1
dc1816bfc
DEMO MANUAL DC1816B
Description
LT3799-1
Offline Isolated Flyback LED
Driver with PFC
Demonstration circuit 1816B is an off-line isolated flyback
LED driver featuring LT
®
3799-1. The demo board provides
a single constant current output of 3A over an LED string
voltage from 22V to 38V. It is optimized to operate over
a wide AC input voltage range (90VAC to 305VAC, 47Hz
to 63Hz). LED current typically stays within ±5% over the
whole input voltage range. It provides a high power factor
(>0.9) enabling a single design to be used worldwide. It
is also designed to comply with the IEC 61000-3-2 Class
C harmonics standard and the EN55015B conducted EMI
standard.
The LT3799-1 controls an isolated flyback converter in
boundary mode. Its novel current sensing scheme deliv-
ers a well-regulated output current to the secondary side
L
, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
performance summary
without using an opto-coupler. Open- and shorted-LED
protection ensures long term reliability.
The LT3799-1 is available in a low profile, thermally-
enhanced 16-lead MSOP package.
The LT3799-1 data sheet gives a complete description
of the device, operation and application information. The
data sheet must be read in conjunction with this quick
start guide for demo circuit 1816B.
Design files for this circuit board are available at
http://www.linear.com/demo
(T
A
= 25°C)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Voltage Range
Line Frequency, 47Hz to 63Hz
90
277
305
VAC
Output Current I
OUT
V
IN
= 120VAC, V
LED
= 36V
3
A
Output Voltage
22
36
38
V
Open LED Voltage
(Note 1)
45
V
Note 1: For applications with low LED string voltage, FB pin divider resistor R4 and output clamp Z3 can be adjusted to reduce the open voltage limit.
See “Protection from Open LED and Shorted LED Faults” section in the data sheet for detail.
