Amplifier Power Measurement via Supply-Terminal Detection
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Solution Overview
Problem
Designing a satisfactory power detector for wireless communications circuitry in electronic devices is challenging due to signal loss and degradation of noise figure when a power detector is conventionally coupled at the input of low noise amplifiers.
Innovation Solution
Implementing a power detector coupled to the power supply terminal of amplifiers, with control circuitry adjusting input and output matching circuits and bias voltages based on measured values, and controlling switches to optimize amplifier performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a power detector is conventionally coupled at the input of low noise amplifiers, then power measurement is achieved, but signal loss and degradation of noise figure occur
Solution Approach 1:
The patent introduces an intermediary approach by coupling the power detector to the power supply terminal rather than directly at the signal input. This allows power measurement to be obtained through monitoring the power supply current, which correlates with the amplifier's output power, without inserting the detector into the signal path. This intermediary measurement method avoids signal loss while maintaining measurement capability.
Solution Approach 2:
The power supply terminal serves multiple functions: it provides power to the amplifier and simultaneously serves as a measurement point for power detection. By utilizing the existing power supply infrastructure for dual purposes (power delivery and power measurement), the patent eliminates the need for a separate signal path detector, thereby avoiding signal loss and noise figure degradation.
2Measurement precision
If a power detector is conventionally coupled at the input of low noise amplifiers, then power measurement is achieved, but noise figure degradation occurs
Solution Approach 1:
The patent uses the power supply terminal as an intermediary measurement point that does not interfere with the signal path. By measuring power through the power supply current rather than inserting a detector in the signal path, the intrinsic noise characteristics of the low noise amplifier remain unaffected, preserving the noise figure.
Solution Approach 2:
The patent extracts the power measurement function from the signal path and relocates it to the power supply domain. This separation ensures that the power detection operation does not introduce additional noise or degrade the noise figure of the low noise amplifier, as the measurement is performed on a different electrical domain (power supply current rather than signal current).
Data Source
AI summary
Wireless circuitry is provided that includes an amplifier configured to receive a radio-frequency signal, a measurement circuit coupled to a power supply terminal of the amplifier and configured to output a measured value, and control circuitry configured to adjust one or more components associated with the amplifier based on the measured value output from the measurement circuit. The measurement circuit can include a transformer or a current mirror circuit. The control circuitry can selectively adjust an input matching circuit, an output matching circuit, and/or one or more bias voltages for the amplifier based on the measured value. The control circuitry can switch one or more amplifiers in and out of use depending on the measured value.