LTSpice学习笔记

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1、.LTspice1.变压器仿真的简单步骤：A.为每个变压器绕组绘制一个电感器B.采用一个互感(K)描述语句通过一条SPICE指令对其实施耦合：                                                          K1L1L21 K语句的最后一项是耦合系数，其变化范围介于0和1之间，1代表没有漏电感。对于实际电路，建议您采用耦合系数=1作为起点。 每个变压器只需要一个K语句；LTspice为一个变压器内部的所有电感器应用了单一耦合系数。下面所列是上述语句的等效语句:                             

2、                             K1L1L21                                                           K2L2L31                                                           K3L1L31C.采用“移动”(F7)、“旋转”(Ctrl+R)和“镜像”(Ctrl+E)命令来调节电感器位置以与变压器的极性相匹配。添加K语句可显示所含电感器的调相点。D.LTspice采用个别组件值(在本场合中为个别电感器的电感)而非变压器的匝数

3、比进行变压器的仿真。电感比与匝数比的对应关系如下： 电感至匝数比例如：对于1:3和1:2的匝数比，输入电感值以产生1:9和1:4的比值：2.一般来说压是对地，如果你想知某元件俩端的电压该如何呢？ 设一参考点，先点小人，然后在电路图的空白处点右键，找黑白电笔Set probe reference，也可从VIEW找。按键盘上ESC可去黑白电笔。3.Die Impulsantwort 脉冲响应。4.TocreateanLTspicemodelofagivenMOSFET,youneedtheoriginaldatasheetandthepSPICEmodelofthatM

4、OSFET. TheparametersneededtodefineaMOSFETinLTspiceareasfollows:Rg        GateohmicresistanceRd        Drainohmicresistance(thisisNOTtheRDSon,buttheresistanceofthebondwire)Rs        Sourceohmicresistance.Vto      Zero-biasthresholdvoltage.Kp–     TransconductancecoefficientLambda Change

5、indraincurrentwithVdsCgdmax Maximumgatetodraincapacitance.Cgdmin  Minimumgatetodraincapacitance.Cgs      Gatetosourcecapacitance.Cjo       Parasiticdiodecapacitance.Is         Parasiticdiodesaturationcurrent.Rb        Bodydioderesistance.Rg,RdandRsaretheresistancesofthebondwiresconnect

6、ingthedietothepackage...VtoistheturnonvoltageoftheMOSFET.KpisthetransconductanceoftheMOSFET.Thisdeterminesthedraincurrentthatflowsforagivengatesourcevoltage.LambdaisthechangeindraincurrentwithdrainsourcevoltageandisusedwithKptodeterminetheRDSon.CgdmaxandCgdminaretheminimumandmaximumval

7、uesofthegatedraincapacitanceandarenormallygraphedintheMOSFETdatasheetasCrss.Thecapacitanceofacapacitorisinverselyproportionaltothedistancebetweenitsplates.WhentheMOSFETisturnedon,distancebetweenthegateandtheconductingchannelofthedrainisequaltothethicknessoftheinsulatinggateoxidelayer