Oscillator Drive Trim Circuit for Gyroscope Phase Calibration
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Solution Overview
Problem
The existing methods for phase calibration of oscillator drive circuits in vibratory gyroscopes are time-consuming, costly, and prone to errors due to the need for iterative testing and external calibration equipment.
Innovation Solution
A trim circuit is integrated into the oscillator drive circuit within an integrated circuit of the vibratory gyroscope, allowing for phase calibration to be performed internally. This circuit includes comparators and a processing element that determine the phase lag between signals and produce a trim code to adjust the phase shift component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external tester and test busses are used to measure phase lag, then phase calibration can be performed, but test time increases and test costs increase
Solution Approach 1:
The phase calibration functionality is extracted from the external tester and integrated directly into the oscillator drive circuit through the trim circuit. The processing element within the integrated circuit performs phase lag measurement and trim code generation internally, eliminating the need for external measurement equipment and iterative testing procedures.
Solution Approach 2:
The oscillator drive circuit performs its own phase calibration using the integrated trim circuit. The processing element measures the phase lag between signals and automatically generates trim codes to adjust the phase shift circuit, enabling the system to self-calibrate without external intervention or iterative external testing.
2Measurement precision
If analog signals are routed through test busses to external tester, then phase lag measurement is possible, but measurement precision deteriorates due to noisy environment
Solution Approach 1:
The phase measurement functionality is extracted from the noisy external test environment and integrated into the protected internal environment of the oscillator drive circuit. All signal processing and measurement occur within the integrated circuit, isolating the measurement process from external electromagnetic interference and noise.
Solution Approach 2:
The trim circuit acts as an intermediary between the phase shift circuit and the processing element, providing a controlled internal pathway for signal measurement. This intermediary structure eliminates the need for external test busses that expose signals to noisy environments, maintaining signal integrity throughout the measurement process.
3Measurement precision
If iterative test procedures are used for phase calibration, then calibration accuracy can be achieved, but productivity decreases
Solution Approach 1:
The processing element is pre-configured within the integrated circuit to perform phase lag measurement and trim code generation in a single operational sequence. The trim circuit is designed with predetermined functionality to achieve calibration in one pass, eliminating the need for repeated iterative testing while maintaining calibration accuracy.
Solution Approach 2:
The oscillator drive circuit performs self-calibration through the integrated trim circuit, automatically measuring phase lag and generating appropriate trim codes without requiring external iterative adjustment. This self-service capability achieves calibration accuracy while significantly improving test throughput by eliminating repetitive external testing cycles.
4Measurement precision
If phase calibration is performed externally, then calibration can be completed, but device complexity increases due to additional external equipment
Solution Approach 1:
The trim circuit is merged with the oscillator drive circuit within the same integrated circuit. The processing element, comparators, and phase shift circuit are combined into a unified internal structure, eliminating the need for separate external calibration equipment and reducing overall system complexity while maintaining calibration functionality.
Solution Approach 2:
The processing element within the integrated circuit serves multiple functions: it controls the oscillator drive circuit, measures phase lag between signals, generates trim codes, and adjusts the phase shift circuit. This multi-functional integration replaces multiple external specialized equipment, reducing device complexity while preserving phase calibration capability.
Data Source
AI summary
An oscillator drive circuit and a trim circuit are implemented inside an integrated circuit of a sensor. The drive circuit provides an oscillating drive signal at a resonant frequency to drive a movable mass of the sensor. The drive circuit includes a phase shift circuit having an input for receiving a first signal indicative of an oscillation of the movable mass and having an output. The phase shift circuit adds a phase shift component to the first signal and produces a second signal shifted in phase by the phase shift component. The trim circuit includes a first comparator for receiving the first signal, a second comparator for receiving the second signal, and a processing element. The processing element determines a phase lag between the first and second signals and produces trim code for use by the phase shift circuit, the trim code being configured to adjust the phase shift component.