Crystal Oscillator Dynamic Gain Control for Fast Startup and Low Power
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Solution Overview
Problem
Crystal oscillators consume significant power, particularly in low-power applications, necessitating a reduction in power consumption to extend battery life without compromising startup speed or reliability.
Innovation Solution
A dynamically controlled crystal oscillator with a digital gain control circuit that sets a high gain for fast startup and reduces gain to a lower level during steady-state operation, using a transconductance amplifier and variable capacitors to minimize power consumption while maintaining reliable oscillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high gain is used in crystal oscillator circuits to ensure reliable oscillation startup, then startup reliability is improved, but power consumption increases during steady state operation
Solution Approach 1:
The patent applies dynamic gain control by switching between a first gain value during startup and a second gain value during steady state operation. The gain control circuit dynamically adjusts the loop gain based on the oscillator's operational state, using a higher gain initially to ensure reliable startup and then reducing to a lower gain for power-efficient steady-state operation.
Solution Approach 2:
The patent changes the gain parameter of the negative gain element based on operational conditions. By modifying the loop gain parameter from a first value to a second value, the system optimizes both startup reliability and steady-state power consumption through parameter adaptation.
2Use of energy by moving object
If low gain is used during steady state operation to reduce power consumption, then power efficiency is improved, but startup time increases
Solution Approach 1:
The gain control circuit dynamically adjusts the loop gain based on the oscillator's operational state. During startup, a first gain value is applied to ensure fast and reliable oscillation establishment. Once steady state is achieved, the gain transitions to a second value for power-efficient operation, thus dynamically optimizing both startup time and power consumption.
Solution Approach 2:
The system performs preliminary high-gain operation during startup to quickly establish oscillations, then transitions to low-gain operation for steady state. This preliminary action ensures fast startup while the subsequent low-gain phase maintains power efficiency.
3Use of energy by moving object
If variable loop gain elements and gain control circuits are added to optimize power consumption, then power efficiency is improved, but device complexity increases
Solution Approach 1:
The patent implements a dynamic gain control mechanism that switches between different gain values based on operational state. This dynamic approach optimizes power consumption by using appropriate gain levels for startup and steady-state operations, while the switching mechanism manages the complexity of having multiple gain elements.
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 achieves fast startup and low power consumption during steady-state operation, offering programmable options for trade-offs between power and recovery speed, and is suitable for very low power applications like battery-powered devices.
Implementation Method 1
an oscillator core circuit including a negative gain element having an input and an output
Implementation Method 2
a first variable capacitor having a first terminal connected to the input of the negative gain element, a second terminal, and a control terminal
Implementation Method 3
Crystal oscillators use the resonance characteristics of quartz crystals to provide references for the generation of very accurate clock frequencies
Data Source
AI summary
In one form, an oscillator includes an oscillator core circuit and a dynamic gain control circuit. The oscillator core circuit is for connection to a frequency reference element and provides a first clock signal using a negative gain element having a gain determined by a gain control signal. The dynamic gain control circuit is coupled to the oscillator core circuit for calibrating the gain control signal to a startup value based on oscillations reaching a first threshold during a startup state, and calibrating the gain control signal to a steady-state value based on oscillations falling to a second threshold after an end of the startup state and before entering a steady state. The first threshold is higher than the second threshold. The dynamic gain control circuit operates the oscillator core circuit during the steady state using the steady-state value.