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Post-processor constant current line

Andrew Denham
Prodigy 60 points
Other Parts Discussed in Thread: TINA-TI

Hi, 

I am not too familiar with TINA, so a little help would  be gratefully received.

I have a simple V /  I plot  representing an output transistor with a protection circuit.

Essentially I have a Voltage controlled current source from a current source controlled by a transistor and  a voltage source (0 to 70V DC (VG1)). The VCCS dumps current into a 0.22 Ohm resistor (R1). there is feedback to the transistor from here.

That shows the kind of curve I would expect.

The thing I need to do is add a constant current line at I = 17A  and also I = 6.25A from V = 0 to 70. In addition I want to add a constant power dissipation curve for P= 250W from  V=10 to 70.

In the post processor I cannot access the X/Y function, it just says " XY plot only allowed in  trans or DC mode" which I seem to be in anyway.

I wrote a function for the power copied below but I get " Error in line 5" message when I try to create the function

{This is a template}
{Don't modify the functionname}
Function F(s);
Begin
 {Your expressions here}
  V1:=V_VG1[5,0];
 {The result value}
 F := 250/V1;
End;

Is this a syntax thing or is it not possible to do this in TINA?

  

    

  • 0
    TI__Genius 9775 points

    Andrew,


    I am a bit confused with what you try to do. Do you look for a way to plot "power" curve?

    If this is the case there is power meter (symbol) available similar to voltage meter and current meter within TINA-TI.

    Meters -> Power Meter.

    Herman

  • 0 in reply to Herman Theodorus
    TI__Mastermind 41310 points

    Andrew,

    Could you supply the .TSC file you are using? The post-processor in TINA-TI does not have the function definition available (it is in TINA industrial). Based on what you have described, however, you should be able to define a new plot in the post processor of (250/V_VG1(5,0)) which would give you the function you were describing.

    As for the constant current lines, I do not understand what you are looking for in the plot. Are you trying to add a limit function to the plot or the simulation? This can be done using the controlled source wizard. It is difficult to explain without seeing the .TSC file you are using, however.

    Britt

  • 0 in reply to Herman Theodorus
    Prodigy 60 points

    Sorry for delay, been out the office since Monday last.

    I have a simple two slope V-I limiter for an AF amp power stage. This gives me the slope for the limiter.

    The constant current lines I have plotted with the post processor (F:= 17) and (F:= 6.25) are the max current for the power transistor and the current at 40V for 250W dissipation.

    I am trying to overlay the power = 250W  curve over these to see where the V-I limiter is taking control.

    At I =17A, the curve above is irrelevant as the limiter "MUST" cut in, so essentially I am trying to add the 250/V curve from V= 14 (17.8A) to V = 66 (supply max) as a post processor curve.

    Is this possible in TINA?

  • 0 in reply to Britt Brooks - Online Design Tools
    Prodigy 60 points

    Hi TSC file attached.

    I = 17A line just shows I max for output device (F:=17) to show that limiter is active below that limit.

    I am trying to add P = 250W as max power for transistor represented by  VCCS controlled by VG1.

    This hopefully will allow me to verify that the limiter line does sit below the 250W curve along it whole length.

    I could print it and add the curve by hand but if it will be possible to add as  a post processor curve that would be helpful, as it is simple then to vary the zener voltage and the bias chain R3,4 & 6 to adjust the second part of the slope incrementally on screen.

    Maybe my syntax is wrong.

    I have tried plotting I against V

    F:= 250/ V_VG1(5,0); gives syntax error message.

    and also tried using a for-next loop to post plot the curve

    For v = 14 to 70   do F:= 250/v;

    just as  single line commands or in the advanced edit box.

    Maybe this does not come with the TI version?

    Amp_prot#2 - autosave 14-04-25 12_36.TSC