What is replica bias and how does a delay cell work?

Hello members,

Could anyone explain how works electrically a delay cell. (Shematic fig 2)

Can someone tell me what is a Replica bias (Shematic fig 1). What it's role and

what it do ?

Thanks.

Bias

Hi,
I'm investiguating these circuit. I know that the delay cell is used for VCO design and The Replica is used in the design of Charge pump.

Bias

These cells are used in high speed digital design

Bias

Could anyone Help ?
I need also informations on.

Bias

Hmmm...the one on the left looks like an active cascode and the one on the right looks like an Opamp with active load...why is it called a delay cell??
Can anyone explain that clearly??

Re: Bias

The input ("Vin+" - "Vin-") to the differential pair are either in ECL logic or some form of logic signal, the input should be large enough to switch the differential pair.

I think the tail current (Mdiffbias) of the differential pair is two times the current in the MP1 and MP2. (based on the schematic is seem that there are some errors, the Id current in Mdiffbias is the same as the MP1 and MP2, mouzid please check this) .

Assuming Id current in MP1 is I and the capacitors seem in the Vout- and Vout+ nodes are the same, it is equal to Cds of MP1 + Cds of the differential + the cload of the next stage. The delay is controlled by the current I as output voltage swing will depends the current is need to charge the capacitance in the Vout- or vVout+ nodes.

To control the amount of current charging the capacitance in the output node, the Vcont voltage controls the bias current. Thus the delay can be controlled by Vcont voltage.

Increase the Vcont voltage will shorten the delay, similarly decrease the Vcont voltage will increase the delay.

Bias

The second one seems to be a differential circuit, I would suggest you to look at this link:
https://webcast.berkeley.edu/course_details.php?seriesid=1906978279 There are videos explaining such circuits, I think this link is very usefull