Detection Device Ground-Domain Segmentation to Limit Isolator Delay
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Solution Overview
Problem
Existing detection devices face limitations due to propagation delay in isolators, which affect communication speed and hinder accurate hover detection performance.
Innovation Solution
The detection device employs a configuration with a sensor circuit, AFE circuit, control circuit, and reference potential generation circuit, utilizing first and second isolators to maintain separate reference potentials for different circuit blocks, reducing propagation delay and enhancing signal transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If isolators are provided on power supply path and signal transmission path to electrically isolate circuits, then electromagnetic interference is reduced and detection accuracy is improved, but propagation delay of the isolator limits communication speed
Solution Approach 1:
The system is divided into two separate ground potential domains: a first reference potential (fixed) for peripheral circuits and processing devices, and a second reference potential (synchronized square wave) for the detection block containing the AFE circuit and control circuit. This segmentation allows each domain to operate independently with its own reference potential, eliminating the need for isolators on internal signal paths while maintaining electromagnetic isolation between domains through the ground potential difference.
Solution Approach 2:
The patent introduces a reference potential generation circuit as an intermediary component that converts the first reference potential into a second reference potential synchronized with the detection signal. This intermediary enables galvanic isolation between the peripheral circuits operating at fixed potential and the detection circuits operating at varying potential, eliminating propagation delay issues while maintaining electrical isolation.
2Measurement precision
If the ground potential of the detection block is set to a periodically varying potential synchronized with detection signals, then hover detection accuracy is improved, but isolators are required on signal transmission paths which increases device complexity
Solution Approach 1:
The AFE circuit and control circuit are merged into a single detection block that operates with a common second reference potential. This merging eliminates the need for isolators between these two circuits, as they now share the same ground potential domain. The detection block is electrically isolated from peripheral circuits through the reference potential generation circuit, reducing overall device complexity while maintaining detection accuracy.
3Reliability
If isolators are provided on transmission paths, then electrical isolation between circuits is achieved, but signal transmission speed is reduced due to propagation delay
Solution Approach 1:
The reference potential generation circuit performs preliminary action by pre-converting the first reference potential into a second reference potential that is synchronized with the detection signal waveform. This preliminary conversion establishes the proper ground potential domain before signals are transmitted within the detection block, eliminating the need for isolators on internal paths and preventing propagation delay from affecting communication speed between the AFE circuit and control circuit.
Data Source
AI summary
A detection device includes: a sensor circuit; an AFE circuit configured to acquire a detection signal from the sensor circuit; a control circuit configured to control the AFE circuit; a reference potential generation circuit configured to operate with a first reference potential as a ground potential and generate a second reference potential synchronized with a square wave signal output from the AFE circuit; a first isolator provided on a transmission path for the square wave signal between the AFE circuit and the reference potential generation circuit; and a second isolator provided on a signal transmission path between an external processing device that operates with the first reference potential as the ground potential and the control circuit. The AFE circuit and the control circuit operate with the second reference potential as the ground potential, and signal transmission paths between the AFE circuit and the control circuit are electrically coupled.