1
dc1860bfa
DEMO MANUAL DC1860B
Description
LT3748
No-Opto Isolated FlybacK
Converter for PSE Applications
Demonstration circuit 1860B is an isolated flyback con-
. This demo circuit is designed
for Power Sourcing Equipment (PSE) applications with a
52.5V output from a 10V to 15V DC input, with nominal
input voltage of 12V. The output current is from 0mA to
700mA, and is capable of a maximum short period overload
current of 900mA. Table 1 summarizes the performance
of the demo board. This demo circuit can also be easily
modified for different PSE applications with some pre-
designed transformers.
The LT3748 is a high input voltage isolated flyback control-
ler operating with input supply voltages from 5V to 100V,
and 1.9A average gate drive source and sink current. The
LT3748 utilizes boundary mode operation to provide a high
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
efficiency, small size solution with improved regulation.
The part senses the isolated output voltage directly from
the primary side flyback waveform during the off time of
the power switch. No third winding, opto-coupler, or signal
transformer is required for regulation.
The LT3748 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for demo circuit 1860B.
Design files for this circuit board are available at
(T
A
= 25°C)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Voltage Range
10
12
15
V
Output Voltage
V
IN
= 10V – 15V
I
OUT
= 0V – 700 mA
50
52.5
55
V
Maximum Output Current
V
IN
= 10V – 15V
700
mA
Minimum Output Current
V
IN
= 10V – 15V
0
mA
Output Voltage Ripple (Peak to Peak)
V
IN
= 10V – 15V, I
OUT
= 0 – 700mA
150
mV
Efficiency
V
IN
= 13.2V, I
OUT
= 700mA
87.8
%
