DC Power Supply
DC Power
Supply is the term used to describe an electronic
power conversion unit which converts AC Mains electricity
into DC power. A DC Power Supply is normally defined
by the voltage level and current which it is capable
of producing, so in real terms a 120W dc power supply
could be defined as a 24Vdc power supply rated at 5A
or a 12Vdc power supply rated at 10A.
DC Power Supplies are used in a large number of applications
such as computers, telecommunications equipment, radios,
control systems, LED lighting, and in fact most electronic
devices are powered using a dc power supply whether
this is built into the actual electronic device itself
or whether it is an external dc power supply feeding
the power to the device.
 Traditionally
a DC power supply would use a large transformer which
was costly, bulky and heavy but over the last twenty
years these linear regulated power supplies have been
gradually replaced by smaller, more efficient switched
mode technology which is lighter, takes up less space
and generally costs less. Switched mode power supplies
(SMPS) are fine I the majority of applications but their
switching circuits can provide noise to sensitive devices
and as such there is still a need (albeit small) for
quiet, stable linear power supply technology.
A DC power supply comes in many different formats.
Often referred to as an AC/DC power supply, AC/DC Converter,
rectifier, or adaptor a dc power supply can be as simple
as an open frame pcb, or fully enclosed with a lead
in and lead out as in the case of a laptop charger.
Control and automation systems often require a din rail
mounted dc power supply and most commonly these are
24Vdc output power supply units. In higher level and
more critical applications a dc power supply system
is often configured with individual power supplies mounted
in racks and connected together in either a parallel
or n+1 configuration so that in the event of a module
failure there is another unit available to take of the
supply of dc power and the defective unit can be swiftly
exchanged for a fully working unit.
Another distinct advantage of equipment being powered
by a low voltage dc power supply is the safety consideration.
Historically equipment may have worked only on AC mains
which if not properly handled can be dangerous, so if
devices and equipment can be run from low voltage dc
such as 5Vdc, 12dc, or 24Vdc then the safety implications
are far less onerus
Where battery backup is required dc power supply technology
is often used for battery charging. In its simplest
form a dc power supply with an accurate current limit
can be used as a float charger, or if better charging
characteristics are required then dc power supply technology
is closely controlled to provide 3 or 4 stage charging
circuits.
For more information please click the AC/DC Power Supplies
link on the left of this page where you can view the
products by mounting style (din rail mount, chassis
mount, open frame and 19” rack mount) or select
by voltage range and power required and the site will
provide a selection of suitable units.
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