Semiconductor Clock Calibration Using Local PVT Ring Oscillators
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Solution Overview
Problem
Existing clock generation techniques in semiconductor circuits fail to optimize performance and reduce power consumption due to inadequate handling of process, voltage, and temperature (PVT) variations, leading to suboptimal clock signal margins that do not flexibly respond to environmental changes.
Innovation Solution
The implementation of a semiconductor device with multiple ring oscillators positioned near logic circuits to generate oscillating signals reflecting local and global PVT variations, a detecting circuit to generate a clock signal, and a calibration circuit to adjust the clock signal frequency based on these variations, ensuring optimal operation and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform clock signal margin is applied to the entire semiconductor circuit based on worst-case PVT variation, then timing errors are avoided, but performance and power consumption are not optimized
Solution Approach 1:
The semiconductor circuit is divided into multiple regions with different PVT characteristics, and each region is assigned a dedicated ring oscillator. This segmentation allows each clock signal to be optimized for its specific region rather than using a uniform worst-case margin across the entire circuit, thereby improving performance while maintaining timing reliability.
Solution Approach 2:
Each region receives a clock signal with margin characteristics tailored to its local PVT conditions. Regions with more severe PVT variation receive larger margins, while regions with stable characteristics receive smaller margins. This local quality approach optimizes performance in stable regions while ensuring reliability in variable regions.
2Reliability
If a uniform clock signal margin is applied to the entire semiconductor circuit based on worst-case PVT variation, then timing errors are avoided, but power consumption increases
Solution Approach 1:
The circuit is segmented into multiple regions, each with its own ring oscillator generating clock signals with appropriate margins for that region. This eliminates the need to apply maximum worst-case margins across the entire circuit, reducing overall power consumption while maintaining timing reliability in each specific region.
Solution Approach 2:
Each region receives a clock signal with margin characteristics matched to its local conditions. Regions experiencing severe PVT variation receive sufficient margins for reliability, while regions with stable characteristics receive minimal margins, thereby reducing total power consumption compared to a uniform high-margin approach.
3Productivity
If the clock signal frequency is set high to improve processing speed, then productivity increases, but timing errors occur under significant PVT variation
Solution Approach 1:
Different regions of the circuit receive clock signals with frequencies and margins customized to their local PVT characteristics. Regions with stable PVT can operate at higher frequencies for improved productivity, while regions with significant variation use lower frequencies with appropriate margins to avoid timing errors.
Solution Approach 2:
The clock signal parameters (frequency and margin) are dynamically adjusted based on the specific PVT conditions of each region. This dynamic approach allows the circuit to operate at optimal speeds while maintaining timing reliability under varying conditions, rather than using a static conservative setting across the entire circuit.
4Adaptability or versatility
If multiple ring oscillators are deployed at different locations to reflect local PVT variations, then clock signal optimization is improved, but device complexity increases
Solution Approach 1:
The circuit is divided into a reasonable number of regions, each with its own ring oscillator. This segmentation provides sufficient adaptability to capture local PVT variations without creating excessive complexity. The number and placement of ring oscillators are optimized to balance adaptability with device complexity.
Data Source
AI summary
Clock generation and control in a semiconductor system having process, voltage and temperature (PVT) variation. A semiconductor device may include at least first and second ring oscillators, each disposed at locations respectively closest to first and second logic circuits of an operation circuit, and generating first and second oscillating signals. A detecting circuit is configured to perform a predetermined logic operation on the first oscillating signal and the second oscillating signal to generate a first clock signal. A calibration circuit is configured to receive the first clock signal from the detecting circuit and perform a delay control on each of the first ring oscillator and the second ring oscillator to generate a second clock signal for operating the operation circuit.