# Bias Point Analysis

The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform

### Dennis Fitzpatrick – 1st expert on this subject based on the ideXlab platform

• ##### Convergence Problems and Error Messages
Analog Design and Simulation using OrCAD Capture and PSpice, 2020
Co-Authors: Dennis Fitzpatrick

Abstract:

PSpice uses the Newton–Raphson iteration method to calculate the nodal voltages and currents for nonlinear circuit equations. If a solution cannot be found, PSpice reports that the simulation has failed owing to a convergence problem. Simulations can also fail because of circuit errors and missing or incorrect parameters specified. Some of these common errors are discussed in this chapter. The Bias Point Analysis is the starting Point for a transient Analysis and a DC sweep. If there is a convergence issue then the simulation pauses and the PSpice Runtime Settings window appears. Users can then change a simulation parameter and resume the simulation. There are no clearly defined rules for solving convergence problems. What users need to do is to try to localize the problem. For large circuits, one methodically needs to remove and simulate smaller portions of the circuit. A hierarchical design, made up of blocks of circuitry, can help in solving convergence problems. Another approach for large circuits is to replace parts of circuits with Analog Behavioral Models, which use mathematical expressions or tables to model components or circuit behavior. The simulation settings can be accessed via the simulation profile and selecting the Options tab.

• ##### Chapter 7 – Transient Analysis
Analog Design and Simulation using OrCAD Capture and PSpice, 2020
Co-Authors: Dennis Fitzpatrick

Abstract:

Publisher Summary
Transient Analysis calculates a circuit’s response over a period of time defined by the user. The accuracy of the transient Analysis is dependent on the size of internal time steps, which together make up the complete simulation time known as the Run to time or Stop time. For every time step, the node voltages and currents are calculated and compared to the previous time step DC solution. Only when the difference between two DC solutions falls within a specified tolerance (accuracy) will the Analysis move on to the next internal time step. The time step is dynamically adjusted until a solution within tolerance is found.

The value for the maximum internal time step can be defined by the user. There are some circuits, where a DC solution cannot be found, as in the case of oscillators. For these circuits, there is an option in the simulation profile to skip over the initial DC Bias Point Analysis. Scheduling allows users to dynamically alter a simulation setting for a transient Analysis; for example, users may want to use a smaller step size during periods that require greater accuracy and relax the accuracy for periods of less activity. Check Points were introduced in version 16.2 to allow users to effectively mark and save the state of a transient simulation at a check Point and to restart transient simulations from defined check Points. Input waveforms can also be defined using pairs of time–voltage coordinates, which can be entered in the Property Editor, or read from an external text file.

• ##### Chapter 4 – AC Analysis
Analog Design and Simulation using OrCAD Capture and PSpice, 2012
Co-Authors: Dennis Fitzpatrick

Abstract:

Publisher Summary
The AC Analysis is used to calculate the frequency and phase response of a circuit by frequency sweeping an AC source connected to the circuit. The AC sweep Analysis is a linear Analysis and calculates what is known as the small signal response of a circuit over a range of frequencies by replacing any nonlinear circuit device models with linear models. The DC Bias Point Analysis is run prior to the AC Analysis, and is used to effectively linearize the circuit around the DC Bias Point. The AC Analysis does not take into account effects such as clipping. Users will have to run a transient Analysis to determine these effects. To perform an AC Analysis, the independent voltage source VAC or current source IAC from the source library is used. Any independent voltage source which has an AC property attached to the part can be used as an input to the circuit. By default, the magnitude of the VAC source is 1 V. In calculating the frequency response of a circuit, users are normally looking to calculate the gain and phase response of the circuit. One example in which an AC Analysis is used to determine the frequency response of a circuit is the notch filter, which attenuates a narrow band of unwanted frequencies. To set up an AC Analysis, a PSpice simulation profile needs to be created. AC markers can be used to display dB magnitude, phase, group delay, and the real and imaginary parts of voltage and current.

### N.n. Idris – 2nd expert on this subject based on the ideXlab platform

• ##### Design of Power Stage and Controller for DC-DC Converter Systems Using PSPICE
2005 International Conference on Power Electronics and Drives Systems, 2005
Co-Authors: N.d. Muhamad, A.h.m. Yatim, N.n. Idris

Abstract:

A complete set of SPICE-compatible design equations for design buck converter system is developed in this paper. In this approach, the power stage and controller design equations are programmed in PSPICE. For this purpose, an option available in PSPICE called analog behavioral modeling (ABM) is used. In this manner, the parameter of power stage and the component values of the error amplifier can be easily obtained by means of PSPICE Bias Point Analysis. The obtained parameters can be passed to other circuit models to perform frequency response and transient Analysis. The methodology of development is presented in details. A design example is included to demonstrate the effectiveness of the proposed approach in designing DC-DC converter systems

### N.d. Muhamad – 3rd expert on this subject based on the ideXlab platform

• ##### Design of Power Stage and Controller for DC-DC Converter Systems Using PSPICE
2005 International Conference on Power Electronics and Drives Systems, 2005
Co-Authors: N.d. Muhamad, A.h.m. Yatim, N.n. Idris

Abstract:

A complete set of SPICE-compatible design equations for design buck converter system is developed in this paper. In this approach, the power stage and controller design equations are programmed in PSPICE. For this purpose, an option available in PSPICE called analog behavioral modeling (ABM) is used. In this manner, the parameter of power stage and the component values of the error amplifier can be easily obtained by means of PSPICE Bias Point Analysis. The obtained parameters can be passed to other circuit models to perform frequency response and transient Analysis. The methodology of development is presented in details. A design example is included to demonstrate the effectiveness of the proposed approach in designing DC-DC converter systems