NL5 is the Non-Linear Electronic Circuit Simulator. The first version of
NL for personal computers was developed in the early ‘90s as a tool for
switching power supplies design. Since then NL has evolved into the
Microsoft Windows®-based NL4, which has been used extensively by
world-class engineers in different fields of electronics for almost 10
years. NL5 is the first version to be publicly available.
How does NL5 work?
Unlike conventional SPICE-based simulators, which pretend to perform
accurate simulation of electronic circuits using complex and detailed
non-linear component models with dozens of parameters, the NL5 approach
is quite different.
First, NL5 deals with ideal components as much as possible. An ideal
component is one that provides just a basic functionality required for
component of that type. As a rule, it is very simple and described by a
minimal number of parameters. As a result, its behavior is clear and
predictable. For example, an ideal switch has zero resistance when
closed, infinite resistance when open, and it is switching instantly.
For such a switch no parameters are required at all.
Second, non-linear components (e.g. diodes, transistors, or amplifiers)
are represented as piecewise linear (PWL): consisting of a number of
linear segments. For instance, a simple diode is either open or closed,
so that its PWL representation consists of just two segments. As long as
all of the components are staying within their current linear segment,
the same system of linear equations can be used. The system is modified
only at the moments when at least one component changes its linear
segment. This can always be done much faster than solving complex
non-linear equations at almost every step of simulation, which is what
SPICE-based simulators usually do.
Understanding these NL5 principles gives users full control of the
simulation process. Using ideal components with simple PWL models
results in an extremely fast simulation, and gives a general idea of
circuit functionality very quickly. On the other hand, more accurate
results can be obtained by identifying critical components (those that
affect circuit performance the most), and using more complex models for
those components. Thus, users can always make a reasonable trade-off
between simulation speed and desired level of accuracy.
Why use NL5?
NL5’s major advantage is its ability to do iterations of the schematic
and perform a simulation extremely fast. This is especially important in
early stages of a project, when, using ideal components and simple
models, engineers can evaluate a general concept and prove the
feasibility of the design very quickly. After that, a thorough analysis
can be performed by applying more accurate models and adding reasonable
complexity to critical components.
Despite being originally designed for simulating switching power
supplies, NL5 has proved to be an excellent simulation tool for almost
any type of electronic circuitry, from nanoseconds transmission lines
and high power RF generators, to precision instrumentation and digital
signal processing. Recently added frequency domain analysis and some
quite unique features broaden NL5’s horizons, offering engineers almost
all they would ever need for productive work.
Who can use NL5?
NL5 perfectly fits the needs of all users, regardless of their experience, interests, and expectations.
NL5 is ideal for novices and students studying electronics. The learning
curve is negligibly short: basic knowledge of the Windows® operating
system is all that’s needed to start working with NL5. A friendly and
intuitive interface allows fast modifying of the schematic, even
“on-the-fly” editing while the simulation is running, thus giving
instant answers to “what if …?” questions.
Experienced engineers can simulate rather large systems, taking
advantage of extremely fast and robust algorithm, since the convergence
problem inherent to SPICE is no longer an issue. A simple, yet powerful,
scripting language allows the user to perform complex tasks running NL5
as “add-on” simulation engine with popular engineering tools such as
MATLAB® and others.
Due to the very basic nature of ideal components used in NL5, its
application area is not limited to electronics. It can be successfully
used for systems simulation by researchers in many disciplines, such as
mechanics, thermodynamics, fluid dynamics, to name a few.