What is the "worst-case power corner" used for power signoff?
From PDVerse Low-Power Physical Design Mentor Guide · pdVerse Mentor Guide
Definition
The worst-case power corner is the PVT (process, voltage, temperature) combination defined as fast process, maximum voltage, and maximum temperature — the combination that produces the highest leakage and dynamic power a design could realistically see.
Mentor Explanation
The important point is that this is the opposite of the worst-case timing corner (which uses slow process, minimum voltage). A beginner often assumes there's one universal 'worst corner' for everything, but power and timing pull in opposite directions on process and voltage, so a design must be verified separately at each.
Example
In practice, a device signed off for power is evaluated at fast process + max voltage + max temperature — this matches the observation that the fast corner is the one that 'barely meets the [power] spec.'
Why It Matters
Signing off power only at this corner guarantees the design won't exceed its power budget on the fastest, hottest, highest-voltage parts that will ship — protecting against thermal and battery-life failures in the field.
Common Beginner Mistake
Beginners sometimes reuse the timing signoff corner set for power estimation, which produces an artificially low, unsafe power number since slow/low-voltage conditions minimize both leakage and dynamic power.
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