Ultra-Low Power PLL Timing Circuit for Temperature-Stable Clock Locking
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Solution Overview
Problem
Timing circuits, particularly those using crystal oscillators, are sensitive to temperature fluctuations, leading to frequency drift and timing errors in applications requiring high precision, such as telecommunications and GPS systems.
Innovation Solution
An ultra-low power timing circuit system incorporating a receiver circuit, phase lock loop (PLL) circuit, crystal oscillator (XO) circuit, temperature sensing and calibration circuit, and temperature compensation circuit, which work together to stabilize the frequency of the output clock signal by sensing temperature and adjusting the XO circuit accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If crystal oscillators are used in timing circuits, then timing precision is improved, but temperature sensitivity causes frequency drift and timing errors
Solution Approach 1:
The patent implements a feedback mechanism where the output of the crystal oscillator is fed into a phase-locked loop (PLL) that compares it with a reference clock signal. The PLL generates a control signal that adjusts the oscillator's frequency to maintain locking, thereby compensating for temperature-induced frequency drift and maintaining timing precision.
Solution Approach 2:
The patent changes the operating parameters of the crystal oscillator by using a PLL to dynamically adjust the frequency control voltage. This allows the oscillator to adapt its frequency parameter in response to temperature variations, counteracting the harmful effects of temperature sensitivity while preserving timing precision.
2Stability of the object's composition
If temperature compensation circuits are added to stabilize frequency, then timing stability is improved, but power consumption increases
Solution Approach 1:
The patent employs a self-service approach where the phase-locked loop automatically adjusts the crystal oscillator's frequency without requiring external intervention or complex temperature sensing circuits. The PLL uses the reference clock and the oscillator's own output to generate the necessary control signals, achieving frequency stability with minimal additional power consumption.
Solution Approach 2:
The phase-locked loop serves multiple functions simultaneously: it acts as a frequency stabilizer, a temperature compensator, and a reference clock generator. This multi-functionality reduces the need for separate dedicated circuits, thereby limiting the increase in power consumption while achieving frequency stability.
3Reliability
If phase lock loop circuit is used to lock frequency, then clock synchronization is improved, but circuit complexity increases
Solution Approach 1:
The patent merges the temperature compensation function with the phase-locked loop operation. The PLL's control signal simultaneously performs frequency locking and temperature compensation, eliminating the need for separate compensation circuits and reducing overall system complexity while maintaining reliable clock synchronization.
Solution Approach 2:
The phase-locked loop acts as an intermediary between the reference clock and the crystal oscillator, mediating the frequency relationship and providing automatic adjustment. This intermediary function simplifies the overall system architecture compared to using separate independent circuits for frequency control and temperature compensation.
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 achieves precise clock synchronization and stability across varying temperatures, improving performance in GPS-denied environments and reducing power consumption.
Implementation Method 1
The temperature sensing and calibration circuit is configured to sense the operating temperature and to calibrate the XO circuit based on the operating temperature, the control signal, and the compensation signal
Implementation Method 2
The phase frequency detector may be configured to compare the reference clock signal and the output clock signal. The phase frequency detector may be configured to produce the control signal based on the comparison of the reference clock signal and the output clock signal
Implementation Method 3
The temperature compensation circuit is configured to produce a compensation signal based on an operating temperature, and to provide the compensation signal to the temperature sensing and calibration circuit
Data Source
AI summary
Methods, systems, and computer program products are presented herein for circuit timing using ultra-low power (ULP) timing circuit systems. A ULP timing circuit system comprises a receiver circuit, phase lock loop (PLL) circuit, crystal oscillator (XO) circuit, temperature sensing and calibration circuit, and temperature compensation circuit. The receiver circuit is configured to receive a reference clock signal. The XO circuit is configured to produce an output clock signal. The PLL circuit is configured to produce a control signal based on the reference clock signal and output clock signal. The temperature compensation circuit is configured to produce a compensation signal based on an operating temperature. The temperature sensing and calibration circuit is configured to sense the operating temperature and to calibrate the XO circuit based on the operating temperature, control signal, and compensation signal to lock a frequency of the output clock signal to the reference clock signal.