Crystal Oscillator Signal Conditioner for Compliant Clock Startup
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Solution Overview
Problem
Crystal oscillators are slow starters due to high Q values, making it difficult to predict and minimize startup time, leading to noncompliant clock signals that can invalidate system integrity until a predetermined delay period has elapsed, which is often longer than necessary.
Innovation Solution
A self-enabling signal conditioner with first and second signal paths and a coincident gate that toggles the clock signal only when both paths reach specific amplitude levels, ensuring compliance in timing and amplitude without the need for extended reset delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predetermined delay period is used to ensure compliant clock signal, then system reliability is improved, but startup time is increased
Solution Approach 1:
The signal conditioner performs preliminary actions by continuously monitoring the oscillation signal amplitude and preparing the clock signal in advance. The circuit is designed to detect when the oscillation reaches sufficient amplitude and automatically transitions to producing a compliant clock signal, eliminating the need for a conservative predetermined delay period while ensuring system reliability.
2Reliability
If a long predetermined delay period is used to cover all crystal oscillator variations, then clock signal compliance is guaranteed, but productivity is reduced
Solution Approach 1:
The signal conditioner dynamically adjusts its operation based on the real-time amplitude of the oscillation signal. Rather than using a fixed delay period, the circuit continuously monitors the oscillation strength and transitions to compliant clock signal generation as soon as the oscillation reaches the required amplitude threshold, adapting to each specific crystal oscillator's startup characteristics.
Solution Approach 2:
The circuit employs feedback mechanisms where the oscillation signal is continuously monitored and fed back to the signal conditioner. This feedback loop allows the system to detect when the oscillation has reached sufficient amplitude and automatically enable compliant clock signal generation, ensuring clock signal compliance while minimizing startup time for each specific oscillator instance.
3Reliability
If complex reset and synchronization circuitry is used to handle noncompliant signals, then system reliability is improved, but device complexity is increased
Solution Approach 1:
The patent extracts the compliance assurance function from complex reset and synchronization circuitry and integrates it directly into the signal conditioner. By embedding amplitude monitoring and conditional clock signal generation within the signal conditioner itself, the design eliminates the need for separate complex reset controllers and synchronization circuits, reducing overall device complexity while maintaining system reliability.
Solution Approach 2:
The signal conditioner merges multiple functions into a single integrated circuit: oscillation amplitude monitoring, clock signal generation, and compliance assurance. This consolidation combines what would traditionally require separate reset circuitry, synchronization logic, and signal conditioning stages into one unified block, simplifying the overall system architecture while ensuring reliable operation.
Data Source
AI summary
A signal conditioner for conditioning a differential oscillation signal into a compliant clock signal including first and second signal paths and a coincident gate. The first signal path toggles a first binary signal in response to the differential oscillation signal when the differential oscillation signal reaches a small amplitude level. The second signal path toggles a second binary signal in response to the differential oscillation signal only when the differential oscillation signal reaches a large amplitude level that is greater than the small amplitude level. The coincident gate toggles the clock signal high only when the first and second binary signals are both high, and toggles the clock signal low only when the first and second binary signals are both low. When the clock signal begins toggling, it may skip one or more cycles but is nonetheless compliant in terms of timing and amplitude.