Can we play with Supply voltage to fix the Hold Violation?

[kumar_eee]

People normally add the Delay before the 'D' pin of the flipflop to remove the Hold violation. Can we do something with the supply voltage to fix the hold violation?

 

[venky4u]

I don't think we can change the supply voltage( reduce supply voltage) to fix the hold violations, as it affects the total design, which may result in setup violations other points.

 

[yx.yang]

I don't think we can change the supply voltage( reduce supply voltage) to fix the hold violations, as it affects the total design, which may result in setup violations other points.

And another question about the sugestion: if your chip has manufacturated, you can try it. While if it's still under developing, do you have the cell library with the voltage you want to IC is running at?

 

[phoenixpavan]

Hi Kumar,

It will be of less feasibility as you the increase in delay will not be sufficient I guess...Jst guessing

 

[venky4u]

@yx.yang..
yes, we can try it if the chip is manufactured, but at lower frequency, as i feel it will definitely cause setup violations. so to make the chip work at different voltage without setup violations we need to operate at low frequencies.
as you suggested we need library with the voltage we want to chip to run.

@kumar,
i hope your doubts are cleared.

---------- Post added at 18:17 ---------- Previous post was at 18:10 ----------

@pavan,
if the hold violation is huge, change in voltage will not be sufficient, as change in voltage will not result in drastic variation in delay values.

 

[kumar_eee]

Hi All,
Thanks a lot for the points. According to me, if we change the voltage, the chip may not work as expected, because the total delay will get changed. This is with respect to the chip having a single supply voltage.

Can we play around with the voltage using the concept called "Dynamic Voltage Frequency Scaling"?

Rgds,
Kumar

 

[haykp]

If your chip is manufactured, then you cannot use the "Dynamic Voltage Frequency Scaling" concept, because for that concept you need to have a separate control block.
The idea of "Dynamic Voltage Frequency Scaling" ( dfvs) is to decease the block supply voltage depending on block load to save the power. This technique is not prepare for changing the whole chip supply voltage instead it changes the chip separate blocks supply voltages. To implement the dfvs a separate block is being added which analysis the voltage scaled blocks working load and based on that load it scales the block supply voltage.