Resonant Oscillator Startup Using Tuned AC-Coupled Impetus
Solution Overview
Problem
Existing oscillator circuits face challenges in achieving fast and reliable startup times due to issues like resonator overdrive, self-cancellation, and high power consumption, particularly because they often rely on complex control circuitry and impetus signals that are not specifically targeted at the resonant frequency, leading to inefficient energy delivery and prolonged startup times.
Innovation Solution
The implementation of an AC-coupled tunable oscillator that delivers an impetus signal targeted at the resonant frequency of the resonator, using a capacitor to minimize interference with the main oscillator and employing compare and control circuitry to calibrate and disable the signal accurately, thereby reducing startup time and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If an impetus signal is applied to start the oscillator, then startup time is reduced, but the resonator may become overdriven or self-cancelled leading to unreliable operation
Solution Approach 1:
The patent applies periodic impetus signals at the resonant frequency to initiate and sustain oscillator operation. The signal is applied periodically during startup and can be adjusted or discontinued once oscillation is established, enabling fast startup while preventing overdrive conditions that would compromise reliability.
2Device complexity
If white noise is used to initiate oscillation, then the circuit is simple to implement, but energy is wasted at spurious frequencies and startup time increases
Solution Approach 1:
The patent changes the frequency parameter of the impetus signal from broad-spectrum white noise to a specific frequency matching the resonant frequency of the resonator. This targeted frequency approach significantly reduces startup time by concentrating energy where it is needed, while the circuit remains relatively simple to implement.
3Reliability
If the impetus signal is continuously applied to ensure reliable startup, then startup reliability is improved, but power consumption increases
Solution Approach 1:
The impetus signal is applied periodically rather than continuously. The signal is activated during the startup phase to ensure reliable oscillation initiation, then discontinued or reduced once the oscillator is running, thereby maintaining startup reliability while minimizing unnecessary power consumption during normal operation.
4Reliability
If complex control circuitry is used to manage the impetus signal, then startup reliability is improved, but device complexity increases
Solution Approach 1:
The oscillator circuit utilizes its own resonant characteristics to control the impetus signal application. The resonator's natural resonance provides feedback that indicates when oscillation has started, allowing the control circuit to automatically discontinuate the impetus signal without requiring complex external monitoring and control circuitry.
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 enables rapid and reliable startup of oscillators by accurately targeting the resonant frequency, reducing sensitivity to overdrive and self-cancellation, and minimizing power consumption, eliminating the need for complex counter and detection circuitry.
Implementation Method 1
A resonant element, such as a piezoelectric resonator or resonant micro-electromechanical system (MEMS) element, to set the frequency of the clock
Implementation Method 2
A common form of clocking circuit utilizes a resonant element, such as a piezoelectric resonator
Implementation Method 3
Circuits that applied this method involved placing the circuit into two different states. During startup the circuit would be placed in a first state that would allow a large amount of noise in the circuit. Thermal noise is low energy white noise and is always present in circuits.
Data Source
AI summary
A startup circuit 200 and method 700 is provided for quickly starting up a resonator based oscillator. Tunable oscillator 201 provides an impetus signal to oscillator 205 through capacitor 202. The impetus signal has a frequency that is an estimate of the resonant frequency of resonator 205. The circuit measures the frequency of oscillator 204 and the frequency of tunable oscillator 201. The circuit then adjusts the frequency of tunable oscillator 201 such that the frequency of the tunable oscillator is substantially equal to the resonant frequency of the resonator 205 and stores a data state necessary for the tunable oscillator 201 to generate a signal with this target frequency in the future. During an ensuing startup cycle the stored data state causes the impetus signal delivered by tunable oscillator 202 to be substantially equal to the target frequency of oscillator 204 which improves startup performance.