RF IC Calibration Architecture Using Internal Switchable Paths
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Solution Overview
Problem
Accurate calibration of radio frequency integrated circuits (RF ICs) used in transceiver RF systems is challenging due to the need for elaborate testing equipment and environmental factors that affect signal quality, especially when measuring phase and signal amplitude alignment in multi-antenna/multi-transceiver systems.
Innovation Solution
The implementation of on-chip switchable internal calibration paths allows for direct coupling of RF IC components to a test system, isolating other circuitry and enabling calibration at lower frequencies, thereby mitigating environmental influences and allowing for periodic self-calibration within the final system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If over-the-air calibration is performed at high frequencies (30 GHz or more), then calibration can be done in the final system environment, but measurement accuracy deteriorates due to environmental factors that alter, shield, attenuate, or distort signals
Solution Approach 1:
The patent extracts the calibration function from the complex over-the-air environment and implements it within the RF IC itself through internal calibration paths. This allows calibration measurements to be performed internally without external environmental interference, while still enabling periodic self-calibration in the final system through test signal injection ports.
Solution Approach 2:
The patent introduces test signal injection ports as intermediary interfaces that allow controlled test signals to enter the RF IC for calibration purposes. These ports serve as mediators between the external test environment and the internal calibration circuitry, enabling accurate measurements without direct over-the-air exposure.
2Reliability
If elaborate testing equipment is used for over-the-air calibration, then calibration can be performed in the final system, but device complexity and testing cost increase
Solution Approach 1:
The patent extracts the calibration functionality from complex external testing equipment and integrates it directly into the RF IC through internal calibration paths and test signal injection ports. This eliminates the need for elaborate external testing equipment while maintaining calibration capability in the final system.
Solution Approach 2:
The patent implements self-calibration capability within the RF IC, allowing the device to calibrate itself periodically without requiring complex external testing equipment. The internal calibration paths enable the RF IC to perform self-diagnosis and adjustment, reducing dependency on elaborate external test systems.
3Measurement precision
If direct connection calibration is implemented, then environmental factors are eliminated and calibration accuracy improves, but additional on-chip circuitry is required
Solution Approach 1:
The patent segments the RF IC into functional sections with dedicated calibration paths. Internal calibration paths are created as separate routed connections that can be selectively activated, allowing calibration measurements to be performed on specific circuit blocks without affecting other portions of the device.
Solution Approach 2:
The patent implements dynamic switching capability through on-chip switches that can selectively connect or disconnect calibration paths. This allows the calibration circuitry to be activated only when needed, and the same physical infrastructure to serve both calibration and operational functions at different times.
Data Source
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AI summary
A calibration architecture that enables accurate calibration of radio frequency (RF) integrated circuits (ICs) chips used in transceiver RF systems in a relatively simple testing environment. Embodiments of the invention include one or more on-chip switchable internal calibration paths that enable direct coupling of a portion of the on-chip circuit to an RF test system while isolating other circuitry on the chip. Periodic self-calibration of an RF IC can be performed after initial factory calibration, so that adjustments in desired performance parameters can be made while such an IC is embedded within a final system, and/or to take into account component degradation due to age or other factors.