Chapter 3DiodesFunctionality and PhysicalOperation2025/11/27
Chapter 3 Diodes Functionality and Physical Operation 1 2025/11/27
2Content3.1TheldealDiode3.2TerminalCharacteristicsofJunctionDiodes3.3ModelingtheDiodeForwardCharacteristic3.4OperationintheReverseBreakdownRegionZenerDiodes3.5RectifierCircuits（整流电路）3.6LimitingandClampingCircuits（限幅与钳位电路）3.7PhysicalOperationofDiodes3.8SpecialDiodeTypes3.9 TheSPiCEDiodeModel andSimulationExamples2025/11/27
Content 3.1 The Ideal Diode 3.2 Terminal Characteristics of Junction Diodes 3.3 Modeling the Diode Forward Characteristic 3.4 Operation in the Reverse Breakdown Region—Zener Diodes 3.5 Rectifier Circuits （整流电路） 3.6 Limiting and Clamping Circuits （限幅与钳位电路） 3.7 Physical Operation of Diodes 3.8 Special Diode Types 3.9 The SPICE Diode Model and Simulation Examples 2025/11/27 2
3.1Linear and Nonlinear DevicesSofar,almostallthedeviceswehavelearntare linearMany signal-processingfunctions,however,are implemented by nonlinear devicesP马鸟鸟马马万NonlinearamplifierLinearamplifier2025/11/27
2025/11/27 3 3.1 Linear and Nonlinear Devices ⚫ So far, almost all the devices we have learnt are linear ⚫ Many signal-processing functions, however, are implemented by nonlinear devices Linear amplifier Nonlinear amplifier
43.1 Symbol and characteristicDiode (二极管)is the simplest and most fundamentalnonlinear circuit elementAnodeCathode---Reverse bias.------Forwardbias--O(a) Diode circuit symbol(b) i-vcharacteristicofthe ideal diodeOO+Vi>0=v=0V<0=i=0(d) Equivalent circuit(c)Equivalentcircuitinthe forward directioninthereverse directionNote: measures should be taken to limit theforward current and the reversevoltage!2025/11/27
2025/11/27 4 (a) Diode circuit symbol + v - i Anode Cathode (b) i–v characteristic of the ideal diode -Reverse bias- -Forward bias- i 0 v (c) Equivalent circuit in the reverse direction v < 0 i=0 i + v - i (d) Equivalent circuit in the forward direction i > 0 v =0 + v - Note: measures should be taken to limit the forward current and the reverse voltage! ⚫ Diode (二极管) is the simplest and most fundamental nonlinear circuit element 3.1 Symbol and characteristic
53.2 Junction Diodes and its CharacteristicsThemost important region is(mA)theboundarybetweenn-typeand p-type semiconductor,which is called pn junction(pn结)Metal contactMetal contactpn junction(v)71n-typep-typeOOsiliconsiliconCathodeAnodeThediodei-vrelationship2025/11/27
(v) The diode i–v relationship (mA) 2025/11/27 5 pn junction ⚫ The most important region is the boundary between n-type and p-type semiconductor, which is called pn junction(pn结) 3.2 Junction Diodes and its Characteristics