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Design >> Analog Design >> Delay locked loop -- reconfigurable phase selection
https://designers-guide.org/forum/YaBB.pl?num=1235558159

Message started by taofeng on Feb 25^th, 2009, 2:35am

Title: Delay locked loop -- reconfigurable phase selection
Post by taofeng on Feb 25^th, 2009, 2:35am

Hi all,

I hope I could have some real help from the DLL experts in this forum. Let me first describe my problem referring to the attached file.
Basically I want to make a Delay Locked Loop. However, the delay lines inside the loop are composed of (1-delta%) and delta% which give the total 100% delay (or 2*pi) phase shift. Then I want to make a tap selection from the part of the delta%.
The question is how to design this delay cell and how to further make the delta% reconfigurable, for instance I can easily change the percentage of delta (for instance from 5% to 20%).

thank you for your help !

Jef

Title: Re: Delay locked loop -- reconfigurable phase selection
Post by ywguo on Feb 25^th, 2009, 11:15pm

Hi Jef,

Assume the delay line 1-Δ% and Δ% contain 100 delay cells. The right most delay line in your schematic needs 20 delay cells, where one of the outputs is chosen using a multiplexor. Be careful to make the load of all the 120 delay cells balance.

Yawei