Proactive IC Power Limit Protection via Frequency Scaling
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Solution Overview
Problem
High-performance system-on-a-chip (SoC) devices face limitations in power delivery networks, leading to potential battery stress and system shutdowns due to instantaneous power surges, which existing reactive power management techniques are unable to prevent effectively.
Innovation Solution
A proactive power management method that calculates the expected current for each domain of an integrated circuit before state transitions, comparing it to a power limit, and reducing domain frequencies if necessary to maintain instantaneous power within safe limits, thereby preventing excessive power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reactive power management techniques (PL2, PL3) are used to monitor and reduce power after limits are exceeded, then power consumption is reduced, but the response is too slow to prevent instantaneous power damage
Solution Approach 1:
The patent applies preliminary action by calculating the expected instantaneous power before state transitions occur. The power management unit computes the expected power based on requested frequency and voltage states, and compares it against the power limit in advance. If the expected power exceeds the limit, the frequency request is reduced before the transition happens, preventing the power surge rather than reacting to it afterward.
2Reliability
If domain frequencies are reduced to maintain power limits, then instantaneous power is kept below the limit, but system performance and productivity are degraded
Solution Approach 1:
The patent applies partial action by reducing the frequency only when necessary to comply with the power limit. The power management unit selectively reduces the frequency of specific domains that would cause the total instantaneous power to exceed the limit, rather than reducing all domains universally. This allows the system to maintain maximum performance when power limits are not violated and only applies frequency reduction as a partial corrective measure when needed.
3Reliability
If current per voltage regulator domain is calculated to enforce limits, then individual domain power is controlled, but this approach is not appropriate for multiple VR domains and causes undesirable performance reduction
Solution Approach 1:
The patent applies merging by calculating the total instantaneous power across all voltage regulator domains combined, rather than enforcing limits on each domain separately. The power management unit sums the power consumption of all domains and compares the aggregate against the power limit. This allows the system to optimize power distribution across domains while maintaining overall compliance, avoiding the performance penalties of strict per-domain limiting.
Data Source
AI summary
A method and apparatus for providing proactive current protection. In one embodiment, the method comprises: prior to transitioning to a new state for an integrated circuit (IC), calculating a sum of expected powers for a plurality of domains in the IC by calculating an expected current for each of the plurality of domains based on an individual domain frequency in the new state and multiplying the expected current with its associated voltage for each of the plurality of domains for the new state; comparing the sum to a power limit; and if the sum is greater than the power limit, then reducing the individual domain frequency associated with at least one domain in the plurality of domains to maintain the total instantaneous power of the IC below the power limit.