Feedback Voltage Detector Circuit for Low-Input Sensing
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Solution Overview
Problem
Existing voltage detectors in wireless communication circuits are unable to effectively detect low input voltages, leading to potential damage to back-end circuits due to excessive input voltages.
Innovation Solution
A voltage detector and communication circuit design incorporating an AC coupling circuit, feedback amplifier, and auxiliary circuit that generate differential input voltages and output currents, allowing for increased sensitivity in voltage detection by amplifying the output voltage in response to both input voltage and sink current variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the voltage detector uses conventional detection circuitry, then it can detect high input voltages, but it cannot detect low input voltages with sufficient sensitivity
Solution Approach 1:
The patent implements a feedback mechanism where the output voltage of the detector is fed back to the negative terminal of the operational amplifier. This feedback loop allows the circuit to continuously adjust and amplify the differential voltage signal, enabling sensitive detection of low input voltages while maintaining stable operation. The feedback ensures that even small voltage differences are amplified sufficiently to trigger accurate detection.
Solution Approach 2:
The patent introduces an operational amplifier as an intermediary element that mediates between the differential input voltages and the detection threshold. The op-amp amplifies the small voltage difference between its positive and negative terminals, converting微弱 voltage signals into significant output voltage changes that can reliably trigger the detection circuit. This intermediary amplification stage is crucial for detecting low input voltages with high sensitivity.
2Measurement precision
If the voltage detector amplifies the output voltage in response to both input voltage and sink current variations, then detection sensitivity increases, but circuit complexity increases
Solution Approach 1:
The operational amplifier in the patent serves multiple functions simultaneously: it amplifies the differential input voltage, provides feedback for stability, and works in conjunction with the sink current to enhance detection sensitivity. By making the op-amp multi-functional, the circuit achieves high detection sensitivity without adding numerous separate components, thus managing complexity while improving performance.
Solution Approach 2:
The patent utilizes parameter changes in the sink current to modulate the detection sensitivity. By varying the sink current parameter, the circuit can adjust its response to different input voltage levels without requiring structural modifications. This parameter-based control allows the same circuit structure to adapt to different detection requirements, reducing overall system complexity.
Data Source
AI summary
Disclosed is a voltage detector and a communication circuit capable of detecting a low input voltage. The voltage detector includes: an alternating-current coupling circuit generating a first and a second input voltages according to a source input voltage; a feedback amplifier outputting a branch current according to a sink current including the branch current, and determining an output voltage according to the first input voltage and the amount of the branch current; and an auxiliary circuit outputting the amount of the sink current according to the second input voltage. When the sink current increases as the second input voltage rises, the branch current also increases, so that the output voltage not only rises as the first input voltage rises but also rises as the branch current increases. This feature allows a lower input voltage to be detectable by the detection of the risen output voltage.