Linear LT3748 Demo Manual

Description
Demonstration circuit 1860B is an isolated flyback con-
verter featuring the LT3748. 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
perForMAnce sUMMArY
PARAMETER
Input Voltage Range
Output Voltage
Maximum Output Current
Minimum Output Current
Output Voltage Ripple (Peak to Peak)
Efficiency
DEMO MANUAL DC1860B
No-Opto Isolated FlybacK
Converter for PSE Applications
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
http://www.linear.com/demo
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.
(T = 25°C)
A
CONDITIONS
V = 10V – 15V
IN
I = 0V – 700 mA
OUT
V = 10V – 15V
IN
V = 10V – 15V
IN
V = 10V – 15V, I = 0 – 700mA
IN OUT
V = 13.2V, I = 700mA
IN OUT
LT3748
MIN TYP MAX UNITS
10 12 15
50 52.5 55
700
0
150
87.8
dc1860bfa
V
V
mA
mA
mV
%
1