Did =
you know you=20
can design a PCB coil for inductive sensing in five minutes with=20
WEBENCH=C2=AE?
If you =
are=20
considering using an inductance-to-digital =
converter, like the=20
LDC1000, but are concerned =
about the time=20
it takes to design a sensor coil, have a look at WEBENCH=C2=AE =
Inductive Sensing=20
Designer.
WEBENCH=20
Inductive Sensing Designer is an online tool that designs sensor coils =
for many=20
inductive sensing applications in just five minutes. The finished coil =
can then=20
be manufactured and connected to an inductive sensing evaluation board =
for=20
prototyping. After the prototype stage, the coil design can be copied to =
the=20
main PCB artwork.
To =
design a coil=20
in WEBENCH, you can follow a simple 3-step approach: input your system=20
requirements, select an auto-generated coil and export it to your =
preferred PCB=20
layout software.
1. Input=20
system requirements.
Suppose you want=20
to design the smallest possible coil on a 4-layer PCB that can measure a =
10cm=20
stainless steel target with 5=CE=BCm resolution at up to 2cm distance =
between the=20
target and the sensor coil. You can insert these requirements into the=20
=E2=80=98Requirements and Conceptual Diagram=E2=80=99 panel. You can =
even pre-filter the results=20
in the filter panel if you=E2=80=99d like.
Remember that=20
the maximum target distance at a given resolution varies with coil =
diameter. To=20
learn more about maximum target distance, check out this blog post: =
Top three LDC1000 =
questions.=20
2. =20
Review simulated performance of the auto-generated coils and select the =
best=20
match for your system.
After =
clicking=20
the 'Recalculate=E2=80=99 button, WEBENCH shows eight solutions that =
meet the system=20
requirements. The tool calculates many coil parameters automatically, =
including=20
number of turns per layer, coil inductance, and simulated resolution. It =
also=20
suggests a sensor capacitor value. You don=E2=80=99t have to use the =
suggested sensor=20
capacitor value, but the simulation curves on the =
=E2=80=98Charts=E2=80=99 screen shown below=20
are based on the suggested value
You =
can sort the=20
results by coil diameter and select the smallest 4-layer PCB. In this =
example,=20
WEBENCH shows that the smallest is =E2=80=98PCB inductor coil =
6=E2=80=99: a 3cm diameter coil=20
with 69 turns per layer and a free field inductance of =
830=CE=BCH.
After =
clicking=20
the 'Open Design' button of the chosen coil, you can review simulation =
plots (Rp=20
vs. distance, inductance vs. distance and resolution vs. distance) and =
operating=20
values. For convenience, WEBENCH also shows schematics, bill of =
materials and a=20
preview image of the coil.
If the =
chosen=20
coil does not suit your needs, you have the option of clicking on the =
=E2=80=98back=E2=80=99=20
button and selecting another coil.
3. =20
Export the coil to your favorite PCB layout =
software.
If you =
are happy=20
with the design, simply click on the 'CAD File Export' button. Five =
common PCB=20
CAD tools output formats are available:
I =
exported the=20
coil to Altium designer. This is what the PCB project looks like in=20
Altium:
WEBENCH is a=20
powerful online tool that generates inductive sensing coils in only five =
minutes. It greatly reduces prototyping and development time for most =
inductive=20
sensing systems.
Additional=20
resources: