Multi-Point Calibration for Adaptive Voltage Scaling
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Solution Overview
Problem
Prior adaptive voltage scaling systems rely on single point calibration, which fails to account for measurement errors and transient supply voltage responses across multiple operating points, leading to inefficiencies in power management.
Innovation Solution
Implementing a multi-point calibration method with a plurality of Reference Calibration Codes in a Multi-Point Calibration Table, each optimized for specific clock frequencies, allowing for closed-loop control of digital processor delay margins and accurate voltage adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single point calibration is used in adaptive voltage scaling systems, then the system structure remains simple, but measurement errors and transient supply voltage responses across multiple operating points are not accounted for, leading to inefficiencies in power management
Solution Approach 1:
The patent divides the calibration system into multiple independent calibration points, each with its own reference calibration code stored in the multi-point calibration table. This segmentation allows the system to account for measurement errors and transient responses at each specific operating point independently, improving overall calibration accuracy without requiring a completely complex redesign of the entire calibration architecture.
Solution Approach 2:
The patent performs preliminary calibration at multiple operating points before normal operation. The multi-point calibration table is pre-filled with reference calibration codes obtained through preliminary measurements and computations. This preliminary action ensures that the system has accurate calibration data ready for use, avoiding the need for complex real-time calibration during operation.
2Productivity
If multiple reference calibration codes are stored for different clock frequencies, then power management efficiency improves, but the calibration table size and data storage requirements increase
Solution Approach 1:
The patent applies local quality by providing different reference calibration codes tailored to specific clock frequencies and operating conditions. Each entry in the multi-point calibration table contains calibration data optimized for its specific operating point, allowing the system to select the most appropriate calibration code for the current condition rather than using a single universal calibration value.
Solution Approach 2:
The patent implements partial action by storing reference calibration codes only for the specific clock frequencies and operating points that are actually used by the system, rather than attempting to cover all possible operating conditions. This selective approach improves power management efficiency for the relevant operating ranges while keeping the calibration data volume manageable.
3Reliability
If closed loop feedback is used to adjust supply voltage, then adaptive voltage scaling is achieved, but system delay increases due to the feedback loop
Solution Approach 1:
The patent performs preliminary computation of the required voltage adjustment and delay compensation before the actual voltage change occurs. The multi-point calibration table contains pre-computed reference calibration codes that account for expected transient responses and delays. This preliminary action allows the system to anticipate and compensate for feedback loop delays rather than reacting to them after they occur.
Solution Approach 2:
The patent implements feedback by using the Hardware Performance Monitor to continuously monitor actual processor delay and comparing it against expected values. The Advanced Power Controller uses this feedback information to select appropriate reference calibration codes from the multi-point calibration table, dynamically adjusting the supply voltage to maintain optimal performance while minimizing delay effects.
Data Source
AI summary
A system and method is disclosed for providing multi-point calibration of an adaptive voltage scaling (AVS) system. A plurality of Reference Calibration Codes (RCCs) within a multi-point calibration table is provided. Each code is associated with one of the clock frequencies of the adaptive voltage scaling (AVS) system. The present invention provides multi-point calibration by calibrating a Reference Calibration Code (RCC) for each operating point (clock frequency) of the adaptive voltage scaling (AVS) system.