Table of Contents
- RF Signal Integrity to Power Integrity
- about SEPIA
- about QSPICE
- about PyQSPICE
- about SEPIA@QSPICE
- Basic Operation
- Usage / Example
- Sub-Circuit Parameters
- Usage from PyQSPICE
For the technical details, please visit and review the SEPIA article, that is the 11th post, part-11 in the RF Signal Integrity to Power Integirity, a series article-on the Microwave Journal.
SEPIA: Stability Evaluation for Power Integrity Analysis
The [SEPIA] is a control loop stability analysis tool developed by Mr. Steve Sandler at Picotest.com.
The SEPIA extracts frequency-domain parameters of our target circuit/loop, directly from time-domain, transient (.TRAN) simulations.
The SEPIA method is based on a simple fact that every single circuit sharing the same qualify factor Q exhibits the mathematically "similar" ringing to decay shape by assuming it is a quadratic system.
Copyright © 2014 Picotest
The "SEPIA" compiled binary, the DLL (Windows Dynamic Link Library) file, available from this repository is a copyright intellectual property of Picotest.com. All rights reserved.
Please contact [email protected] for more information.
In this repository, by a courtesy of Mr. Steve Sandler, the SEPIA is implemented into the QSPICE.
The 
The PyQSPICE is a Python wrapper-module for the QSPICE, available from this Qorvo repository on GitHub. By using the QSPICE as a strong back-end simulator, it supports complex data processing and data plotting.
The QSPICE supports user-defined C++ and/or Verilog circuit blocks. The SEPIA processing routines are implemented as one of such user-defined circuit blocks, that is the DLL binary available here.
Important
This SEPIA@QSPICE module is a SUB-SET of the SEPIA, where NOT ALL the SEPIA PROCESUREs implemented.
At a high-level, the SEPIA@QSPICE circuit module operates in following steps.
- As a transient simulation goes, it detects ringing peaks and record them in its internal memory.
- At the end of the transient simulation, it extracts the control loop parameters based on the SEPIA routines.
2a. It extracts basic loop information: Q and frequency
2b. It model-fits and generates simplified RLC circuit model(s) representing the target loop, if options specified. - When specified by options, it further runs extra/follow-up simulations to RLC models.
The basic usage of the SEPIA@QSPICE and examples are summarized in this session file by utilizing the Jupyter Lab environment.
Important
So to run the Python code recorded in the session file, please install below 2 software packages.
The SEPIA@QSPICE module takes four (4) sub-circuit parameters and all parameters are explained in this manual.
When using SEPIA@QSPICE from a PyQSPICE environment, we can use a PyQSPICE method to control the SEPIA@QSPICE options described in this manual.