Hover Touch Circuit Using Dual-Reference Ground Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing capacitive touch detection technologies struggle with low precision in hovering touch operations when the distance between the user's finger and the touch electrode exceeds 5 mm, leading to ineffective touch detection.
Innovation Solution
The implementation of a dual-reference ground system where the touch detection drive circuit is isolated from a first reference ground of 0 V and connected to a second reference ground of 20 V, combined with an alternating current amplification circuit, to amplify the voltage difference for capacitive sensing, thereby increasing the detection range and signal-to-noise ratio for hovering touch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a larger distance between the finger and the touch electrode is used, then the detection range for hovering touch is increased, but the precision of touch detection deteriorates due to the smaller capacitor value
Solution Approach 1:
The patent changes the reference voltage parameter from traditional 0V ground to a raised reference voltage (e.g., 10V or higher) to amplify the capacitive sensing signal. This parameter change allows the system to maintain high measurement precision even when the finger is at a larger distance from the touch electrode, thereby resolving the contradiction between detection range and measurement precision.
2Length of stationary object
If the distance between the finger and the touch electrode is increased beyond 5 mm, then the detection range is expanded, but the capacitor value becomes too small for effective detection
Solution Approach 1:
The patent raises the reference voltage parameter to amplify the capacitive coupling effect between the finger and touch electrode. This allows reliable detection even when the distance exceeds 5 mm, as the enhanced voltage differential compensates for the reduced capacitance value, maintaining detection reliability across extended ranges.
3Device complexity
If traditional capacitive touch detection is used, then the system structure remains simple, but the detection precision deteriorates at distances greater than 5 mm
Solution Approach 1:
The patent modifies the electrical parameter (reference voltage level) rather than fundamentally changing the system structure. This approach maintains relative structural simplicity while dramatically improving measurement precision at distances beyond 5 mm through the enhanced voltage differential that amplifies the capacitive sensing signal.
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 approach allows for accurate touch detection at distances greater than 20 mm while maintaining precision, enhancing user comfort and reducing production costs by avoiding high-voltage requirements and electrode breakdowns.
Implementation Method 1
touch detection can be implemented by detecting a change of a capacitor formed when a touch electrode in the touchscreen approaches the finger of the user
Data Source
Figure 1~2B
Figure 3~4A
Figure 4B~5
AI summary
An electronic device, a control method for an electronic device, a touch system, and a chip system are disclosed, and relate to the field of touch technologies, to increase a detection range applicable to hovering touch. A touch detection drive circuit (20) in an electronic device (01) inputs a touch excitation signal (S1) to a touch electrode (10), and receives a detection signal of the touch electrode (10). An isolation power supply circuit (30) receives the touch excitation signal (S1) and a primary power supply voltage (Vin); based on the touch excitation signal (S1) in a non-touch detection phase (P2), short-circuits a first reference ground (GND 1) and a second reference ground (GND 2), stores the primary power supply voltage (Vin), and transmits the primary power supply voltage (Vin) to the touch detection drive circuit (20); and in a touch detection phase (Pl), disconnects the first reference ground (GND 1) from the second reference ground (GND 2) and discharges to the touch detection drive circuit (20). An alternating current amplification circuit (40) receives and amplifies the touch excitation signal (S 1) to generate a voltage regulation signal (S2), and transmits the voltage regulation signal (S2) to the second reference ground (GND 2). A peak-to-peak value of the voltage regulation signal (S2) is greater than a voltage value of the first reference ground (GND 1).