200 pcs+
1000 pcs+
5000 pcs+
0,0895 €
0,0788 €
0,0700 €
0,0642 €
0,0596 €
ORDER:
  • ADD TO CART
  • Get Quote
  • Add to favorites
  • Add to watchdog
  • Add item to compare

UF4007 DIOTEC  
UF4007

Fast Rectifier Diode 1A/1000V DO41

Rectifier diodes

Ord. No.: 4058
Manufacturer: DIOTEC
in stock 5500 pcs
50 pcs+
100 pcs+
500 pcs+
2000 pcs+
10000 pcs+
0,0432 €
0,0417 €
0,0372 €
0,0344 €
0,0312 €
ORDER:
  • ADD TO CART
  • Get Quote
  • Add to favorites
  • Add to watchdog
  • Add item to compare

STP6NK60Z STMICROELECTRONICS  
STP6NK60Z

Transistor MOSFET N-Ch. 6A/600V TO220

FET - Field Effect Transistors - Power

Ord. No.: 24156
Manufacturer: STMICROELECTRONICS
in stock 2 pcs
2 pcs+
4 pcs+
10 pcs+
50 pcs+
300 pcs+
1,44 €
1,40 €
1,28 €
1,18 €
1,06 €
ORDER:
  • ADD TO CART
  • Get Quote
  • Add to favorites
  • Add to watchdog
  • Add item to compare

RZ 470uF 50V 105°C (RZ1H477M12020BB200) SAMWHA  
RZ 470uF 50V 105°C (RZ1H477M12020BB200)

Aluminium Electrolytic Capacitor D12x20mm P5

Electrolytic Capacitors

Ord. No.: 70028
Manufacturer: SAMWHA
No longer available

640-100K VISHAY BC COMPONENTS  
640-100K

NTC Thermistor 100kOhm 4190K Bead THT

NTC Thermistors

Ord. No.: 26810
Manufacturer: VISHAY BC COMPONENTS
in stock 687 pcs
5 pcs+
10 pcs+
50 pcs+
200 pcs+
1200 pcs+
0,3980 €
0,3370 €
0,3000 €
0,2770 €
0,2500 €
ORDER:
  • ADD TO CART
  • Get Quote
  • Add to favorites
  • Add to watchdog
  • Add item to compare

LT3799EMSE#PBF ANALOG DEVICES  
LT3799EMSE#PBF

LED Driver Active PFC MSOP16

Switching Voltage Regulators

Ord. No.: 111698
Manufacturer: ANALOG DEVICES
ORDER:
  • ADD TO CART
  • Get Quote
  • Add to favorites
  • Add to watchdog
  • Add item to compare
Get Quote
Do you agree with cookies being stored?
Welcome to the SOS electronic website. Before you enter our online world, we would like to ask you to allow us to store cookies on your browser. Your consent will help us view the site without error, measure its performance, and track additional statistics. Apart from that, we can bring you an offer of our products and services, literally tailor-made. We also provide cookies to third parties. However, you are definitely safe with us.
The proper operation of the website
More stable technical control
Better marketing offer

More about cookies
More about personal data processing