Dynamic Voltage Scaling for IC Power Management
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Solution Overview
Problem
Existing dynamic voltage and frequency scaling (DVFS) techniques face limitations in balancing power saving and performance, particularly in latency-sensitive applications, due to restricted voltage ranges and granularity of independent voltage control, which hinders optimal power efficiency and quality of service (QoS).
Innovation Solution
A method and apparatus that dynamically adjust the performance states of functional units, such as SRAM or CPU cores, by setting voltages to under-voltage or over-voltage margin settings based on activity data and system requirements, using a power management unit with state arbiter control logic to select corresponding performance margin profile state data, allowing for more granular control of power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional DVFS techniques use nominal voltage ranges determined by worst case assumptions, then reliability and yield requirements are met, but power consumption cannot be optimized further
Solution Approach 1:
The patent implements dynamic voltage scaling by introducing multiple performance states (P-states) with different voltage and frequency combinations. The system can dynamically transition between these states based on workload demands, allowing voltage to be reduced below nominal minimum when reliability constraints are not needed, thus optimizing power consumption while maintaining reliability when required.
Solution Approach 2:
The patent changes the voltage parameter by introducing under-voltage margin settings and over-voltage margin settings that extend beyond traditional nominal voltage ranges. By using voltage offset values applied to reference voltages, the system can operate at voltages lower than the nominal product minimum voltage, achieving further power optimization while using activity data to determine when such aggressive voltage scaling is acceptable.
2Use of energy by moving object
If voltage range for DVFS is extended beyond nominal product specifications, then power efficiency is improved, but voltage margin requirements for reliability may be violated
Solution Approach 1:
The patent employs feedback mechanisms by monitoring activity data (such as temperature, workload intensity, and operational patterns) to dynamically determine whether to apply under-voltage or over-voltage margin settings. This feedback loop ensures that voltage margin requirements are maintained when needed for reliability while allowing extended voltage ranges when power efficiency is the priority, thus resolving the contradiction between power efficiency and reliability.
3Adaptability or versatility
If fine-grained voltage islands or dual voltage rail SRAM arrays are used, then independent voltage control is achieved, but device complexity increases
Solution Approach 1:
The patent applies a universal voltage control mechanism that can be applied across different functional units without requiring separate voltage island infrastructure. The power management unit uses a unified approach with activity data monitoring and performance state transitions that works for various SRAM configurations and functional units, achieving independent voltage control benefits without the complexity of fine-grained voltage islands or dual voltage rail architectures.
Data Source
AI summary
A method and apparatus control power consumption of at least one functional unit on an integrated circuit by determining that a change in a first performance state is required for the at least one functional unit, and changing the first performance state to a second performance state that sets voltage for the functional unit to be at an under-voltage margin setting with respect to a nominal product minimum voltage of the functional unit.