MOS Envelope Detection Circuit With Adaptive Bias for Wide Dynamic Range
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Solution Overview
Problem
Conventional electronic envelope detection circuits face challenges in dynamically adapting the biasing point and conversion gain to variations in the average power of radiofrequency input signals, leading to limited dynamic range and signal distortion.
Innovation Solution
An electronic envelope detection circuit with a MOS transistor-based input signal detecting circuit and a processing circuit that dynamically regulates the biasing point through a control signal, using a transformer configuration to multiply the input signal and control signal, allowing for dynamic adaptation of the conversion gain and extended dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional envelope detector with a fixed biasing point amplifier is used, then the circuit complexity is low, but the dynamic range is limited and the conversion gain cannot be maximized when the average power of the input signal varies
Solution Approach 1:
The patent applies dynamics by making the biasing point of the amplifier variable through a control signal that dynamically adjusts the operating point. The amplifier transitions from a fixed biasing configuration to one where the biasing voltage can be modulated in response to input signal power variations, thereby extending the dynamic range while maintaining adaptability to different signal conditions
Solution Approach 2:
The patent implements feedback by using a portion of the output signal or a derived control signal to adjust the biasing point of the amplifier. This feedback mechanism allows the circuit to automatically adapt to variations in input signal average power, maximizing conversion gain across different operating conditions without requiring complex external control circuits
2Adaptability or versatility
If the biasing point is fixed to maximize conversion gain, then the sensitivity is maximized, but the dynamic range is limited and distortion occurs when input signal power varies
Solution Approach 1:
The patent makes the biasing point dynamic by introducing a control signal that adjusts the amplifier's operating point in real-time. This dynamic adjustment allows the circuit to maintain optimal conversion gain across varying input signal power levels while preventing the clipping and distortion that occur with fixed biasing configurations
Solution Approach 2:
The patent changes the biasing voltage parameter of the amplifier based on the average power of the input signal. By modulating this key parameter, the circuit adapts its conversion gain to match the input signal conditions, thereby maintaining high sensitivity across a wide dynamic range while avoiding signal distortion
3Adaptability or versatility
If a feedback circuit is added to adapt the biasing point dynamically, then the dynamic range is extended, but the circuit complexity increases
Solution Approach 1:
The patent achieves multi-functionality by designing the amplifier to simultaneously perform signal amplification and envelope detection while its biasing point is dynamically controlled. This integrated approach allows the same circuit element to adapt to different signal conditions without requiring separate complex feedback control circuits, thereby extending dynamic range with minimal additional complexity
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
The circuit effectively adapts to variations in input signal power, enhancing conversion efficiency and extending the dynamic range while reducing distortion, thereby improving the sensitivity and demodulation quality of the envelope detection process.
Implementation Method 1
using a transformer configuration to multiply the input signal and control signal
Data Source
AI summary
An electronic envelope detection circuit includes an input signal detecting circuit having at least one MOS transistor configured to receive a radiofrequency input signal and to deliver an internal signal on the basis of the input signal. The biasing point of the at least one transistor is controlled by the input signal and a control signal. A processing circuit that is coupled to the input signal detecting circuit is configured to deliver a low-frequency output signal on the basis of the internal signal and further deliver the control signal on the basis of the output signal. In operation, the value of the control signal decreases when the average power of the input signal increases, and vice versa.