Power Electronics
Why ready-made DC/DC converter modules are
often the most cost-effective solution
Is do-it-yourself
still an option?
Reinhard Zimmermann
Product Marketing Manager
RECOM Power GmbH
Electrical devices are normally powered through modular power supplies or
batteries. Normally, however, these solutions provide only one direct current voltage,
so that there is a need for DC/DC converters on the printed circuit board to power
the various components. The 5V power supplied by the source is, for instance,
converted on the spot to 3.3V for the processor, or to ±12V for the operational
amplifiers. DC/DC converters, however, perform a number of additional tasks, such
as isolating assemblies. This might be necessary for safety reasons, as is the case in
measuring probes used in medical applications. Sometimes, isolation is required for
purely technical reasons, for instance for the galvanic isolation of amplifier channels.
It therefore comes as no surprise that virtually all printed circuit boards are equipped
with numerous DC/DC converters.
Fig. 1: DC/DC converters not
only provide the printed circuit
board components with the
voltage they require, but also
act as insulators at interface
ports and amplifier channels to
prevent ground loops.
T
he circuitry of DC/DC
converters is not
exactly complex, and
the internet is full of design
proposals and ideas.
Companies are therefore often
tempted to ask their in-house
developers to build the
necessary DC/DC converters
themselves. In theory, this
should lead to considerable
cost savings. In practice,
things are not as simple, as
this article on the intricacies of
analog circuit technology
demonstrates.
Need for expert knowhow in analogue
technology
There are two main reasons
why device manufacturers
are hesitant to opt for "offthe-shelf" DC/DC
converters, which is
common practice for AC/DC
power supplies. On the one
hand, DC/DC converters
operate at much lower
input voltages, and
therefore appear more
manageable. On the other
ELE Times | 55 | November, 2016