• University of Colorado, Boulder

• ECEN 5797

Homework Assignment #1: Boost Converter Simulation

Introduction

This assignment is an introductory simulation problem, concerning

LTspice simulation of a boost dc-dc converter. To get started, do the

following:

1. Download and install LTspice on your computer. Windows and

Macintosh versions of LTspice IV are available at the following site:

http://www.linear.com/designtools/software/

2. Download and unzip the boost converter and associated files from the

link below, and save them in a working directory on your local disk.

Boost.zip

3. Open the file boost.asc using LTspice. Press the run button to run a

simulation of the turn-on transient of this circuit. It should take 10-

20 seconds for the simulation to run (depending on your computer

speed). When the simulation is done, you can click on a node in the

schematic to plot the voltage at that node. If you move the mouse

over an element such as the inductor, it turns into a current probe

symbol; you can then click to plot the current in that element.

Explore the waveforms of the converter, including the output

voltage, the inductor current, and the switch node voltage.

Questions

For the numerical answers below, you should enter your answer with

an accuracy of +/- 1%. For efficiency, your answer should have an

accuracy of at least +/- 0.1% of efficiency.

1. What is the steady-state average output voltage (expressed in volts)?

2. What is the steady-state average inductor current (in amps)?

3. What is the steady-state output power (in watts)?

4. What is the average power drawn out of the input source Vg during

steady-state operation of the converter (in watts)?

5. What is the average power consumption of the gate driver (in watts)?