Crystal Oscillator Startup Control With Adaptive Noise Injection
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Solution Overview
Problem
Crystal oscillators require significant energy for startup, leading to prolonged startup times, especially in power-limited conditions, due to varying crystal resistance and inefficient noise injection methods.
Innovation Solution
A learning block is introduced to individually control noise injection during startup by counting clock cycles for stabilization, with an adjustment block to fine-tune based on crystal characteristics, and a negative capacitance circuit to cancel shunt resistance, optimizing startup time without frequency shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If high energy is injected at startup to reduce startup time, then startup time is reduced, but energy consumption increases significantly
Solution Approach 1:
The patent applies dynamics by making the negative resistance value variable rather than fixed. The control circuit dynamically adjusts the negative resistance based on real-time detection of oscillation amplitude and phase, allowing the system to use high negative resistance during startup to reduce startup time, then automatically reduce it during steady-state operation to minimize energy consumption.
Solution Approach 2:
The patent implements feedback through a control circuit that continuously monitors the oscillation signal's amplitude and phase, compares it with reference values, and automatically adjusts the negative resistance accordingly. This closed-loop feedback mechanism ensures the system transitions optimally from startup to steady-state operation, balancing startup speed and energy efficiency.
2Object-affected harmful factors
If power is decreased to achieve optimal noise performance in steady state, then noise performance improves, but startup time increases
Solution Approach 1:
The patent makes the negative resistance dynamic, allowing it to take different values during startup versus steady-state operation. During startup, high negative resistance enables fast oscillation build-up despite increased noise. During steady-state, the negative resistance is reduced to minimize noise while maintaining stable oscillation, thus achieving both fast startup and optimal noise performance at different phases.
Solution Approach 2:
The control circuit performs preliminary action by detecting oscillation startup and automatically adjusting the negative resistance before the system enters steady-state operation. This preliminary adjustment ensures the system is prepared for low-noise operation from the moment oscillation stabilizes, preventing noise degradation during the transition phase.
3Use of energy by moving object
If crystal resistance is decreased to reduce power consumption, then power consumption decreases, but startup capability is compromised
Solution Approach 1:
The patent dynamically controls the negative resistance provided by the active circuit based on oscillation detection. During startup when crystal resistance is naturally high, the control circuit maintains high negative resistance to ensure reliable oscillation initiation. Once oscillation is detected and stabilized, the negative resistance is reduced to match the lower crystal resistance in steady-state, minimizing power consumption while ensuring startup reliability.
Solution Approach 2:
The control circuit uses feedback from oscillation detection to automatically adjust the negative resistance. The detection circuit monitors whether oscillation has started, and based on this feedback, the control circuit switches the negative resistance from a high value (for reliable startup) to a low value (for minimal power consumption), ensuring both startup reliability and power efficiency.
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
This approach reduces startup time by dynamically adjusting noise injection based on crystal-specific characteristics, minimizing energy consumption and achieving faster stabilization, thus improving efficiency and power management.
Implementation Method 1
A crystal oscillator, particularly one made of quartz crystal, works by being distorted by an electric field when voltage is applied to an electrode near or on the crystal. This property is known as electrostriction or inverse piezoelectricity.
Implementation Method 2
When the field is removed, the quartz - which oscillates in a precise frequency - generates an electric field as it returns to its previous shape, and this can generate a voltage.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A learning block (200) can be placed in parallel to an oscillator circuit (100) to control noise injection during the startup of a crystal oscillator. The learning block (200) can be configured to control the noise injection during the startup of the crystal oscillator by determining whether the crystal oscillator has been stabilized. An adjustment block (300) may be employed to adjust the count determined by the learning block (200) based on one or more measured characteristics of the crystal oscillator during a startup of the crystal oscillator. A simple block that creates a negative capacitance can be configured in parallel to the crystal oscillator.