Although a diode is a sufficent and appropriate device for the switch a MOSFET would also work in this position,as shown in Fig. 1-13 When is on and is off,cur-rent flows upward out of the advantage of using a MOSFET is that it has a much lower voltage drop across it when conducting compared to a diode,resulting in lower power loss and a higher circuit efficiency. The disadvantage is that a more complexcontrol circuit is required to turm no when is turned off. However,several control cir-cuits are available to do this this control scheme is known as synchronous rectification or synchronous switching
In a power electronics application, the current source source in this circuit could represent an inductor that has a nearly constant current in it.
1.6 SPICE,PSPICE,AND CAPTURE
Computer simulation is a valuable analysis and desing tool that is emphasized throughout this text. SPICE is a circuit simulation program developed in the Department of Electrical Engineering and Computer Science at the University of California at Berkeley. PSpice is a commercially available adaptation of SPICE that was developed for the personal computer. Capture is a graphical interface
Program that enables a simulation to be done from a graphical representation of a circuit diagram Cadence provides a product called OrCAD Capture, and a demonstration version at no cost. Nearly all simulations described in text-book can be run using the demonstration version.
Simulation can take on various levels of device and component modeling, depending on the objective of the simulation. Most of the simulation examples and exercises use idealized or default component models, making the results first-order approximations, much the same as the analytical work done in the first discussion of a subject in any textbook. After understanding the fundamental op-eration of a power electronics circuit, the engineer can include detailed device models to predict more accurately the behavior of an actual circuit.
Probe, the graphics postprocessor program that accompanies PSpice, is especially useful.in Probe, the waveform of any current or voltage in a circuit can be shown graphically. This gives the student a look at circuit behavior that is not possible with pencil-and-paper analysis. Moreover, Probe is capable of mathematical computations involving currents and/or voltages, including numerical determination of rms and average values. Examples of PSpice analysis and design for power electronics circuits are an integral part of this textbook.
The PSpice circuit files listed in this text were developed using version 16.0. Continuous revision of software necessitates updates in simulation techniques.