Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

I need calculate and measure C2, C3,C1 for active inductor

Status
Not open for further replies.

noor84

Member level 5
Joined
Dec 27, 2017
Messages
90
Helped
0
Reputation
0
Reaction score
0
Trophy points
6
Activity points
688
Dear friends,

I am working to design active inductor using the circuit shown in Fig.1
Figure 2 below is the small signal of fig.1,
Please, anyone, explain to me what is C1, C2, C3 and
How can I calculate and measure these values?

I am looking to hear from you as soon as possible.
Thanks


1.png
2.png
 

The RC networks create a similar time constant that you'd get from an inductor, or LR network.

It appears that your schematics present various RC arrangements. I suppose they produce similar voltage waveforms (although perhaps at lower power levels) to the behavior of an inductor.

As a clue to calculating values, go back to the simple formulae:

1 Henry, 1 Ohm, t.c. =1 sec. (C* R)

1 Farad, 1 Ohm, t.c. =1 sec. (L/ R)
 
  • Like
Reactions: noor84

    noor84

    Points: 2
    Helpful Answer Positive Rating
I didn't understand please explain to me.
 

The capacitors are representing MOSFET Cds respectively Cds + Cgs. You'll find out by sketching a complete equivalent circuit with all transistor capacitances.

Not quite sure what you mean with "calculate and measure" as the values are set by the transistor technology and geometry parameters.
 

Looking at your diagram I confess had the impression you plan to put capacitors in the upper schematic so as to form an active inductor (as modelled by your lower schematic). Now I see FvM explains how the lower schematic models capacitance in the mosfet gates of the upper schematic.

Below is my simulation to serve as a visual aid to my post #2. It
shows how a capacitor can produce the effect of an inductor when a square wave is applied.

1) Simple demo of inductor.

2) Showing how a capacitor (and resistors) can be made to mimic inductor behavior.

3) Gyrator (active inductor) found in the menu of Falstad's circuit simulator. (I moved the 1k load to be attached to ground.) It has an RC network which acts as an integrator similar to the previous circuit.

inductor demo vs RC mimic inductor vs active inductor (gyrator).png

Notice how they all output a similar waveform. They all demonstrate an identical time constant.
 

noor84 - I don`t know if you are required to use the shown schematics.
If not - be aware that there are more simple and more exact circuit arrangements available for an active inductor .
 

There are many ways to implement an active inductor. However, the presented type was developed to increase the speed of the active inductor, and to improve the silicon efficiency.
Here you can find more information:
**broken link removed**
 
  • Like
Reactions: FvM

    FvM

    Points: 2
    Helpful Answer Positive Rating
Please, May you give me one simple circuit for the active inductor that can I build in ADS simulator?
I would like to learn how to measure Q, L, Power consuming...etc. Then I will go to improve these parameters.

thanks for your help in advance.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top