Hybrid Capacitive and Inductive Sensing Circuit for Compact Detection
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Solution Overview
Problem
Existing touch sensors require separate sense elements and circuits for capacitive and inductive sensing, making it costly and space-consuming to detect different types of objects, especially in small form factor devices.
Innovation Solution
A hybrid sensing circuit that can operate in both capacitive and inductive modes using a single sense unit, employing a signal generator and charge measurement circuit to measure capacitance and inductance, respectively, allowing detection of various objects using combined capacitive and inductive sensing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate sense elements and circuits are used for capacitive and inductive sensing, then detection capability for different object types is improved, but device cost and space requirements increase
Solution Approach 1:
The patent implements a universal sensing circuit that can operate in both capacitive and inductive sensing modes using a single sense unit. The circuit includes a signal generator that can output different signal types and a charge measurement circuit that can measure both capacitance and inductance parameters, allowing one circuit to perform multiple sensing functions that previously required separate dedicated circuits for each mode.
2Adaptability or versatility
If separate sense elements and circuits are used for capacitive and inductive sensing, then detection capability for different object types is improved, but device cost increases
Solution Approach 1:
The patent implements a universal sensing circuit that can operate in both capacitive and inductive sensing modes using a single sense unit. The circuit includes a signal generator that can output different signal types and a charge measurement circuit that can measure both capacitance and inductance parameters, allowing one circuit to perform multiple sensing functions that previously required separate dedicated circuits for each mode.
3Area of stationary object
If a hybrid sensing circuit is used for both capacitive and inductive sensing, then device space and cost are reduced, but circuit complexity increases
Solution Approach 1:
The patent employs dynamic configuration of the sensing circuit where the signal generator can switch between different signal types (capacitive or inductive) and the charge measurement circuit can dynamically adjust its measurement mode. This dynamic reconfigurability allows a single circuit to adapt to different sensing requirements, reducing the need for multiple fixed-function circuits while managing complexity through controlled flexibility.
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
Enables efficient detection of different types of objects, including ferrous and non-ferrous metals, within a single device form factor by sharing sensing components, reducing cost and space requirements.
Implementation Method 1
a first signal is applied to a sense unit and a second signal is measured on the sense unit in response to the first signal being applied to the sense unit, the second signal being representative of a capacitance of the sense unit
Implementation Method 2
a third signal is applied to the sense unit and a fourth signal is measured on the sense unit in response to the third signal being applied to the sense unit, the fourth signal being representative of an inductance of the sense unit
Data Source
AI summary
An apparatus for inductive sensing or capacitive sensing is described. The apparatus may include a signal generator to output on a first terminal a first signal in a first mode and a second signal in a second mode. The apparatus may include a charge measuring circuit to receive on a second terminal a third signal in the first mode and a fourth signal in the second mode. The third signal is representative of an inductance of a sense unit coupled between the first terminal and the second terminal. The fourth signal is representative of a capacitance of the sense unit.