Yes, you can implement the remote sensing using EN63A0 or any other Enpirion's regulator as shown below.
- The Ca branch and the Vsense pin must be connected at the last default output capacitor (Cout)
- Connect Ra branch at the load point to compensate for the voltage drop across the PCB
- Make sure Ra placement is near to EN63A0 not near to the load side to avoid having a long trace for VFB pin (where it is so sensitive to the noise).
1/ For the Vsense pin, we don't use it because we don't need the prebias feature, is it a problem?
2/ By connecting the Ra branch at the load point, how can I avoid any stability issue? Perhaps, using your stability tool anf adding trace RES and trace IND is sufficient but what about the parasitic capacitor of the trace?
No need to connect the VSENSE in your case since you don't use the pre-bias feature.
I only include that in my recommendation to make it general answer for any of Enpirion regulators.
Regarding the stability concern, based on the analysis that we did there is no worries in that connection where the control loop will not be effected.
Unfortunately the stability tool is not suitable for that analysis even if it shows that your system is stable where it always has Ra and Ca branches connected together at the same point and you can't separate them.
So i have attached EN63A0 LTSPICE (free spice tool from Analog devices, please click here to download) which will help you to do that analysis in time domain.
I have some issue running simulation with EN63A0. Running your test schematic, result are like image below :
If I replace input and output capacitors by ideal one (i.e. without ESL and ESR), simulation doesn't converge.
Could you help me please?
Final goal is to make stability simulation with long feedback track.
We don't recommend to use the ideal values but if you are facing Ltspice converge issue please adjust your LTSPICE setting as shown below.
Regarding the stability simulation, i have updated the circuit to add AC analysis and the simulation result as below. you can adjust the circuit based on your actual component values
Attached also is the simulation circuit with all the log and raw files, so you can have all same resulting and results as mine.
So sorry for late response.
Attached please find EN6337 LTSPICE model.
Regarding your question about the stability during the simulation when there are 3x EN63A0 connected in parallel:
Since the available simulation model doesn't support the parallel connection, then you can divided the total capacitance by 3 to make the equivalent system impedance close to what it looks like in actual life.
I have reviewed the LTspice tool and it looks it is limited and can't find the DC operating point to do the AC analysis.
So the only way to fix that, i need to create a new model that only represent the regulator transfer function, and to build that will take time.
So to check the stability quickly, you can use the stability tool to do the loop calculation and use the DC ltspice model to validate that the time domain analysis looks stable and there is no oscillation.
More of that, I'm trying to correlate LTspice simulation with your Excel file using the EN63A0 component but I'm not able to have same result.
My LTSpice simulation is below:
Resut is phase margin around 90°C at 37KHz:
Same circuit with Excel tool, I add the same capacitor:
Resut is phase margin around 62°C at 71KHz, even the shape of the curve is different:
Could you help me, please?
Hello @MBaqu ,
Happy new year to you too!
I trust more on the stability tool results, and i have created the AC model using PSPICE (OrCAD) as attached.
i have created a test circuit for the model so if you have OrCAD in your machine just open the .opj file and run the simulation from there.
Regarding the DC model: it is not good to do the small signal analysis with using the DC model because it is very hard for the simulation tool to get the steady state operating point so the tool can perform the small signal analysis.
So creating the small signal model as attached will help to do the stability analysis more accurate.