Capacitive Hover Detection Circuit With Synchronized Reference Potential
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Solution Overview
Problem
Existing detecting devices face challenges in achieving accurate hover detection while maintaining a low cost and small size, particularly due to the need for insulating power and signal transmission paths to detection blocks.
Innovation Solution
The device employs a power supply circuit that generates a second reference potential fluctuating periodically, coupled with an AFE circuit to supply drive signals to sensor electrodes and acquire detection signals, using optical and magnetic isolation methods to isolate components, thereby reducing the size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ground potential of a detection block is set to a potential that fluctuates periodically in synchronization with detection signals and the shield electrode is supplied with this potential, then the accuracy in hover detection is improved, but the cost and size for electrically insulating power supply path and signal transmission path increase
Solution Approach 1:
The patent introduces a potential fluctuation synchronization circuit as an intermediary component that generates the fluctuating ground potential in sync with detection signals. This mediator enables the shield electrode to receive synchronized potential without requiring complex insulation structures, thus improving hover detection accuracy while controlling device complexity
Solution Approach 2:
The patent applies equipotentiality by making the ground potential of the detection block fluctuate in synchronization with the detection signals. This creates an equipotential environment between the detection block and shield electrode, reducing noise and improving measurement precision without requiring additional insulation mechanisms
2Measurement precision
If extensive electric insulation is implemented for power supply and signal transmission paths to achieve accurate hover detection, then measurement precision is improved, but device size and manufacturing cost increase
Solution Approach 1:
The patent merges the ground potential function with the detection signal fluctuation, eliminating the need for separate insulation structures. By combining these functions into a unified synchronized potential system, the device achieves accurate hover detection while reducing overall device size
Solution Approach 2:
The synchronization circuit acts as a compact intermediary that enables accurate potential management without requiring extensive insulation structures. This mediator reduces the volume needed for insulation while maintaining measurement precision
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
This configuration allows for accurate hover detection with reduced size and cost by isolating components effectively, enhancing signal integrity and noise reduction.
Implementation Method 1
a power supply circuit configured to generate a second reference potential that fluctuates periodically based on a first power supply potential that is substantially constant with respect to a first reference potential serving as a fixed potential
Implementation Method 2
an AFE circuit configured to supply a drive signal to the sensor electrodes, acquire a detection signal generated in the sensor electrodes
Implementation Method 3
Widely known are detecting devices that detect proximity of an object... includes a plurality of detection electrodes and a shield electrode disposed around a detection region
Data Source
AI summary
A detecting device includes a plurality of sensor electrodes provided to a detection region, a power supply circuit configured to generate a second reference potential that fluctuates periodically based on a first power supply potential that is substantially constant with respect to a first reference potential serving as a fixed potential and generate a second power supply potential that is substantially constant with respect to the second reference potential, and an AFE circuit configured to supply a drive signal to the sensor electrodes, acquire a detection signal generated in the sensor electrodes, and output a square wave signal in synchronization with the drive signal.