Ansys Lumerical CHARGE

Transient Analysis

• A user-specified time interval is used to compute the transient output variables in Lumerical CHARGE transient analysis section. A DC analysis can automatically determine the beginning conditions. All sources (such as power supply) that are not time-dependent are set to their DC value.
• Initial conditions are assumed at the start of the analysis rather than the outcome of the DC operating point analysis if Josephson junctions are present or if the UIC option is specified. All sources should start with zero output in Josephson junctions. The transient simulation can be run at each point over a variety of bias settings by combining transient analysis with a DC sweep.

Transfer Function Analysis

• The AC small signal transfer function, input impedance, and output impedance of a network are calculated by Lumerical HEAT’s transfer analysis section. The DC operating point for AC analysis is automatically calculated using an operating point analysis.
• Moreover, the transfer function can be estimated at each point over a variety of bias circumstances by combining the transfer analysis with a DC sweep.

Pole-Zero Analysis

• The poles and/or zeros in the small-signal AC transfer function are computed by the pole-zero analysis section of Lumerical CHARGE. All of the nonlinear components in the circuit’s linearized, small-signal models are then determined after the DC operating point has been calculated. The poles and zeros are then determined using this circuit. The transfer functions (output voltage)/(input voltage) and/or (output voltage)/(input current) are readily accessible for engineers to employ.
• The poles and zeros of functions like input/output impedance and voltage gain can be found using these two forms of transfer functions, which cover all circumstances. With resistors, capacitors, inductors, linear-controlled sources, independent sources, BJTs, MOSFETs, JFETs, and diodes, the pole-zero analysis can be applied.

Small Signal AC Simulation

• The AC output variables are calculated as a function of frequency by the AC small-signal section of Lumerical HEAT. The program initially calculates the circuit’s DC operating point before determining linearized, small-signal models for each of the circuit’s nonlinear components. The resulting linear circuit is next examined across a user-specified frequency range.
• Typically, a transfer function is the desired result of an AC small-signal analysis (voltage gain, transimpedance, etc). If there is just one AC input in the circuit, it is practical to set it to unity and zero phase such that the output variables have the same value as their transfer function to the input.  A DC sweep and AC analysis can then be used in tandem to perform an alternating current analysis at each position under various bias conditions.