Oscillator Frequency Detection Using Clock Counts and Temperature Selection
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Solution Overview
Problem
Existing devices using external crystal oscillator circuitry for clock signals face challenges in accurately determining the frequency due to variations in resistor resistance with temperature, leading to inconsistencies in clock signal generation, particularly for devices requiring stable fixed frequencies with minimal phase noise.
Innovation Solution
A frequency detection circuitry that utilizes a high-speed oscillator signal and a temperature-dependent low-speed oscillator signal, coupled with comparator circuitry to determine frequency ranges and select the appropriate frequency based on temperature indications, ensuring accurate clock signal generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external crystal oscillator circuitry is used to generate clock signals, then frequency accuracy is improved, but temperature variations cause resistor resistance changes leading to frequency determination errors
Solution Approach 1:
The patent applies preliminary action by measuring the actual frequency of the oscillator signal before using it to generate clock signals. The frequency detection circuitry measures the oscillator signal frequency and stores this information in advance, so that the system can compensate for frequency variations when generating clock signals, thereby maintaining accuracy despite temperature changes.
Solution Approach 2:
The patent implements feedback by using the measured oscillator frequency information to adjust the clock signal generation process. The frequency detection circuitry continuously monitors the oscillator signal and feeds back frequency measurement data, which is then used to modify the operation of clock generation circuitry, ensuring stable and accurate clock signals despite environmental variations.
2Reliability
If temperature compensation is implemented to maintain frequency stability, then clock signal reliability is improved, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary frequency detection circuitry that acts as a mediator between the oscillator signal source and the clock generation circuitry. This intermediary component measures the oscillator frequency and provides compensation information, simplifying the overall temperature compensation approach while maintaining reliability.
Solution Approach 2:
The patent applies parameter changes by utilizing the measured frequency parameter to adjust clock signal generation. Instead of implementing complex physical temperature compensation mechanisms, the system changes operational parameters (frequency measurements and compensation values) to maintain stability, reducing hardware complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides precise frequency determination of the high-speed oscillator signal, reducing errors in clock signal generation and maintaining stability across varying temperatures, thereby enhancing the reliability of devices relying on these signals.
Implementation Method 1
variations in resistor resistance with temperature
Data Source
AI summary
An example apparatus includes: comparison circuitry configured to determine first and second frequencies from a plurality of clock count ranges and a clock count value, the plurality of clock count ranges each having a range of possible count values corresponding to possible frequencies, the first and second frequencies correspond to the clock count ranges that include the clock count value; comparator circuitry configured to generate a temperature indication based on a comparison of a temperature voltage to a reference temperature voltage; and overlap determination circuitry configured to select one of the first or second frequencies based on the comparator circuitry.