Hi all , How can i Check current at any node in this circuit ?

Piyush Dwivedi

08/21/2023, 7:10 PM

Hi all , How can i Check current at any node in this circuit ?

Krzysztof Herman

08/22/2023, 6:06 AM

Hi @Piyush Dwivedi, the common way to do so is to put a voltage source of value 0 (Vx for example) and then just run the simulation and print or plot I(Vx)

Stefan Schippers

08/22/2023, 7:09 AM

In addition if you add the instruction

.option savecurrents

(before the .control section) all MOS drain/source/body currents are saved.

Copy code

.option savecurrents
.control
...
...
tran 0.1n 100n
remzerovec
write xxxx.raw
.endc

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Stefan Schippers

08/22/2023, 7:11 AM

there is no 'node current' concept. current is referred to a circuit branch. xschem has the

devices/ammeter.sym

symbol that is actually a 0V voltage source. Add these ammeters in any branch you want the current to be saved.

Stefan Schippers

08/22/2023, 7:40 AM

If you use the

.option savecurrents

and after a .op simulation you go to

Simulation->Annotate operating point into schematic

and ensure

View->Show hidden texts

is enabled xschem willl show the MOS currents in the schematic directly:

👍 1

🌍 1

Piyush Dwivedi

08/22/2023, 9:04 AM

@Stefan Schippers How to check noise of this LDO circuit ?

Stefan Schippers

08/22/2023, 4:45 PM

I am not very expert on noise simulations, so may be some other sky130 user might answer, or you can try to go through the ngspice user manual.

Piyush Dwivedi

08/22/2023, 4:51 PM

okay stefan thank you for this much help

Piyush Dwivedi

08/22/2023, 4:54 PM

@Stefan Schippers hey stefan could you please tell me how to sweep line regulation and load regulation for LDO circuit

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