Lecture11-DiodeModels+2 - ECE 3040: Microelectronic...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
ECE 3040 - Dr. Ying Zhang Georgia Tech ECE 3040: Microelectronic Circuits Lecture 11 Reading: Jaeger 3.4-3.14, Pierret 9.2, Notes
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ECE 3040 - Dr. Ying Zhang Georgia Tech Recapture Simplified Diode Circuit Models 1.) Ideal Diode Model: a) The voltage across the diode is zero for forward bias. b) The slope of the current voltage curve is infinite for forward bias. c) The current across the diode is zero for reverse bias. V I Circuit Symbol
Background image of page 2
ECE 3040 - Dr. Ying Zhang Georgia Tech 2.) Constant Voltage Drop (CVD) Model: a) The voltage across the diode is a non-zero value for forward bias. Normally this is taken as 0.6 or 0.7 volts. b) The slope of the current voltage curve is infinite for forward bias. c) The current across the diode is zero for reverse bias. V I 0.6V + - V on Recapture Simplified Diode Circuit Models
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ECE 3040 - Dr. Ying Zhang Georgia Tech General Procedure: 1. Select a model for the diode (ideal or CVD). 2. Make an educated guess concerning the region of operation. 3. Analyze the circuit. 4. Check your initial assumption. Recapture Diode Circuit Analysis using Simplified Models
Background image of page 4
ECE 3040 - Dr. Ying Zhang Georgia Tech
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ECE 3040 - Dr. Ying Zhang Georgia Tech ± pn Junction Capacitance ± Diode Large-Signal Model ± Diode Applications Agenda
Background image of page 6
ECE 3040 - Dr. Ying Zhang Georgia Tech Models used for analysis of Diode Circuits Mathematical Model (previously developed) Graphical Analysis Ideal diode Model •Treat the diode as an ideal switch Constant Voltage Drop Model •Treat as an ideal switch plus a battery Large signal Model (model used by SPICE transient analysis) •multi-components •generally applicable Small Signal Model (model used by SPICE AC analysis) •easier math •valid only for limited conditions-ie small signals
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ECE 3040 - Dr. Ying Zhang Georgia Tech ± Forward and reverse-biased diodes have a capacitance associated with the pn junction. ± Under reverse bias (V A < 0), the depletion region width (W) increases since (Note: W = w d in the Jaeger’s book) ± Hence, the amount of charge in the depletion region also increases. ± Since the charge is changing with applied voltage, a capacitance results.
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/05/2009 for the course ECE 3040 taught by Professor Hamblen during the Spring '07 term at Georgia Institute of Technology.

Page1 / 25

Lecture11-DiodeModels+2 - ECE 3040: Microelectronic...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online