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https://designers-guide.org/forum/YaBB.pl Modeling >> Behavioral Models >> Behavioural modelling in HSpice https://designers-guide.org/forum/YaBB.pl?num=1140777972 Message started by aamar on Feb 24th, 2006, 2:46am |
Title: Behavioural modelling in HSpice Post by aamar on Feb 24th, 2006, 2:46am Hallo, Is there a way to describe behavioural model to be used in HSpice (the model should include conditional statments)? (something like SpectreHDL with Spectre netlists). i.e. I have a voltage controlled current source which depends on the Gate-Source voltage of a transistor, where the source is not constantly defined since it depends on the direction of the current in the transistor. Best regards, amar |
Title: Re: Behavioural modelling in HSpice Post by Geoffrey_Coram on Feb 24th, 2006, 6:13am Some HSpice licenses include hsp-vacomp for Verilog-A compilation (not the "basic" hspice, but a somewhat more expensive one). Also, HSpice allows fairly general expressions in their dependent source equations; you can include absolute values, and you may be able to include conditional expressions '(vds>0) * expr1 + (vds<=0) * expr2' |
Title: Re: Behavioural modelling in HSpice Post by aamar on Mar 6th, 2006, 6:38am Dear Mr. Coram, Thanks for your reply, I don't have the -vacomp license. and since you replied and I am searching in the Hspice manual for such conditional commands but I can't find it, can you tell me plz what exactly should I search for. By the way, the only conditional possibility is included in N,PPWL sources, but it is not helpful in my case because the expression which I am using is depending on two values (i.e. bsource (voltage, current)) and in the G vccs PWL source I think I can only define the current depending on one parameter. The other solution which I am trying is a two position ideal switch, which is controlled with the source drain voltage and it should switch between two models (subcircuits). Note: I have done it already with spectreHDL and spectre. Thanks again aamar |
Title: Re: Behavioural modelling in HSpice Post by Geoffrey_Coram on Mar 15th, 2006, 6:02am Without knowing exactly what you are trying to do, I'm having a little trouble helping. I'm a little concerned that putting in conditional statements may introduce a discontinuity that you might not really want. If you want something that depends on both V and I, you could certainly convert the I to a V using a CCVS, and then combine the two Vs with a two-input VCVS. Also, consider using a voltage-controlled resistor. I found this equation Rpure 3 4 'Rsh/mf*(l-dl)/(w-dw)*tfacp*(1+pvcp1*(tanh(pvcp2*abs(v(3,4)/(l-dl))+pvcp3)-tanh(pvcp3)))' in an HSpice model file. HSpice certainly gives you enough rope to hang yourself. :) |
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