Topological Conflicts

This section describes topological conflicts

Topological conflicts in the circuit are: state degenerations and source degenerations. These conflicts are hard to analyze and to simulate. In most cases, as a result of circuit analysis an infinite current/voltage can occur.

State degenerations are degenerated capacitances and inductances in the circuit. A capacitor connected in parallel with a voltage source is degenerated in Figure 1. An inductor connected in series with a current source is degenerated in Figure 1. Degenerated capacitors and inductors are ignored. A circuit with degenerated state variables behaves exactly in the same way as without them.

Figure 1: State degenerations

Figure 2: Warning report of degenerated capacitance and inductance

There are two types of source degenerations. Direct degeneration of independent sources and direct degenerations of independent sources with zero sources. Zero sources are open and closed switches. An open switch is a current source with zero current, while a closed switch is a voltage source with zero voltage.

Direct degenerations of an independent voltage source cannot be resolved. Compilation of such a circuits will fail and an error report will be printed out.

Figure 3: Direct degeneration of independent sources

Figure 4: Error massages in case of independent source degenerations

Degenerations of independent sources with zero sources (open and closed switches), shown in Figure 5, will be automatically solved as following: a closed switch connected in parallel with a voltage source will be treated as an open switch, while an open switch connected in series with an independent current source will be treated as a closed switch. In other words, closing a switch that is connected in parallel with an independent voltage source has no effect, and opening a switch connected in series with an independent current source has no effect on the circuit. In case of these types of degeneration a warning message will be generated during compilation.

Figure 5: Direct degeneration of independent sources and zero sources

Figure 6: Warning report of degenerated closed and opened switch

Sometimes this type of the degenerations can occur in regular circuits when a coupling component is inserted. In these cases, a correct snubber or shunt circuits have to be used.