【正文】 附件A：三極管模型參數(shù)附件B：PSpice常用的全局函數(shù)附件C：ABM行為器件庫(kù)的應(yīng)用實(shí)例一、Modeling voltagecontrolled and temperaturedependent resistorsVoltagecontrolled resistorIf a Resistance vs. Voltage curve is available, a lookup table can be used in the ABM expression. This table contains (Voltage, Resistance) pairs picked from points on the curve. The voltage input is nonlinearly mapped from the voltage values in the table to the resistance values. Linear interpolation is used between table values.Let’s say that points picked from a Resistance vs. Voltage curve are:VoltageResistance2550100The ABM expression for this is shown in Figure 1.Figure 1 Voltage controlled resistor using lookup tableTemperaturedependent resistorA temperaturedependent resistor (or thermistor) can be modeled with a lookup table, or an expression can be used to describe how the resistance varies with temperature. The denominator in the expression in Figure 2 is used to describe mon thermistors. The TEMP variable in the expression is the simulation temperature, in Celsius. This is then converted to Kelvin by adding . This step is necessary to avoid a divide by zero problem in the denominator, when T=0 C.NOTE: TEMP can only be used in ABM expressions (E, G devices).Figure 3 shows the results of a DC sweep of temperature from 40 to 60 C. The yaxis shows the resistance or V(I1:)/1A.Figure 2 Temperature controlled resistorFigure 3 PSpice plot of Resistance vs. Temperature (current=1A)Variable Q RLC networkIn most circuits the value of a resistor is fixed during a simulation. While the value can be made to change for a set of simulations by using a Parametric Sweep to move through a fixed sequence of values, a voltagecontrolled resistor can be made to change dynamically during a simulation. This is illustrated by the circuit shown in Figure 5, which employs a voltagecontrolled resistor. Figure 4 Parameter sweep of control voltageThis circuit employs an external reference ponent that is sensed. The output impedance equals the value of the control voltage times the reference. Here, we will use Rref, a 50 ohm resistor as our reference. As a result, the output impedance is seen by the circuit as a floating resistor equal to the value of V(Control) times the resistance value of Rref. In our circuit, the control voltage value is stepped from volt to 2 volts in volt steps, therefore, the resistance between nodes 3 and 0 varies from 25 ohms to 100 ohms in 25 ohmsteps.Figure 5 Variable Q RLC circuitA transient analysis of this circuit using a ms wide pulse will show how the ringing differs as the Q is varied.Using Probe, we can observe how the ringing varies as the resistance changes. Figure 6 shows the input pulse and the voltage across the capacitor C1. Comparing the four output waveforms, we can see the most pronounced ringing occurs when the resistor has the lowest value and the Q is greatest. Any signal source can be used to drive the voltagecontrolled resistance. If we had used a sinusoidal control source instead of a staircase, the resistance would have varied dynamically during the simulation.54 / 54。注意：PSpice支持的模型參數(shù)含義，在軟件光盤的下面文件中有詳細(xì)的介紹：光盤\Document\在附件A中舉出三極管的模型參數(shù)。另外一種方法是直接從開始菜單中打開PSpice Model Editor，然后直接打開相對(duì)應(yīng)的庫(kù)檔，選中相應(yīng)的器件然后開始修改，這樣將會(huì)直接影響以后該器件的模型。 編輯器件模型在Capture的Schematic中，選中需要編輯的器件，點(diǎn)擊EditPspice Model，系統(tǒng)將會(huì)自動(dòng)到PSpice的模型庫(kù)中查找該器件的模型，并彈出如下窗口：通過(guò)修改窗口中的文本，并保存退出，即已經(jīng)修改了該模型。但波形描述文件中一定要有與信號(hào)源輸出端節(jié)點(diǎn)名稱相同的信號(hào)名。波形描述文件中的信號(hào)名個(gè)數(shù)與信號(hào)源位數(shù)(即信號(hào)源輸出端節(jié)點(diǎn)名個(gè)數(shù))不一定相等。(2) 多位信號(hào)源FILESTIMn：這種信號(hào)源有16或32位輸出，因此，需從波形設(shè)置文件中讀取多組資料。若SIGNAME參數(shù)設(shè)置為Reset，作為該信號(hào)源的激勵(lì)信號(hào)波形。下面以前面例3所示波形描述文件的調(diào)用為例，說(shuō)明與該參數(shù)設(shè)置有關(guān)的幾個(gè)問(wèn)題。1. FILENAME（波形描述文件名）本項(xiàng)參數(shù)的作用是指定調(diào)用那一個(gè)波形描述檔。B、FILESTIMn信號(hào)源波形設(shè)置FILESTIMn參數(shù)設(shè)置由于FILESTIMn類信號(hào)源波形由波形描述文件中資料確定，因此其信號(hào)設(shè)置比較簡(jiǎn)單。最后一個(gè)字符用于描述文件頭中最后一個(gè)一般信號(hào)RW的信號(hào)邏輯電平。由于文件頭中包括5個(gè)一位信號(hào)，兩個(gè)HEX分組信號(hào)，因此在波形描述部分，時(shí)間值后面邏輯電平設(shè)置項(xiàng)共有7個(gè)字符。在檔頭中設(shè)置了時(shí)間倍乘因子值。例3：下述文件內(nèi)容描述了13個(gè)信號(hào)的波形。如果邏輯電平值設(shè)置為X、Z、R或F，則分組內(nèi)的每一個(gè)信號(hào)均取該設(shè)置值。(2) 邏輯電平值：波形描述部分邏輯電平值可采用的字符及其含義如表8所示。時(shí)間值可以用絕對(duì)模式(如45ns，)，或相對(duì)模式(如+5ns，+1e9等)表示。每一行格式為：時(shí)間值 邏輯電平值其中時(shí)間值與邏輯電平值之間應(yīng)該用空格分開。這兩部分之間至少用一個(gè)空行隔開。對(duì)高、低電平值，一般信號(hào)對(duì)應(yīng)的是二進(jìn)制數(shù)，而一個(gè)OCT分組和HEX分組分別對(duì)應(yīng)于一個(gè)8進(jìn)制數(shù)和16進(jìn)制數(shù)。在HEX右側(cè)括號(hào)內(nèi)必須有4個(gè)信號(hào)名。在后一種情況下，相應(yīng)的4個(gè)信號(hào)名合為一組，用關(guān)鍵詞HEX作為其標(biāo)志名。(3)OCT和HEX信號(hào)名組：PSpice可以用一個(gè)8進(jìn)制數(shù)表示3個(gè)信號(hào)的邏輯電平值，用一個(gè)16進(jìn)制數(shù)表示4個(gè)信號(hào)的邏輯電平值。每一行字符數(shù)不得超過(guò)300個(gè)。(2)一般信號(hào)名列表：在文件頭的信號(hào)名列表區(qū)中，用二進(jìn)制數(shù)描述的信號(hào)只需列出信號(hào)名，不同信號(hào)名之間應(yīng)該用空格或逗號(hào)等分隔符隔開。波形描述部分的時(shí)間值等于設(shè)置值乘“時(shí)間倍乘因子值”。其一般格式如下所示：TIMESCALE＝時(shí)間倍乘因子值信號(hào)名1，…信號(hào)名nOCT(bit2信號(hào)名…bito信號(hào)名)HEX(bit3信號(hào)名…bito信號(hào)名)(1)時(shí)間倍乘因子值：這是任選項(xiàng)參數(shù)。A、激勵(lì)信號(hào)波形描述文件格式波形描述檔由兩個(gè)部分組成。如果描述波形的數(shù)據(jù)量較大，或者激勵(lì)信號(hào)是另一次邏輯模擬的輸出波形，甚至是另一個(gè)模擬軟件的輸出結(jié)果，采用波形描述檔是一種比較好的方法。表7 指數(shù)信號(hào)電平值與參數(shù)的關(guān)系時(shí)間范圍電平值0td1v1td1td2v1+(v2v1)(1exp((TIMEtd1)/tc1)td2TSTOPv1+(v2v1)((1exp((TIMEtd1)/tc1)(1exp((TIMEtd2)/tc2))注：表中TSTOP為瞬態(tài)分析中參數(shù)Final Time的設(shè)置值。然后又以tc2為時(shí)常數(shù)，按指數(shù)規(guī)律變化至v1。圖中所示波形對(duì)應(yīng)的參數(shù)如圖中所示。描述該信號(hào)要有6個(gè)參數(shù)，如表6所示。表5 描述調(diào)頻信號(hào)的參數(shù)參數(shù)含義單位內(nèi)定值voff偏置電壓伏特?zé)o內(nèi)定值vampl峰值振幅伏特?zé)o內(nèi)定值fc載頻赫茲1/TSTOPfm調(diào)制頻率赫茲1/TSTOPmod調(diào)制因子0注：表中TSTOP是瞬態(tài)特性分析中參數(shù)Final Time的設(shè)置值。調(diào)頻信號(hào)與這些參數(shù)之間的關(guān)系為：voff+vampl*sin(2*fc*TIME+mod*sin(2*fm*TIME))下圖為一個(gè)調(diào)頻信號(hào)波形實(shí)例。若阻尼因子與偏置值均為0，則調(diào)幅信號(hào)成為標(biāo)準(zhǔn)的正弦信號(hào)，但是在進(jìn)行36節(jié)介紹的AC分析時(shí)，本信號(hào)并不起作用。調(diào)幅正弦信號(hào)波形(例)表3 描述調(diào)幅信號(hào)的參數(shù)參數(shù)名稱單位內(nèi)定值voff偏置值伏特?zé)o內(nèi)定值vampl峰值振幅伏特?zé)o內(nèi)定值freq頻率赫茲1/TSTOPphase相位度0df阻尼因子1/秒0td延遲時(shí)間秒0注：表中TSTOP為瞬態(tài)分析中參數(shù)Final Time的設(shè)置值。表4給出了調(diào)幅正弦信號(hào)波形的變化與這6個(gè)參數(shù)的關(guān)系。分段線性信號(hào)波形（例）（3）.調(diào)幅正弦信號(hào)（SIN: Sinusoidal Waveform）描述調(diào)幅正弦信號(hào)涉及6個(gè)參數(shù)。下圖是一個(gè)分段線性信號(hào)波形實(shí)例。表2脈沖信號(hào)電平值與參數(shù)的關(guān)系時(shí)間脈沖電平0v1tdv1td+trv2td+tr+pwv2