Adaptive Clock Generation Using Delay Feedback to Cut Timing Margin
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Solution Overview
Problem
Synchronous digital circuits face performance losses due to variability in delay variations caused by manufacturing processes, environmental conditions, and voltage fluctuations, leading to suboptimal clock signal frequencies that result in performance margin, even when worst-case scenarios are not present.
Innovation Solution
Adaptive clock generators that dynamically adjust the frequency of the clock signal based on selected delay paths within the circuit, using delay circuits and feedback loops to ensure optimal performance without exceeding maximum frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the frequency of the clock signal is set to the maximum performance rate of the circuit, then the performance of the circuit is maximized, but the circuit may not operate properly when delay variations occur due to manufacturing variability, environmental conditions, or voltage fluctuations
Solution Approach 1:
The patent implements a dynamic clock frequency adjustment mechanism that continuously monitors delay variations in the circuit and adapts the clock signal frequency in real-time. The system transitions from a static fixed-frequency approach to a dynamic adaptive approach, where the clock generator modifies the frequency based on actual circuit performance conditions, thereby maximizing productivity while ensuring reliability under varying operating conditions
Solution Approach 2:
The patent employs a feedback mechanism where delay measurements from the circuit are fed back to the clock generator. The system measures actual delay variations caused by manufacturing variability, temperature, and voltage fluctuations, then uses this feedback information to adjust the clock frequency accordingly. This closed-loop feedback system enables the circuit to maintain proper operation while operating at optimal performance levels
2Reliability
If the maximum frequency of the clock signal is lowered to account for worst case delay variations, then proper circuit operation is ensured under all conditions, but the frequency margin creates performance margin even when worst case delay conditions are not present, lowering overall circuit performance
Solution Approach 1:
The system dynamically adjusts the clock frequency based on actual delay conditions rather than using a static worst-case frequency. When delay variations are within acceptable ranges, the clock frequency operates at higher performance levels. Only when actual delay variations approach worst-case scenarios does the system lower the frequency to maintain proper operation, thereby eliminating unnecessary performance margins during normal operation
Solution Approach 2:
The patent changes the operating parameters of the clock signal (frequency) based on measured delay conditions. Instead of fixed parameter settings, the system continuously monitors delay parameters and adjusts the clock frequency parameter in response to actual circuit behavior, allowing optimal performance under normal conditions while maintaining reliability when delay variations occur
Data Source
AI summary
Adaptive clock generators, systems, and related methods than can be used to generate a clock signal for a functional circuit to avoid or reduce performance margin are disclosed. In certain embodiments, a clock generator autonomously and adaptively generates a clock signal according to a delay path(s) provided in a delay circuit(s) relating to a selected delay path(s) in the functional circuit(s). The clock generator includes a delay circuit(s) adapted to receive an input signal and delay the input signal by an amount relating to a delay path(s) of a functional circuit(s) to produce an output signal. A feedback circuit is coupled to the delay circuit(s) and responsive to the output signal, wherein the feedback circuit is adapted to generate the input signal back to the delay circuit(s) in an oscillation loop configuration. The input signal can be used to provide a clock signal to the functional circuit(s).