Ring Oscillator Circuits for Precise Flip-Flop Clock-to-Q Timing
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Solution Overview
Problem
Existing flip-flop circuits lack precision in estimating the clock-to-Q propagation delay, leading to potential malfunctions in synchronous systems.
Innovation Solution
A ring oscillator circuit with a control circuit and multiplexer system that measures and adjusts clock-to-Q delay by injecting opposite clock edges and utilizing calibration modes to accurately determine clock-to-Q propagation delay across various flip-flop types, enabling precise timing adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional flip-flop circuits are used without specialized measurement structures, then device complexity is reduced, but measurement precision of clock-to-Q propagation delay deteriorates
Solution Approach 1:
The measurement function is segmented from the functional flip-flop paths. Dedicated measurement flip-flops are inserted at specific locations in the ring oscillator, separating the timing measurement function from the normal data processing paths. This allows precise measurement without affecting the complexity of functional circuits.
Solution Approach 2:
Ring oscillators serve as intermediary structures that enable indirect measurement of clock-to-Q propagation delay. Instead of directly measuring the delay, the patent uses ring oscillators to convert timing characteristics into frequency measurements, which can be precisely captured and converted to delay values.
2Measurement precision
If ring oscillator-based measurement circuits are implemented, then measurement precision of timing characteristics is improved, but device complexity increases
Solution Approach 1:
The ring oscillator structure serves multiple functions: it acts as both a measurement medium for timing characteristics and as a functional circuit element. The same ring oscillator infrastructure is used to measure different timing parameters (clock-to-Q, setup time, hold time) across multiple flip-flops, reducing overall system complexity through shared measurement resources.
Solution Approach 2:
The measurement flip-flops are merged into the functional flip-flop banks, and the ring oscillator measurement paths are combined with the functional data paths. This integration allows the measurement infrastructure to serve dual purposes, reducing the need for separate dedicated measurement circuits.
3Measurement precision
If calibration modes are added to the control circuit, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The control circuit is designed with dynamic configurability, allowing it to switch between different measurement modes (clock-to-Q measurement mode, setup time measurement mode, hold time measurement mode) and calibration modes. This dynamic behavior enables a single control circuit to perform multiple measurement functions, reducing the need for separate dedicated circuits for each measurement type.
4Adaptability or versatility
If multiple measurement modes are implemented in a single control circuit, then adaptability is improved, but device complexity increases
Solution Approach 1:
The control circuit is designed as a universal measurement controller that can handle multiple measurement types (clock-to-Q, setup time, hold time) and calibration operations through a single unified interface. This multi-functional design reduces the need for separate control circuits for each measurement type, thereby managing complexity while maintaining versatility.
Data Source
AI summary
A ring oscillator circuit with a frequency that is sensitive to the timing of a clock-to-Q (clk2Q) propagation delay of one or more flip-flops utilized in the ring oscillator. The clock2Q is the delay between the clock signal arriving at the clock pin on the flop and the Q output reflecting the state of the input data signal to the flop. Clk2q delay measurements are made based on measurement of the ring oscillator frequency, leading to more accurate estimates of clk2Q for different types of flip-flops and flip-flop combinations, which may in turn enable improvements in circuit layouts, performance, and area.