Ring Oscillator Current Sensing for Distributed Power Gating
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Solution Overview
Problem
Integrated circuits (ICs) face challenges in managing power consumption, as excessive load currents can lead to damage or malfunction, and existing current sensing circuits may not effectively control distributed load currents across multiple cores.
Innovation Solution
The apparatus and method employ a power gating circuit with current sensors using ring oscillators and frequency-to-code converters to generate digital signals indicative of load currents, allowing a controller to manage and reduce harmful currents across multiple cores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current sensing circuit is used to sense load current, then the load current can be detected to prevent damage, but the sensing circuit may not effectively control distributed load currents across multiple cores
Solution Approach 1:
The patent divides the current sensing function into multiple independent ring oscillator circuits, with each oscillator dedicated to sensing the load current of a specific core. This segmentation allows each sensing circuit to independently monitor its associated core's current, enabling effective distributed load current control across multiple cores while maintaining high detection accuracy for each individual core.
2Use of energy by moving object
If the clock frequency is reduced to lower load current, then power consumption is reduced, but the IC performance deteriorates
Solution Approach 1:
The patent applies local quality by enabling independent power gating control for each core through dedicated ring oscillator sensing circuits. This allows the power management system to selectively reduce power to only those specific cores that are exceeding current thresholds, rather than reducing clock frequency and power across the entire IC. Consequently, power consumption is reduced locally at the problematic core while other cores continue to operate at full performance.
Solution Approach 2:
The patent implements a feedback mechanism where each ring oscillator senses the load current of its associated core and provides real-time current information to the power gating circuit. This feedback loop enables dynamic, core-specific power adjustment - when a core's current exceeds the threshold, the power gating circuit selectively reduces power to that specific core while maintaining full power to other cores, thus reducing overall power consumption without degrading the performance of healthy cores.
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 solution enables precise control of load currents, preventing damage or malfunction by effectively sensing and managing distributed load currents, ensuring safe operation of ICs.
Implementation Method 1
a first ring oscillator including: a first set of one or more inverters coupled to a first node between the power gating circuit and the first circuit, and a second set of one or more inverters coupled to a second node between the power gating circuit and the second circuit
Data Source
AI summary
An apparatus for sensing distributed load currents provided by power gating circuit. The apparatus includes a power gating circuit including a set of bulk transistors coupled in series with a set of circuits between first and second voltage rails. The apparatus includes a current sensor with a first ring oscillator, a first frequency-to-code (FTC) converter, a second ring oscillator, a second FTC converter, and a subtractor. The first ring oscillator includes a first set of one or more inverters configured to receive a first voltage at a node between the power gating circuit and the first circuit, and a second set of one or more inverters configured to receive a second voltage at a second node between the power gating circuit and the second circuit. The first ring oscillator is configured to generate a signal including a frequency related to the voltage drops across the first and second sets of transistors.