Integrated Reference Resonator Clock With Temperature Compensation
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Solution Overview
Problem
Existing clock generators, such as crystal oscillators, cannot be integrated with microprocessors as a single IC, leading to increased power consumption, space requirements, and manufacturing costs, and are not sufficiently accurate over PVT variations, resulting in the need for a highly accurate, integrated clock generator with minimal frequency drift and jitter.
Innovation Solution
A reference signal generator system that integrates a reference resonator with switchable circuits to maintain a stable resonant frequency over temperature variations, using calibrated resistances and reactances to offset temperature dependencies, allowing for accurate frequency control and low jitter operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If crystal oscillators are used to generate accurate clock signals, then frequency accuracy is improved, but integration with microprocessors is prevented
Solution Approach 1:
The patent merges the clock generator functionality with the microprocessor onto a single integrated circuit chip. This is achieved by integrating a resonator, amplifier, and frequency control circuitry directly with the microprocessor core, eliminating the need for separate crystal oscillator components while maintaining frequency accuracy through on-chip temperature compensation mechanisms.
2Reliability
If separate clock ICs are used to maintain frequency accuracy, then frequency stability is improved, but power consumption increases
Solution Approach 1:
By integrating the clock generator with the microprocessor, the patent eliminates the need for separate clock ICs. The shared power supply and ground structures, along with integrated temperature compensation circuitry, reduce overall power consumption while maintaining frequency stability through coordinated control of the resonator and amplifier stages.
Solution Approach 2:
The integrated clock generator uses the microprocessor's own temperature sensors and control logic to compensate for frequency drift, allowing the system to self-regulate frequency stability without requiring additional external temperature compensation circuits or separate control ICs.
3Measurement precision
If separate clock ICs are used to ensure accuracy, then frequency precision is improved, but device area increases
Solution Approach 1:
The patent consolidates the clock generator, resonator, amplifier, and temperature compensation circuitry onto the same silicon die as the microprocessor. This integration dramatically reduces the total device area by eliminating the need for separate clock ICs and their associated mounting space, trace routing, and mechanical connectors on the PCB.
4Ease of manufacture
If ring or relaxation oscillators are used for integration, then ease of manufacture is improved, but frequency accuracy deteriorates
Solution Approach 1:
The patent employs a resonator with dynamically adjustable parameters, including variable capacitance and inductance elements that can be tuned during fabrication and operation. This allows the oscillator frequency to be precisely calibrated to compensate for process variations, achieving high frequency accuracy while maintaining standard integrated circuit fabrication processes.
Solution Approach 2:
The design incorporates temperature-compensated resonator parameters and bias voltages that are adjusted based on operating conditions. By dynamically changing the resonant frequency parameters in response to temperature and process variations, the system maintains high frequency accuracy despite using standard integrated circuit manufacturing techniques.
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 system provides a highly accurate, low-jitter clock signal that is integrated with other circuitry, reducing power consumption and space requirements while maintaining stability over PVT variations, making it suitable for precise applications.
Implementation Method 1
crystal oscillators, such as quartz oscillators, which provide a mechanical, resonant vibration at a particular frequency
Implementation Method 2
switchable circuits are utilized to provide a substantially stable resonant or center frequency f0, within a predetermined variance, over variations in operating (and/or ambient) temperature
Data Source
AI summary
Exemplary embodiments provide a reference signal generator having a reference or center frequency within a predetermined variance over variations in temperature within a specified range. An exemplary apparatus comprises a reference resonator to generate a first reference signal having a resonant frequency, with the reference resonator having a first temperature dependence; and a plurality of switchable circuits, with at least one switchable circuit providing a second temperature dependence opposing the first temperature dependence to maintain the resonant frequency within a predetermined variance over a temperature variation. A wide variety of switchable circuits are disclosed, including a transistor having an on resistance value greater than a nominal resistance, a resistor coupled to a transistor or other switch, and circuit comprising a first reactance coupled to a first switch, with a second reactance coupled to a resistance and a second switch coupled in series to the second reactance or to the resistance. Various coatings may also be applied to an integrated circuit embodiment, such as a silicone coating on a first surface and a metal layer on a second surface.