Crystal Oscillator Wake-Up Timing Using Measured Startup Time
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Solution Overview
Problem
The existing methods for determining the startup time of crystal oscillators in wireless devices are inefficient, leading to higher energy consumption and reduced battery life due to the need for extensive laboratory testing and wide margins to account for crystal and process variations, temperature changes, and other operating conditions.
Innovation Solution
A system comprising a crystal interface, amplifier, level detector, timing circuit, and controller that measures and adjusts the startup time of a crystal oscillator, using optimal settings for efficient startup and switching to robust settings when necessary to ensure oscillation, while dynamically updating the stored startup time based on temperature changes and multiple measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wide margin of startup time is used to account for crystal variations, process variations, and operating condition variations, then reliability of oscillation startup is improved, but energy consumption increases and battery life decreases
Solution Approach 1:
The patent dynamically adjusts the startup time margin parameter based on measured actual startup times and operating conditions (temperature, crystal variations). Instead of using a fixed wide margin, the system adapts the margin parameter to match actual performance, reducing unnecessary energy consumption while maintaining reliable oscillation startup across varying conditions
Solution Approach 2:
The system performs self-characterization by measuring its own actual startup time and using this information to optimize future startup timing. The device learns from its own performance data and automatically adjusts its operation to minimize energy consumption while ensuring reliable oscillation establishment
2Stability of the object's composition
If a wide margin of startup time is used to account for temperature changes and operating condition variations, then stability of oscillation is improved, but startup time increases
Solution Approach 1:
The patent transitions from a static, conservative startup time margin to a dynamic approach where the startup time is continuously measured and adjusted based on actual performance and environmental conditions. The system adapts its startup timing in real-time, reducing unnecessary wait time while maintaining stable oscillation across temperature and operating condition variations
Solution Approach 2:
The system implements feedback by measuring the actual startup time and using this information to adjust future startup timing. The measured startup time feeds back into the control logic, allowing the system to optimize the balance between startup time and oscillation stability based on actual performance data
3Manufacturing precision
If extensive laboratory testing is performed to identify worst case startup time, then manufacturing precision is improved, but device complexity and testing time increase
Solution Approach 1:
The patent eliminates the need for extensive external laboratory testing by enabling each device to perform self-characterization. The device automatically measures its own startup time and stores this information for use in normal operation, replacing complex manufacturing testing processes with simple on-device measurement
Solution Approach 2:
The system creates a simplified model of the startup characteristics by measuring actual startup time once and storing it as a reference value. This copied information is then used to optimize future operations without requiring repeated complex testing, replacing elaborate manufacturing characterization with a single simple measurement
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 minimizes startup time, reduces energy consumption, and optimizes battery life by using measured startup times to determine wake-up times, ensuring stable oscillation just-in-time for scheduled operations while conserving power.
Implementation Method 1
A crystal oscillator uses the mechanical resonance of a crystal to create an oscillation signal having a precise frequency
Implementation Method 2
The crystal oscillator also includes a crystal amplifier that provides a 'negative' resistance to cancel the losses of the crystal to establish and maintain oscillation
Implementation Method 3
The level detector provides an oscillation indication when a target amplitude is detected
Implementation Method 4
The controller activates the crystal amplifier and uses the timing circuit and the level detector to measure a startup time of oscillation
Data Source
AI summary
An oscillation circuit including a crystal interface, a crystal amplifier, a level detector, a timing circuit, and a controller. When activated, the crystal amplifier drives a crystal coupled to the crystal interface to establish oscillation, and the level detector indicates when a target amplitude is detected. The controller activates the crystal amplifier and uses the timing circuit and the level detector to measure a startup time of oscillation. The measured startup time is used in calculating a wake up time from a sleep mode in time to perform an operation at a scheduled time. The startup time may be adjusted or averaged and may be remeasured with temperature change. A method of minimizing startup time of a crystal oscillator includes measuring startup time for determining a delay value for programming a wakeup circuit. Robust startup settings may be used in the event of startup failure due to a sleepy crystal.