QuickField PCB 2.5D Current Flow Solver

PCB 2.5D Current Flow Solver 1.0 is a lightweight utility that interacts with QuickField installed on the same computer and calculates DC current redistribution in multilayer PCB structures.

Each PCB layer is represented by a separate 2D QuickField DC Conduction region. Physical vias are treated as ideal equipotential interlayer connections. The utility automatically finds the common potential of every via from the current-balance condition and repeatedly solves the QuickField model until the specified global current residual is reached.

The source code, precompiled executable, and full PDF documentation are available in the download section.

Program launch options

The utility can be started with or without a command-line parameter:

PCB_25D.exe [/h] [filepath]

• /h – displays command-line help.
• filepath – path to the JSON via-connections file.

If PCB_25D.exe is launched without parameters, it opens a file-selection dialog.

Before starting the utility, open the target QuickField DC Conduction problem. Exactly one DC Conduction problem must be open.

Detailed processing information is appended to pcb2p5d_currentflow.log.

Preparing the QuickField model

Represent every PCB copper layer as a separate electrically disconnected 2D region in the same QuickField problem. Fixed-voltage terminals are defined directly in QuickField and are not included in the JSON list of unknown vias.

Every layer occurrence of a physical via must have an edge label and a block label with the same name. The edge label receives the calculated potential. The block label is placed inside a finite low-conductivity via-hole region and is used to select the boundary contour for current integration.

For example, a four-layer physical via may be represented by labels 1.3, 2.3, 3.3, and 4.3. All four labels are grouped together in the JSON file.

JSON configuration file

{
  "Vmin": 0.0,
  "Vmax": 0.02,
  "tolerance": 0.001,
  "max_iterations": 10,
  "vias": [
    {"name": "Via_1", "labels": ["1.1", "2.1", "3.1", "4.1"]},
    {"name": "Via_2", "labels": ["1.2", "2.2", "3.2", "4.2"]}
  ]
}

Calculation

For each trial set of via potentials, QuickField calculates the DC current field. The utility integrates the current at every layer occurrence of each via and forms the current-balance residuals.

Because the DC conduction problem is linear for fixed geometry and material properties, a coupling matrix is built by small perturbations of the via potentials. All via potentials are then corrected simultaneously by solving the matrix current-balance equations. The same matrix is reused until the specified global residual is reached or the iteration limit is exceeded.

The final potentials remain assigned to the QuickField via edge labels, and the final field solution remains available for inspection. The utility does not automatically save a new QuickField problem or data file.

Limitations

Interlayer connections are ideal equipotential nodes. Via-barrel resistance and inductance are not included. The utility is intended for resistive DC current redistribution between 2D PCB copper layers and is not a full 3D PCB or circuit solver.

Example:
2.5D Current Distribution in a Multilayer PCB

The software is provided "as is" and the author disclaims all warranties with regard to this software, including all implied warranties of merchantability and fitness. In no event shall the author be liable for any special, direct, indirect, or consequential damages, or any damages whatsoever resulting from loss of use, data, or profits, whether in an action of contract, negligence, or other tortious action, arising out of or in connection with the use or performance of this software.

• Accept terms above and download:
  Source code and precompiled executable
• Full documentation (PDF)