DC to DC Converter: An Overview

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DC to DC Converter An Overview
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DC-DC switching converters are widely used in
most of the portable devices. They are efficient
in generating various regulated supply voltages
for different sub-blocks within the same system
board. Typical system board for any portable
device can easily have various switching
converters.
DC to DC converter comes in non-isolated and
isolated varieties. Isolation is typically
determined by whether the input ground is
connected to the output ground or not. Four
common topologies are Buck Boost Buck-boost SEPIC
converters
Important performance characteristics DC to DC
converter datasheets has certain parameters that
describe their important features. Here are some
of the important features
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EFFICIENCY Efficiency is that fraction of
input power which reaches the load. Some of the
DC to DC converters are 90 efficient. When you
are using a DC-DC converter, it is better to
ensure that the source providing power to the
converter is providing enough power to account
for the inefficiency. The thumb rule is to assume
that a DC-DC converter is 80 efficient, and then
use a source with 125 the load power. The
efficiency of a DC-DC converter is typically
specified in curves, with its peak efficiency
achieved at a certain load current. Efficiency
might be lower at lower power outputs, where the
amount of power needed to power the circuit can
be compared to the load power.
CURRENT RATING This is the maximum amount of
current that a DC to DC converter can provide to
the load, and the user should try to have this.
However, the DC-DC converter can provide more
than this amount of current, but it will get hot
and might fail. TEMPERATURE RATING This is the
maximum amount of ambient temperature that a
DC-DC converter should run under the full load.
If it is pushed past this safety limit, the
converter may start overheating and get damaged,
or may even shut down as a protective measure.
TRANSIENT RESPONSE DC to DC converters uses
closed feedback loops for providing a regulated
output. Changes in load current or input voltage
may lead to temporary shifts. Speed of control
loop response will give you the idea of how long
it will take for the buck converter to respond to
the changing conditions and get the output
voltage in regulation. SIZE AND WEIGHT A DC to
DC converter can operate at very high
frequencies, allowing them to be made small. This
is because some loss mechanisms increase with the
frequency, causing them to be less efficient
this is somewhat a trade-off between size and
efficiency.