RFID Oscillator Calibration via Non-Volatile Memory
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing RFID tag oscillators require bulky and high-power consumption mechanisms, long start-up times, extra power for phase-locked loops, and permanent trimming arrangements that are expensive and non-dynamically calibratable, impacting performance and efficiency.
Innovation Solution
A method for calibrating an RFID tag oscillator by storing a calibration value in non-volatile memory, which is calculated from a test signal to correct the oscillator frequency, allowing for pre-calibration before power-up and dynamic adjustment of clock signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a crystal or L-C tank reference is used to provide a precise local reference frequency, then frequency precision is improved, but device size and power consumption increase
Solution Approach 1:
The patent applies preliminary action by pre-calibrating the oscillator frequency during manufacturing and storing the calibration values in non-volatile memory. This allows the oscillator to be pre-adjusted to the correct frequency without requiring continuous calibration during operation, thereby reducing power consumption while maintaining frequency precision.
Solution Approach 2:
The patent uses copying by storing digital calibration values in non-volatile memory that represent the oscillator's frequency characteristics. These stored values are copies of the ideal frequency parameters that can be retrieved and applied without requiring the physical presence of high-precision reference components like crystals during operation.
2Stability of the object's composition
If a phase-locked loop arrangement is used to provide a reference frequency, then frequency stability is improved, but start-up time and device complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-calibrating the oscillator during manufacturing and storing calibration values in non-volatile memory. This eliminates the need for time-consuming phase-locked loop convergence during start-up, as the oscillator is already configured to the correct frequency before deployment.
Solution Approach 2:
The patent extracts the calibration function from the operational phase and moves it to the manufacturing phase. By taking out the frequency calibration process and performing it beforehand, the system avoids the complexity and start-up time penalties of continuous phase-locked loop operation.
3Manufacturing precision
If a trimming arrangement is used to calibrate the oscillator, then manufacturing precision is improved, but device cost and adaptability decrease
Solution Approach 1:
The patent applies dynamics by enabling the oscillator calibration to be dynamically adjusted through software-based frequency synthesis. Instead of fixed hardware trimming, the system can adaptively select from multiple calibration values stored in non-volatile memory, allowing dynamic calibration for different operating conditions and frequencies.
Solution Approach 2:
The patent uses parameter changes by storing multiple calibration values corresponding to different frequency parameters in non-volatile memory. This allows the oscillator to be reconfigured for different operating frequencies and conditions by simply changing the selected calibration value, providing both precision and adaptability.
Data Source
AI summary
In accordance with one aspect of the present invention, there is provided a method of calibrating an oscillator within a radio-frequency identification (RFID) circuit for use in an RFID tag. The oscillator has an oscillation frequency. A calibration value is stored within a non-volatile memory associated with the RFID circuit. The oscillator is calibrated in accordance with the calibration value. The storing of the calibration value includes recovering a reference frequency from a test signal supplied to the RFID circuit, calculating the calibration value to correspond to a difference between the recovered reference frequency and the oscillator frequency, and writing the calibration value to the non-volatile memory.