Position-Sensing Circuit Using Current Mirror Load Isolation
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Solution Overview
Problem
Existing grating positioning sensors face challenges in achieving differential current sensing due to common polarity structures and impedance properties, which affect signal injection efficiency and operation bandwidth in high-frequency circuits.
Innovation Solution
A processing device comprising light sensors, a signal processing unit, a current mirror unit, and a transforming unit, where the signal processing unit provides load isolation and the current mirror unit mirrors current signals to form differential current signals, which are then transformed into voltage signals, effectively isolating impedance effects and improving signal injection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light sensors with common polarity structure are used, then manufacturing is simplified, but differential current sensing cannot be achieved
Solution Approach 1:
The patent introduces a current mirror circuit as an intermediary component between the light sensors and the transforming unit. This current mirror receives current signals from light sensors with common polarity structure and generates differential current signals, thereby enabling differential current sensing capability without requiring complex light sensor structures.
2Device complexity
If direct coupling high frequency circuit is used, then circuit complexity is reduced, but impedance load effect influences signal injection efficiency and operation bandwidth
Solution Approach 1:
The patent segments the circuit into distinct functional modules: signal processing unit, current mirror unit, and transforming unit. The signal processing unit provides load isolation that separates the impedance characteristics of light sensors from the transforming unit, thereby improving signal injection efficiency and operation bandwidth while maintaining manageable circuit complexity through modular design.
3Productivity
If load isolation is provided, then signal injection efficiency is improved, but device complexity increases
Solution Approach 1:
The current mirror unit serves multiple functions simultaneously: it converts current signals to differential current signals, provides load isolation to improve signal injection efficiency, and maintains compatibility with common polarity light sensor structures. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device 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 solution enables the achievement of differential current sensing and reduces the influence of impedance and output load on light sensors, enhancing signal injection efficiency and operation bandwidth.
Implementation Method 1
the light sensors sense a light field to generate a plurality of position sensing current signals
Data Source
AI summary
A processing device for position sensing includes a plurality of light sensors, a signal processing unit, a current mirror unit and a transforming unit. The light sensors are spaced apart from each other and sense a light field to generate a plurality of position sensing current signals. The signal processing unit receives the position sensing current signals and provides a load isolation, so as to generate a first current signal and a second current signal. The second current signal is transmitted to a node. The first and second current signals respectively correspond to a first group and a second group of light sensors. The current mirror unit mirrors the first current signal to a third current signal. The third current is transmitted to the node. The transforming unit transforms a differential current signal formed by the second and third current signals on the node to a voltage signal.