PD-97816
HTM27092S
165°C, 270V Input, 92W, 92V Single Output
HIGH RELIABILITY
DC-DC CONVERTER
Description
The HTM27092S is a single output 92W DC-DC converter
designed to operate in extremely high temperature environments
such as those encountered in oil exploration. Features include
small size, low weight and high tolerance to environmental
stresses such as wide wide temperature extremes, severe
shock and vibration. All internal components and assembly
processes have been selected and developed to ensure reliable
performance in the intended operating environments.
HTM
Features
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190 to 400V DC Input Range
Up to 92W Output Power
92V, 1.0A Rated Output Voltage and Current
Internal EMI Filter
Magnetically Coupled Feedback
80% Minimum Efficiency
-20°Cto+165°C continuouswithtransientupto+175°C
100MΩ @ 500V DC Isolation
Under-Voltage Lockout
Short Circuit and Overload Protection
Output Over Voltage Limiter
Adjustable Output Voltage within 10% of nominal
External Inhibit
The converter incorporates a fixed frequency forward topology
with magnetic feedback and internal EMI filter. It also includes
an external inhibit port and have an adjustable output voltage.
It is enclosed in a hermetic 4.5" x 2.15" x 0.40" (4.0"x1.5"x0.40"H
excluding mounting tabs and I/O pins) AlSi package and weighs
less than 80 grams. The package utilizes rugged ceramic
feed-thru, copper-cored pins and is sealed using laser welding.
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Full environmental screening includes temperature cycling,
constant acceleration, fine and gross leak, and burn-in. Please
refer to Device Screening table. Variations in electrical
specifications and screening to meet custom requirements
can be accommodated
Low Weight < 80 grams
Circuit Description
Applications
n Down Hole Exploration Tools
The HTM27092S converter utilizes an enhanced forward
topology with two power switches and resonant reset. The
nominal switching frequency is 520 kHz. Electrical isolation
and tight output regulation are achieved through the use of a
magnetically coupled feedback. Voltage feed-forward with
duty factor limiting provides high line rejection and protection
against output over voltage due to certain component failures
in the internal control loop. This mechanism limits the maximum
output voltage to approximately 20% over the nominal
regardless of the line voltage with an output load that is
≥ 25% of the full rated output power.
The current limit point exhibits a slightly negative
temperature coefficient to reduce the possibility of
thermal runaway.
An external Inhibit port An external inhibit port (Pin 4) is
provided to control converter operation.The converter’s
operation is inhibited when this pin is pulled low. It is
designed to be driven by an open collector logic device.
The pin may be left open for normal operation and has
a nominal open circuit voltage of 4V with respect to the
input return (Pin 2).
Output current is limited under load fault conditions to
approximately 125% of the rating. An overload condition
causes the converter output to behave like a constant current
source with the output voltage dropping below nominal. The
converter will resume normal operation when the load current
is reduced below the current limit point. This protects the
converter from both overload and short circuit conditions.
The output voltage of all models can be adjusted using
a single external resistor within ±10% of nominal output
voltage.
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10/15/13