Alastair Barber

Creating PWL Files For LTSpice for PWM Signals

Composition of LTSpice circuit, real circuit and scope trace

Here is a very simple tool that can be used to simulate producing sine waves from PWM pulses and an appropriate filter in LTSpice. It can be downloaded and built or run onlineā€¦

The source code is in C++ and available on github. The same code can be run here in a webpage (read more about how that can be achieved - and should run here:

For example, if we were to use this to try and simulate PWM outut of a teensy 4.1 with the following parameters:

It would produce a file that could be read into LTSpice, which, in the following basic circuit LTSpice Circuit

when run would produce the following waveforms LTSpice waveform

When implemented in a real ciruit: Real Teensy-Op-Amp Circuit

the waveform on a scope is thus: Real waveform