#68 measure sweeping the temperature

[roberto]

I am sweeping the tempareture and i wouzld like to get a measure of the signal.
I have a bandgap reference and i would like to measure the maximum value of bandgap voltage, sweeping the temperature.
.measure dc ymax MAX v(vbg) from=-40 to=150

But i get this error
Error: no such vector as time, frquency or v-sweep.

Error: measure ymax max v(vbg) : out of interval
meas dc ymin max v(vbg) from=-40 to=150 failed!

[Giles Atkinson]

In that line, there is nothing to tie the numbers -40,150 to temperature. I think they will be treated as DC voltages. Manual 1.3,2 shows temperature sweeping, is that what you are using?

It may be that after such a sweep, the values in .measure should be automatically applied to temperature , but that is not happening. That would be a bug, and bugs must usually be reproduced as a first step. So please post a complete netlist that demonstrates the problem.

Meanwhile, you should be able to do the measurement with scripting, by adding a .control section to the netlist.

[roberto]

Here the netlist. for transient it works fine.

[Giles Atkinson]

Thanks, someone will take a look. If me, it may take a few days.

[Holger Vogt]

Currently only
meas dc ...
with scale vector v-sweep is supported (no i-sweep, res-sweep, nor temp-sweep).

I will have a look if this may be enhanced without too much effort, so to become available in ngspice-42.

[Holger Vogt]

I have got a fix, and its output is

******
** ngspice-41+ : Circuit level simulation program
** Compiled with KLU Direct Linear Solver
** The U. C. Berkeley CAD Group
** Copyright 1985-1994, Regents of the University of California.
** Copyright 2001-2023, The ngspice team.
** Please get your ngspice manual from https://ngspice.sourceforge.io/docs.html
** Please file your bug-reports at https://ngspice.sourceforge.io/bugrep.html
** Creation Date: Dec  7 2023   23:23:03
******
Start finished after 0.12 seconds.

Note: Compatibility modes selected: hs a

Warning: m=xx on .subckt line will override multiplier m hierarchy!

Warning: redefinition of .subckt sky130_fd_pr__pnp_05v5_w0p68l0p68, ignored

Circuit: ** sch_path: /home/roberto/documents/circuits/bandgap_2/tb_bg.sch

Source Deck finished after 1.59 seconds.
option SCALE: Scale is set to 1e-06 for instance and model parameters
Prepare Deck finished after 1.61 seconds.
Doing analysis at TEMP = 27.000000 and TNOM = 27.000000

Parse finished after 1.63 seconds.
Using SPARSE 1.3 as Direct Linear Solver
Device Setup finished after 1.63 seconds.

No. of Data Rows : 1
ASCII raw file "tb_bg_op.raw"
op finished after 1.63 seconds.
Doing analysis at TEMP = 27.000000 and TNOM = 27.000000

Parse finished after 1.63 seconds.
Using SPARSE 1.3 as Direct Linear Solver
Device Setup finished after 1.65 seconds.
op finished after 1.65 seconds.

No. of Data Rows : 191
ASCII raw file "tb_bg_dc.raw"
ymax                =  1.203137e+00 at=  2.700000e+01
ngspice 1 -> 

A little more testing is due before uploading.

[Holger Vogt]

I have uploaded a fix to ngspice git branch pre-master-42.

[roberto]

Thank you very much, i will wait for the official release