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dc1823bfb
DEMO MANUAL DC1823B
Description
LT4320
Ideal Diode Bridge Controller
Demonstration circuit 1823B features the ideal diode
bridge controller LT
®
4320 suitable for applications that
require high current AC to DC full-wave rectification or
DC polarity correction (see Table 2).
The LT4320 drives four N-channel MOSFETs to perform
full-wave rectification functionally similar to a diode bridge
but with much lower power dissipation. This topology eases
thermal design, and increases usable output voltage. In
addition, an all N-channel topology has benefits over a
P-channel topology
such as
a wider selection of MOSFETs,
lower cost, lower R
DS(ON)
, and smaller footprint.
Only a few essential components are required to oper-
ate the
LT4320 as an ideal diode bridge: four N-channel
MOSFETs, a bypass
ceramic capacitor, and
an AC
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
smoothing capacitor (C
LOAD
). The DC1823B includes four
very low R
DS(ON)
N-channel MOSFETs (2.5mΩ typical) to
support high current applications. When an AC voltage
source is used, the onboard C
LOAD
(C2) capacitor allows
for up to 1.5A of average output current. Add additional
C
LOAD
capacitance to support higher current AC applica-
tions. A unidirectional TVS (D1)
is included to protect the
application from brief overvoltage events up to the part
rating. A footprint for bidirectional TVS (D3) is also included
and is recommended for electrically harsh conditions.
Design files for this circuit board are available at
http://www.
linear.com/demo/DC1823B
Table 1. DC Efficiency of the DC1823B at Various Load Currents
DC INPUT VOLTAGE (V) DC OUTPUT VOLTAGE (V) DC LOAD CURRENT (A) EFFICIENCY (%) (TYPICAL)
20.004 19.966 10.008 99.81
20.005 19.906 20.013 99.51
20.006 19.825 30.012 99.10
