PVT-Adaptive Clock Control Using Distributed Ring Oscillators
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Solution Overview
Problem
Existing clock generation and control methods 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 performance and increased power consumption.
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 conditions, a detecting circuit to generate a clock signal, and a calibration circuit to adjust the clock signal frequency based on these conditions, 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 patent divides the semiconductor circuit into multiple regions with different PVT characteristics and applies locally-optimized clock margins to each region. Ring oscillators are distributed throughout the circuit to sense local conditions, and clock signals are adjusted per-region rather than using a single uniform margin for the entire circuit. This allows each region to operate at optimal performance while maintaining timing accuracy.
Solution Approach 2:
The patent implements dynamic clock frequency adjustment based on real-time PVT monitoring. Ring oscillators continuously sense local temperature, voltage, and process variations, and the clock signal frequency is dynamically modified in response to these changing conditions. This replaces static worst-case margins with adaptive, condition-dependent clocking that optimizes performance as conditions vary.
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 patent applies localized clock margin adjustments only where needed based on actual PVT conditions in each region. Instead of applying a conservative uniform margin across the entire circuit that increases overall power consumption, the system identifies specific regions requiring timing protection and applies margin adjustments only to those areas, reducing unnecessary power dissipation in regions that do not require such protection.
Solution Approach 2:
The patent dynamically changes clock signal parameters (frequency, margin) based on monitored PVT conditions. When conditions are favorable, the system reduces clock margins and increases frequency to minimize power consumption. When PVT variations approach critical thresholds, the system adjusts parameters to maintain timing accuracy. This adaptive parameter modification eliminates the need for consistently high power consumption required by fixed worst-case margins.
3Productivity
If the clock signal frequency is set high to maximize processing speed, then productivity improves, but timing errors occur under significant PVT variation
Solution Approach 1:
The patent implements feedback loops where ring oscillators continuously monitor local PVT conditions and feed this information back to clock control logic. Based on this feedback, the system dynamically adjusts clock frequency and margin to maintain optimal operation. When PVT conditions deteriorate, the feedback mechanism automatically reduces frequency or increases margin to prevent timing errors, allowing the system to operate at high speeds under good conditions while maintaining reliability when conditions worsen.
Solution Approach 2:
The patent replaces static clock frequency settings with dynamic adjustment mechanisms that adapt to changing PVT conditions. The system can operate at high frequencies when process, voltage, and temperature conditions are favorable, and automatically adjusts downward when conditions approach timing violation thresholds. This dynamic behavior enables maximum productivity under optimal conditions while preventing timing errors through real-time adaptation.
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.