Power Detection via Phase-Shifted Voltage and Current Multiplication
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Solution Overview
Problem
Existing techniques for measuring power delivered to a load, such as an antenna by a power amplifier in RF communications, suffer from inaccuracies due to variations in load impedance, which affect the accuracy of power measurement.
Innovation Solution
A power detection method that involves resonating a circuit element with parasitic inductance or capacitance, detecting load voltage and current, introducing a phase delay between the detected voltage and current, and multiplying these measurements to produce a calibrated power measurement, which is then low-pass filtered to account for variations in temperature, frequency, and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional power measurement techniques are used, then power delivery can be measured, but measurement accuracy deteriorates due to load impedance variations
Solution Approach 1:
The patent replaces conventional voltage and current sensing methods with magnetic field-based sensing. A magnetic sensor detects the magnetic field generated by current flow in the trace, while a capacitor couples to detect voltage, substituting traditional electrical measurement approaches with electromagnetic field measurements that are less sensitive to impedance variations.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary medium for current measurement. Instead of directly measuring current through shunt resistors or series connections that affect circuit impedance, the magnetic sensor detects the magnetic field produced by current flow, using the magnetic field as an intermediary that does not disturb the original circuit operation.
2Reliability
If direct voltage and current sensing is used, then power can be calculated, but measurement reliability worsens due to phase synchronization issues
Solution Approach 1:
The patent applies preliminary action by pre-calibrating the phase delay between voltage and current measurements during manufacturing or initialization. The phase delay value is determined in advance and stored for use during normal operation, eliminating the need for real-time phase synchronization and simplifying the measurement process.
Solution Approach 2:
The patent changes the measurement parameter from direct instantaneous voltage and current products to a phase-adjusted measurement model. By introducing a calibrated phase delay parameter, the system transforms the measurement approach to account for inherent timing differences between voltage and current waveforms, improving reliability.
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 method provides an accurate power measurement that is insensitive to changes in load impedance, ensuring reliable power control in RF communications systems.
Implementation Method 1
resonating a circuit element with a parasitic inductance or parasitic capacitance at a frequency of operation of a load
Implementation Method 2
driving an antenna using a power amplifier
Data Source
Figure 1~2
Figure 3A~3B
Figure 4
AI summary
Some embodiments relate to power detector including a voltage sensor (88) configured to detect a voltage of a load (84) and a current sensor (86) configured to detect a current of the load (84). The power detector also includes circuitry (6) configured to introduce a phase delay between the detected voltage of the load (84) and the detected current of the load (84), thereby producing a voltage measurement and a current measurement. The circuitry (6) is also configured to multiply the voltage measurement and the current measurement.