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31st March 2012, 03:21 #1
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Memristor simulation in HSPICE
Hi,
I am working with memristors and have been trying to simulate their behavior using HSPICE without success. Am using the nonlinear dopant drift model from http://www.radioeng.cz/fulltexts/2009/09_02_210_214.pdf
Just to confirm that the SPICE code I was using was correct I tried it in Pspice, as the testing in the above paper was done on Pspice. It worked on Pspice and I was able to simulate the code, i.e., observe the hysteresis, using it. The code I used in PSpice is very similar to the one available at:
http://www.edaboard.com/thread224608.html
Am including it here (from the above thread, but my code is similar):
PSpice Code:
* Ron, Roff  Resistance in ON / OFF States
* Rinit  Resistance at T=0
* D  Width of the thin film
* uv  Migration coefficient
* p  Parameter of the WINDOWfunction
* for modeling nonlinear boundary conditions
* x  W/D Ratio, W is the actual width
* of the doped area (from 0 to D)
*
.SUBCKT memristor Plus Minus PARAMS:
+ Ron=100 Roff=16K Rinit=11K D=10N uv=10F p=10
* DIFFERENTIAL EQUATION MODELING *
Gx 0 x value={ I(Emem)*uv*Ron/D^2*f(V(x),p)}
Cx x 0 1 IC={(RoffRinit)/(RoffRon)}
Raux x 0 1T
* RESISTIVE PORT OF THE MEMRISTOR *
Emem plus aux value={I(Emem)*V(x)*(RoffRon)}
Roff aux minus {Roff}
*Flux computation*
Eflux flux 0 value={SDT(V(plus,minus))}
*Charge computation*
Echarge charge 0 value={SDT(I(Emem))}
* WINDOW FUNCTIONS
* FOR NONLINEAR DRIFT MODELING *
*window function, according to Joglekar
.func f(x,p)={1(2*x1)^(2*p)}
*proposed window function
;.func f(x,i,p)={1(xstp(i))^(2*p)}
.ENDS memristor
Xmemrist aa 0 memristor
Vtest aa 0 SIN(0 1.2V 1 0 0 0)
.tran 0 3s 0 3m skipbp
.probe
.end

But when I try to use it with HSPICE it does not work, i.e., I am unable to observe the hysteresis when plotting the IV characteristics. The IV plot is linear, representing a simple resistor.
My HSPICE code is shown below:
* MEMRISTOR
* Ron, Roff  Resistance in ON / OFF States
* Rinit  Resistance at T=0
* D  Width of the thin film
* uv  Migration coefficient
* p  Parameter of the WINDOWfunction
* for modeling nonlinear boundary conditions
* x  W/D Ratio, W is the actual width
* of the doped area (from 0 to D)
*
.SUBCKT memristor Plus Minus
+ Ron=100 Roff=16K Rinit=11K D=10N uv=10F p=10
* DIFFERENTIAL EQUATION MODELING *
. PARAM f(x,p)= '1pow((2*x1),(2*p))'
Gx 0 x value='I(Emem)*uv*Ron/pow(D,2)*f(V(x),p)'
Cx x 0 1 IC='(RoffRinit)/(RoffRon)'
Raux x 0 1T
* RESISTIVE PORT OF THE MEMRISTOR *
Emem plus aux value='I(Emem)*V(x)*(RoffRon)'
Roff aux minus Roff
*Flux computation*
*Eflux flux 0 value={SDT(V(plus,minus))}
*Charge computation*
*Echarge charge 0 value={SDT(I(Emem))}
* WINDOW FUNCTIONS
* FOR NONLINEAR DRIFT MODELING *
*window function, according to Joglekar
*.func f(x,p)={1(2*x1)^(2*p)}
*proposed window function
*;.func f(x,i,p)={1(xstp(i))^(2*p)}
.ENDS memristor
Xmemrist aa 0 memristor Ron=100 Roff=16K Rinit=11K D=10N uv=10F p=10
Vtest aa 0 SIN(0 1.2V 1 0 0 0)
.tran 100U 5
.plot tran V(aa) I(Vtest)
.option list node post=2 ingold=2
.end

The changes I made from Pspice to HSPICE are:
1. changed the 'window' function definition from Pspice to HSPICE equivalent,
2. commented the flux and charge computation sections, as HSPICE does not have a 'SDT' equivalent function and they are not needed to observe the memristor characteristics.
Am not able to figure out the issue, any help would be useful.

Thanks,
Basawaraj

31st March 2012, 03:21

13th April 2012, 20:51 #2
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Re: Memristor simulation in HSPICE
Hi,
Came up with a idea to fix my HSPICE code. For this I have to access the nodes inside the subcircuit. This is pretty easy in HSPICE, but am not sure how to do this in PSPICE.
I tried by changing my memristor symbol, that is added another port at node "aux" of the subcircuit so that I could probe it. As I am only interested in probing it this port was left unconnected in the circuit. The simulation failed because this node was left unconnected.
Hence, is it possible to probe nodes inside a PSPICE subcircuit? If so how?

28th May 2012, 22:42 #3
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Re: Memristor simulation in HSPICE
Hi,
Found a solution, have to turn off the runlvl parameter, i.e., set it to zero

22nd October 2012, 15:45 #4
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Re: Memristor simulation in HSPICE
I tried to run your posted code and turned off runlvl as you suggested,
.option list node post=2 ingold=2 runlvl=0
However, it did not work as I was not able to observe hysteresis. Anything else should I modify to get it working? Do you mind to post your final working HSPICE code? Thanks in advance.

22nd October 2012, 15:45

4th November 2012, 22:21 #5
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Re: Memristor simulation in HSPICE
Hi basawaraj,
Would you mind sharing your final HSPICE description? For any reason, no matter I made the changes you recommended it does not work for me. We are using Synopsys' HSPICE 2010.
Thanks in advance!

27th May 2013, 21:21 #6
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Re: Memristor simulation in HSPICE
Hi,
I tested this code with hspice(V2008).At first it doesn't work and give me this error " **warning** (c:\users\sh.k\desktop\mem12.sp:17) ignore unrecognizable command card ." and then I checked every thing in this program. Finally I think I found what is wrong!
In this line: ". PARAM f(x,p)= '1pow((2*x1),(2*p))' " you should be delete the spice between "." and "PARAM". you do it and check again!
By the way, in Hspice it is better that "STD" changed to "INTEG".

Shahab
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28th May 2013, 04:15 #7
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Re: Memristor simulation in HSPICE
Shahab, Thank you so much for the reply! I'm going to give ti a try!

14th May 2014, 20:44 #8
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Re: Memristor simulation in HSPICE
Hi onnes,
After all the changes suggested by u people i m getting just opposite curve of hysteresis, i.e., instead of 1st and 2nd quadrant i m getting it into 2nd and 4th quadrant. i have used the same code given above. Please help me with this.
Thanking you in anticipation.

14th May 2014, 20:44

2nd October 2014, 19:29 #9
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Re: Memristor simulation in HSPICE
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