Adaptive Voltage Shutdown Demotion for Power Optimization
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Solution Overview
Problem
Computing systems face inefficiencies in power management when transitioning between active and idle states, as powering down and up devices can consume significant energy due to inrush currents, often negating the power savings and increasing overall energy consumption.
Innovation Solution
An adaptive power control unit determines an optimum demotion threshold for powering down voltage rails based on system conditions, including device leakage current, workload, and capacitance, to optimize energy usage and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the voltage rail is powered down to a device during idle states, then power consumption is reduced, but powering back up causes power spikes due to inrush current which may negate the power savings
Solution Approach 1:
The system performs preliminary action by keeping the voltage rail powered up during short idle periods before the power savings would exceed the cost of power spikes. The adaptive demotion threshold determines when to switch from keeping power on to powering down, based on predicted idle duration. This preliminary keeping-of-power avoids the harmful inrush current spike for frequent or short idle transitions.
Solution Approach 2:
The system dynamically adjusts the demotion threshold based on changing system conditions including device leakage current, workload patterns, and capacitance values. The power control unit continuously monitors these parameters and adapts the threshold accordingly, transitioning between keeping power on and powering down based on real-time conditions. This dynamic approach optimizes the balance between avoiding power spikes and achieving power savings.
2Power
If the voltage rail is kept powered up to a device during idle states, then power spikes are avoided, but continuous power consumption increases overall energy usage
Solution Approach 1:
The system changes the operational parameters by dynamically adjusting the demotion threshold based on device leakage current, workload, and capacitance. When leakage current is high or idle periods are predicted to be long, the threshold is adjusted to power down the rail. When leakage is low or idle periods are short, the threshold keeps the rail powered up. This parameter adaptation optimizes the trade-off between power stability and energy consumption.
Solution Approach 2:
The power control unit implements feedback by continuously monitoring device leakage current, workload patterns, and capacitance values to determine the optimal demotion threshold. The system uses this feedback to adaptively adjust when to power down the voltage rail, ensuring that power is only cut when it will result in net energy savings rather than increased consumption from frequent power cycling.
3Productivity
If frequent cycling between active and idle states occurs with power down, then device can enter low power mode often, but the cumulative power from repeated inrush currents exceeds savings
Solution Approach 1:
The adaptive demotion threshold acts as an intermediary decision-making parameter that mediates between the desire to utilize idle states for power savings and the reality of cumulative inrush current costs. The threshold incorporates system-specific parameters (leakage current, capacitance, workload) to determine the optimal point at which power down becomes beneficial, preventing frequent cycling when it would be counterproductive.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach dynamically manages power consumption by determining when it is more energy-efficient to keep devices powered up or down, improving battery life and user experience by minimizing energy waste during idle states.
Implementation Method 1
a voltage regulator coupled to the device to supply a voltage level to the device when the device is idle
Implementation Method 2
the second energy cost is a second amount of energy for the voltage regulator to change the voltage level to the shutdown level
Data Source
AI summary
Embodiments described herein may include apparatus, systems, techniques, and/or processes that are directed to adaptively determining an optimum time frame or demotion threshold for when to power down a voltage rail of an idle device. The demotion threshold is typically the point where the energy cost for maintaining power to the device is approximately the same as or exceeds the energy cost of removing power to the device. The demotion threshold may vary with system conditions and may be based on device leakage current, wake voltage, capacitance, voltage regulator power consumption, current workload and the like. A power control unit in the computing system may manage the voltage of the device and determine the optimum demotion threshold. The power control unit may rely on physical inputs such as fuses on a motherboard, system inputs supplied by a manufacturer, current condition inputs and may be implemented in the device's or the system's software or firmware. By calculating the adaptive demotion threshold, power may be optimized based on platform-to-platform design variation and/or device part-to-part variation.