Anyone see this type of vco ?

[beixujia]

Anyone see this type of vco ?
can you give me some paper about it ?
I have seen many company use this type of vco,
but I havn't find the paper about this vco.

thank you very much.

 

[BradtheRad]

As drawn it has no components that produce time-related behavior (such as capacitors and coils).

I believe it is a voltage-controlled amplifier. The mosfet at left controls current through the network at right.

Could it oscillate by means of gate capacitances in the mosfets? The network at right shows some resemblance to an astable multivibrator. Such as the cross-coupled gate wires.

 

[keith1200rs]

It looks like a form of 'current starved' VCO (but I may be wrong).

Keith

 

[beixujia]

Thanks for your reply.

BradtheRad
------------------
there is three stage for the ring osc.
in the circuit, there are a V to I circuit and a ring osc buffer.
I mean, do you have experence use this V to I circuit ?
and do you have designed the ring osc ( invertor +cross couple) ?

 

[BradtheRad]

Sorry, I'm not very familiar with the topology.

I realize my simulation will not oscillate but it may portray how some concepts operate in your schematic.

https://tinyurl.com/bacq64e

If you click the above link it will open the falstad.com/circuit website, load my schematic, and run it on your computer. (Click Allow to load the Java applet.)

You can vary the 3 volt levels at will using the sliders at right.
You can alter values by right-clicking a component and choose Edit.

--------------------

Here are links to some threads that look as though they may be helpful.

https://www.edaboard.com/threads/139167/
(The above thread presents an attached schematic that resembles yours to an extent.)

https://www.edaboard.com/threads/146744/

https://www.edaboard.com/threads/245803/

https://www.edaboard.com/threads/35493/

 

[beixujia]

Hi, Dear BradtheRad:

I am so sorry give you wrong information.
Now I update it in attached file. My VCO is:

View attachment v.bmp
View attachment r.bmp

- - - Updated - - -

update again:
View attachment v.bmp

 

[BradtheRad]

Sorry, can't say much more. I have not worked with this type of circuit (ring oscillator).

From articles I see its behavior arises from propagation delay through the mosfets. That is why there is no need for capacitors, etc.