Hi there!
I have a rather tricky question (or it kept me busy for a few days now at least).
I want to analyze a simple temperature measurement circuit using an NTC as the sensing device.
I found nice detailed information about creating NTCs in SPICE programs and I created my device which works just fine.
However I want to take the model to the next level by adding the tolerance of the NTC parameters. Adding deviation to a part is easy, as far as you only want to do it with resistances or capacitors, well I want to do it with parameters instead!
The NTC model which I use is attached to this post.
Now my problem in detail, and how I tried to solve it (but did not succeed):The parameters which this small subcircuit uses are only used to adjust the output voltage of a voltage source, therefore they do not appear as resistors or capacitors in the circuit. If the would I could simply add the DEV to the RC parts and be done with the job.
What I tried:
The first thing that came to my mind was to simply add the DEV=1% after the parameter value like this
.PARAM R_25 10k DEV=1%
This did not work because Pspice thought that I am trying to redefine DEV.
The other thing was to add resistors which are connected on both their pins to GND. In this case it is possible to add the DEV to the resistor´s .MODEL directive, but I was unable to use the resistor´s value in the equation later.
I tried other silly things too but I failed to achieve my goal (or the plot of the maximum deviation and the nominal velue aligned perfectly, which basically means that there was no deviation)
I would really appriceate any input on this matter.
Thank you!
I have a rather tricky question (or it kept me busy for a few days now at least).
I want to analyze a simple temperature measurement circuit using an NTC as the sensing device.
I found nice detailed information about creating NTCs in SPICE programs and I created my device which works just fine.
However I want to take the model to the next level by adding the tolerance of the NTC parameters. Adding deviation to a part is easy, as far as you only want to do it with resistances or capacitors, well I want to do it with parameters instead!
The NTC model which I use is attached to this post.
Now my problem in detail, and how I tried to solve it (but did not succeed):The parameters which this small subcircuit uses are only used to adjust the output voltage of a voltage source, therefore they do not appear as resistors or capacitors in the circuit. If the would I could simply add the DEV to the RC parts and be done with the job.
What I tried:
The first thing that came to my mind was to simply add the DEV=1% after the parameter value like this
.PARAM R_25 10k DEV=1%
This did not work because Pspice thought that I am trying to redefine DEV.
The other thing was to add resistors which are connected on both their pins to GND. In this case it is possible to add the DEV to the resistor´s .MODEL directive, but I was unable to use the resistor´s value in the equation later.
I tried other silly things too but I failed to achieve my goal (or the plot of the maximum deviation and the nominal velue aligned perfectly, which basically means that there was no deviation)
I would really appriceate any input on this matter.
Thank you!