LT4180_15 Datasheet, PDF (1/18 Pages) Linear Technology – Virtual Remote Sense Controller

LT4180
Virtual Remote Sense
Controller
Features
n _{Tight Load Regulation with Highly Resistive Cables}
without Requiring Remote Sense Wiring
n _{Compatible with Isolated and Nonisolated Power}
Supplies
n _{±1% Internal Voltage Reference}
n _{5mA Sink Current Capability}
n _{Soft-Correct Reduces Turn-On Transients}
n _{Undervoltage and Overvoltage Protection}
n _{Pin-Programmable Dither Frequency}
n _{Optional Spread Spectrum Dither}
n _{Wide VIN Range: 3.1V to 50V}
n _{24-Lead SSOP Package}
Applications
n _{12V High Intensity Lamps}
n _{28V Industrial Systems}
n _{High Power (>40 Watts) CAT5 Cable Systems}
n _{Wiring Drop Cancellation for Notebook Computer}
Battery Charging
n _{AC and DC Adaptors}
n _{Well-Logging and Other Remote Instrumentation}
n _{Surveillance Equipment}
Description
The LT^®4180 solves the problem of providing tight load
regulation over long, highly resistive cables without
requiring an additional pair of remote sense wires. This
Virtual Remote Sense™ device continuously interrogates
the line impedance and corrects the power supply output
voltage via its feedback loop to maintain a steady voltage
at the load regardless of current changes.
The LT4180 is a full-featured controller with 5mA opto-
isolator sink capability, under/overvoltage lockout,
soft-start and a ±1% internal voltage reference. The
Virtual Remote Sense feature set includes user-program-
mable dither frequency and optional spread spectrum
dither.
The LT4180 works with any topology and type of isolated
or nonisolated power supply, including DC/DC converters
and adjustable linear regulators.
The LT4180 is available in a 24-lead, SSOP package.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Virtual Remote Sense is a trademark of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
Typical Application
Isolated Power Supply with Virtual Remote Sense
+
SWITCHING
REGULATOR
V_C
–
CAT5E CABLE
R_SENSE
LINE
LINE
C_L R_L
V_IN SENSE DIV0 DIV1 DIV2 SPREAD CHOLD1 CHOLD2 CHOLD3 CHOLD4
DRAIN
COMP
LT4180
VIRTUAL REMOTE SENSE
RUN FB
OV
R_OSC
C_OSC
4180 TA01a
For more information www.linear.com/4180
V_LOAD vs V_WIRE
5.00
4.99
4.98
4.97
4.96
4.95
4.94
4.93
4.92
4.91
0 0.5 1 1.5 2 2.5 3
V_WIRING (V)
4180 TAO1b
4180fb
1