I want to design some some adjustable components for the circuit so that the speed of the whole circuit could be controlled. I knew the following design skills:

1. Adjust the power voltage.
2. Insert/Delete some capacitors on the interconnect lines.

Anyone knows other design methods? Such as change the substrate voltage of the transistor? Is this a good option since I am not sure if people can chage individual transistor's substrate voltage on the die.


Thanks in advance.

Actually, I am trying to adjust the delay of the longest or the critical path in the logic circuit. Basicly, since the process variation is not controllable in most cases, if we can make the gate delay or the interconnect delay tunable or adjustable from outside, we can use the test patterns to test and adjust the delay of the circuit, this will give us a chance to erase the effects of the process variation.

transistor sizing is a possible way to do that, but I guess it will require too much space if we want to make all the gate sizes adjustable.

I am trying to use the adjustable power distribution or tunable capacitors to do the trick, but not effective enough, actually. Any better ideas?

That is Cool!!!

Can you provide any of your publications or references so that I can look at your previous work? If you can drop a message to me, I will really appreicate your help.

Thanks.


[quote author=Andrew Beckett  link=1117422002/0#3 date=1118603976]One way I've done this in the past (in a delay locked loop) is to use a simple voltage regulator to control the supply to the inverter chain in the delay locked loop - adjusting the supply to the inverter chain such that one cycle of the incoming clock matches the whole inverter chain.

Regards,

Andrew.
[/quote]

I'd also suggested (in an off-line message) that CDROM just did some searching on google to find a number of papers on such things.

Regards,

Andrew.