Filter Oscillator Calibration for Accurate On-Chip Tuning
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Solution Overview
Problem
Existing filter calibration methods in communication devices are either complex and costly or lead to inaccurate component value approximations due to variability in on-chip components, especially when relying on secondary methods that assume consistent test circuit component measurements across the chip.
Innovation Solution
Reconfiguring the filter as an oscillator during calibration mode, using switches to convert the negative feedback loop to a positive feedback loop, and measuring oscillation parameters to adjust filter components to achieve desired characteristics without external elements or complex signal generation mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct methods are used to measure performance characteristics of actual filter components, then filter calibration accuracy is improved, but device complexity and cost increase due to complex signal generation and analysis mechanisms
Solution Approach 1:
The filter uses its own internal noise as the test signal, eliminating the need for external signal generation mechanisms. The filter's inherent thermal noise is sufficient for calibration purposes, allowing the system to calibrate itself without additional complex equipment.
Solution Approach 2:
The patent extracts and utilizes the filter's own internal noise characteristics for calibration, removing the dependency on external signal sources. By measuring the filter's intrinsic noise performance, the system achieves accurate calibration without adding complex external test equipment.
2Device complexity
If secondary calibration methods are used with test circuitry on a separate on-chip test circuit, then device complexity is reduced, but measurement precision deteriorates due to component variability across different chip areas
Solution Approach 1:
The filter calibrates itself using its own internal noise characteristics rather than relying on separate test circuitry. This self-service approach ensures that the calibration reference is located exactly where needed, eliminating errors from spatial variability in component characteristics across the chip.
Solution Approach 2:
The calibration is performed locally within the filter structure itself, using the filter's own components and inherent noise. This local approach ensures that the calibration reference matches the actual operating conditions and component characteristics of the filter, avoiding discrepancies from using distant test circuitry.
3Measurement precision
If traditional calibration methods with external elements are used, then measurement precision may be maintained, but device complexity and cost increase
Solution Approach 1:
The filter generates and measures its own noise for calibration purposes, requiring no external test equipment or additional calibration components. This self-sufficient approach reduces manufacturing complexity and cost while maintaining calibration accuracy through direct measurement of the filter's actual performance.
Solution Approach 2:
The filter's inherent noise, which is normally considered an unwanted byproduct, is repurposed as a useful calibration signal. This multi-functional use of the filter's own characteristics eliminates the need for separate calibration mechanisms, reducing overall system complexity and manufacturing cost.
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
Enables accurate and cost-effective filter calibration by directly measuring and adjusting filter components in situ, reducing the need for external calibration tools and improving calibration speed, with oscillations induced within fractions of a microsecond.
Implementation Method 1
reconfiguring the filter as an oscillator during calibration mode. Switches and/or other implementations of reconfiguring a filter are used to reconfigure the negative feedback loop of the filter to a positive feedback loop
Data Source
AI summary
Calibrating a filter is disclosed. The filter is reconfigured as an oscillator during calibration. Switches and/or other implementations of reconfiguring a filter are used to reconfigure the negative feedback loop of the filter to a positive feedback loop. The oscillation parameters are then measured to adjust the components of the filter to achieve an oscillation that corresponds to a desired filter characteristic.