PVT-Compensated Delay Timing for Stable On-Chip Reference Signals
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Solution Overview
Problem
Miniaturized ICs face challenges in generating stable reference signals due to ambient PVT variations, as external quartz crystals are unsuitable for miniaturization and micro-electromechanical or analog circuits are influenced by environmental changes, leading to output frequency variations.
Innovation Solution
An absolute time delay generating device is developed, comprising a PVT detection device with signal phase/frequency control modules and delay modules, which compare delay statuses to generate correction signals and adjust oscillation signals using a digital control oscillator, eliminating the need for external quartz crystals and stabilizing reference signals against PVT variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external quartz crystal is used as signal generating terminal, then stable reference signal is generated, but device size cannot be miniaturized
Solution Approach 1:
The patent extracts the frequency reference function from the external quartz crystal and implements it within the IC using a ring oscillator with PVT compensation. The delay modules extract delay characteristics from signal propagation through different circuit paths, and the phase/frequency detector extracts frequency error information to generate correction signals, thereby eliminating the need for external quartz crystal while maintaining frequency stability.
Solution Approach 2:
The patent introduces delay modules as intermediary elements that compare signal propagation delays through different paths (control unit vs reference unit). This intermediary delay comparison mechanism enables PVT variation detection without requiring external reference components, serving as a mediator between the oscillator and the frequency stabilization function.
2Volume of moving object
If micro-electromechanical or analog circuit is used to generate reference signals, then device is miniaturized, but output frequency varies with PVT environment
Solution Approach 1:
The patent implements a feedback mechanism where the phase/frequency detector continuously monitors the frequency output of the ring oscillator and generates correction signals based on detected frequency errors. These correction signals are fed back to the delay modules to adjust the oscillator frequency, forming a closed-loop system that compensates for PVT variations and maintains stable output frequency in miniaturized ICs.
Solution Approach 2:
The patent makes the delay characteristics of the control unit dynamic by adjusting delay element parameters based on detected PVT conditions. The delay modules dynamically adapt their delay properties to compensate for environmental variations, transforming the static analog circuit into a dynamically adjustable system that maintains frequency stability despite PVT changes.
3Measurement precision
If delay modules with different delay properties are used, then PVT detection capability is improved, but device complexity increases
Solution Approach 1:
The patent segments the frequency stabilization function into multiple independent delay modules, each with different delay properties. These segmented modules compare delay statuses through different circuit paths, enabling precise PVT detection. The segmentation allows parallel operation of multiple delay comparison channels, improving measurement precision while keeping each individual module relatively simple in structure.
Data Source
AI summary
An absolute time delay generating device includes a PVT (process-voltage-temperature) detection device and a delay-timing generator. The PVT detection device includes at least a delay module and a signal phase/frequency control module. The delay module includes a control unit and a reference unit. The control unit differs from the reference unit in sensitivity of delay property to PVT. The delay module compares phase or frequency differences generated when origin signals pass through the control unit and reference unit respectively, and produce delay parameters of the delay module. The signal phase/frequency control module receives and compares the delay parameters to determine an ambient PVT condition for the absolute time delay generating device, so as to control and correct the delay-timing generator and thereby generate accurate absolute time delay. Under various PVT influences, the absolute time delay generating device is capable of generating accurate, absolute time signals.