Evaluation Engineering - 24

AUTOMATED TEST

HOW TO CHOOSE AN
ELECTRONIC LOAD

What things do we need to consider before purchasing an electronic load?
We discuss what electronic loads are, what points to consider before
purchasing, and why reading the specifications just isn't good enough.
By Tomoaki Mori, Kikusui America
It is a well-known fact that electronic loads are essential in power
supply and battery testing applications.
However, it can be hard to decide which
electronic load is best for an application
because of the variety of options in the
market today. In this article we explore
the key characteristics of electronic
loads and what to consider when starting
a new application.
When it comes to electronic loads,
there are two primary types of power
consumption: linear regulator, and regenerative. Linear-regulator types are used
in applications that require fast response
and low-level noise. Regenerative types
feature high power-density and low power
losses. In linear regulator types, power
is consumed by devices which convert
electrical energy to heat. In regenerative
types, switching power devices are used
to return power to the AC line.
E le c t r on ic lo a d s h av e m a ny
functions,such as low-voltage operation,
combined operating modes, remote-control interfaces, time-dependent settings,
measurement functions and more. There
are too many to list here, but it is important to consider which functions will be
useful for an application (see Figure 1).
The operating range of electronic loads
is often given in terms of power, current
and voltage. If our application requires a
larger capacity than an electronic load

EVALUATION ENGINEERING SEPTEMBER 2020

offers, it will not be worth considering.
However, if an electronic load has a capacity that is much larger than our application, it may be a waste of resources.
In addition to the unnecessary cost and
size of an electronic load, a larger capacity may mean poorer performance. It is
often the case that the higher the rating,
the worse the setting accuracy, setting
resolution and response is for lower range
applications.
Figure 1: An example of the functions
electronic loads have is this Arbitrary I-V
characteristic profile, which allows users to define
an I-V profile to emulate non-linear loads, such as
LED's, or PV's.

Figure 2: A diagram to illustrate the boundaries
of theoretical load A.

A Tale of Two Loads
Let's use an example of load A and B,
which have similar but different operating

Figure 3: A diagram to illustrate the boundaries
of theoretical load B.

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