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AR# 62437

2014.3 Vivado Power - Does 'set_switching_activity -signal_rate' impact the glitch power analysis?


Does 'set_switching_activity -signal_rate' impact the glitch power analysis?


Yes, the signal_rate option impacts the glitch analysis. 

------- Probability Equation------

 In ideal conditions, the toggle rate on an RTL node should meet this criterion:     

(RTL_toggle_rate/200) =< static_probability =< 1-(RTL_toggle_rate/200)

If the given switching rate does not satisfy this equation, then it is treated as glitch data.


You can extract RTL toggle rate using the following:  


For example: 

For freq 100MHz

set_switching_activity -static_probability 0.7 -signal_rate 150 [get_ports d]

Given Toggle Rate = 150/100 = 1.5  = 150%      - this given toggle Rate violates the above equation: 0.75  <= 0.7  <= 0.25

We need to extract the glitch component:

RTL Toggle Rate = 2*0.7(1-0.7) = 0.42   -> 42%

Therefore Glitch rate = 1.5 0.42 = 1.08

Once the glitch rate is identified, the glitch power analysis would be included in the general power analysis.

AR# 62437
Date 10/14/2014
Status Active
Type General Article
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