Configurable Rectifier for Low-Level Signal Detection
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Solution Overview
Problem
Existing signal level detection systems using diode circuits struggle to detect small AC signals due to their inherent non-zero threshold voltage, which prevents the rectification of signals below this voltage.
Innovation Solution
A configurable rectifier circuit comprising an inverting and non-inverting rectifier with the same circuit topology but different connectivity, allowing configuration as either an inverting or non-inverting rectifier, and a shared biasing current, effectively converting differential input signals into differential output signals regardless of signal sign.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diode circuit is used for rectification, then the circuit structure is simple, but it cannot rectify small AC signals whose amplitude is below the threshold voltage
Solution Approach 1:
The rectifier is divided into multiple parallel branches, each containing gain devices and degeneration devices. This segmentation allows each branch to contribute to the overall rectification function while providing signal amplification, enabling the circuit to handle small input signals that would be below the threshold of a single diode.
Solution Approach 2:
Multiple rectifier branches are combined in parallel configuration, merging their individual rectification capabilities. The combined effect provides both the rectification function and sufficient gain to detect small signals, resolving the contradiction between simple structure and reliable rectification of small AC signals.
2Measurement precision
If the threshold voltage of the diode is reduced, then small AC signals can be rectified, but the rectification efficiency and output signal level decrease
Solution Approach 1:
The circuit uses controllable gain devices whose parameters can be adjusted to optimize performance. By changing the gain parameter of the amplification devices, the circuit can maintain high detection sensitivity for small signals while preserving adequate rectification efficiency through proper parameter selection and biasing.
Solution Approach 2:
The rectifier employs a composite structure combining different types of active devices (gain devices and degeneration devices) with complementary characteristics. This composite configuration allows the circuit to achieve both high sensitivity for small signal detection and maintained rectification efficiency through the synergistic interaction of the different device components.
3Measurement precision
If a complementary rectifier configuration is used to increase gain, then small signals can be detected, but the circuit complexity increases
Solution Approach 1:
The complementary rectifier configuration serves multiple functions simultaneously: it provides signal amplification for small signal detection, performs rectification of the AC signal, and generates the differential output signal. This multi-functionality reduces the need for separate stages, thereby limiting the increase in overall circuit complexity despite the enhanced detection capability.
Solution Approach 2:
The inverting and non-inverting rectifier branches are configured with asymmetric connectivity to the differential input signal, yet maintain the same circuit topology. This asymmetric configuration enables differential output generation while reusing the same topological structure, thereby increasing detection capability without proportionally increasing circuit 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
Enables the detection of low-level signals by providing a higher gain and effectively rectifying small AC signals, overcoming the limitations of traditional diode-based systems.
Implementation Method 1
a rectification circuit is needed. By rectification, an AC signal is converted into a DC signal
Implementation Method 2
a current source for establishing a biasing current for the complementary rectifier
Data Source
AI summary
A signal level detector and detecting method are provided. In one implementation a method includes receiving a differential input signal; incorporating two configurable rectifiers of the same circuit topology; configuring a first one of the two configurable rectifiers as a inverting rectifier to generate an inverting end of an output signal in response to an absolute value of the differential input signal; and configuring a second one of the two configurable rectifiers as a non-inverting rectifier to generate a non-inverting end of the output signal.