113.3Simplified Diode Modelip(mA)1211The exponentialStraight line B10characteristic1Ideal9Slope+TD87VDO6Up543Straight line A2O1.000.20.40.6个0.8UD(V)VpoPiecewise-linearmodeloftheEquivalentcircuitrepresentationdiodeforwardcharacteristic2025/11/27
2025/11/27 11 Equivalent circuit representation. 3.3 Simplified Diode Model Piecewise-linear model of the diode forward characteristic
123.3Constant-Voltage-DropModelipC+VIdeal←VD=0.7V→UpVD=0.7V0UDThe constant-voltage-dropmodel of thediodeforwardcharacteristicsanditsequivalent-circuitrepresentation.2025/11/27
2025/11/27 12 The constant-voltage-drop model of the diode forward characteristics and its equivalent-circuit representation. 3.3 Constant-Voltage-Drop Model
133.3Small-Signal* Model(mA)(n = 2)2.01.8IncrementalresistanceTangentatQ1.6Slope1.4ia(0)nlBiaspoint(n = 1,2)1.2olp1.0DC0.80.60.4ip(t)0.2M0.75Up(V)0.550.600.65700.80Da(r)Va(t)olVatd+Vp*The signal amplitudeis sufficiently small such that the excursion at Qalong the i-v curveis limitedto a short, almostlinear segment.2025/11/27
2025/11/27 13 3.3 Small-Signal* Model rd (n = 2) = , (n =1,2) I nV r DQ T d Incremental resistance *The signal amplitude is sufficiently small such that the excursion at Q along the i-v curve is limited to a short, almost linear segment
143.3High-FrequencyModel>RelatedtothebiasTabIe3.2HIGH-FREQUENCYSMALL-SIGNALMODELOFTHEDIODEBias point: Io. VpranVellpCa(TTVIDVoCo/l1forVo<0VoC=2Co.forVo>02025/11/27
2025/11/27 14 ➢Related to the bias 3.3 High-Frequency Model
153.4Zener Diode Model11+720ZVVzSlopIr(testcurrentOOAIAVVz = Vzo + IzrzAV=AlrzThe diodei-vcharacteristicwiththebreakdown regionshown insomedetail2025/11/27
2025/11/27 15 3.4 Zener Diode Model The diode i–v characteristic with the breakdown region shown in some detail Z Z Z Z V = V + I r 0