Touch Sensor Electrode Charge Recovery Circuit
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Solution Overview
Problem
Electrical circuits, such as touch sensors, lose significant charge during transitions between high and low reference voltages, leading to inefficiencies and increased power consumption, especially in designs with high capacitive loads.
Innovation Solution
Implementing a charge capture and re-use system where non-measured electrodes in touch sensors are connected to a capacitor coupled to a lower reference voltage before being connected to ground, allowing stored charge to be reused in other circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrodes are pulsed between high and low reference voltages at high frequency, then touch sensing capability is improved, but charge loss increases significantly
Solution Approach 1:
The patent converts the harmful charge loss during voltage transitions into a beneficial resource by capturing the discharged charge through a capacitor and reusing it for subsequent electrode pulsing operations. The charge that would normally be wasted during the transition from high to low reference voltage is instead stored and reused, transforming energy loss into energy recovery.
Solution Approach 2:
The patent implements a charge recovery mechanism where the charge discharged from electrodes during voltage transitions is captured and stored in a capacitor rather than being discarded. This recovered charge is then reused to power subsequent electrode pulsing operations, reducing the need for fresh charge from the power supply and thereby reducing overall power consumption.
2Adaptability or versatility
If the difference between high and low reference voltages is increased, then touch sensing range is improved, but charge loss increases
Solution Approach 1:
The patent transforms the increased charge loss resulting from larger voltage differences into a recoverable resource. By implementing charge capture circuitry that specifically targets the larger discharge currents generated by high-voltage-difference pulsing, the system recovers the excess charge that would otherwise be wasted, allowing the system to maintain large voltage swings for extended sensing range while recovering the associated energy cost.
3Measurement precision
If electrodes with large capacitance are used, then touch sensing sensitivity is improved, but charge loss increases
Solution Approach 1:
The patent implements a charge recovery system specifically tailored for high-capacitance electrodes. The capacitor in the recovery circuit is sized and configured to capture the larger charge quantities discharged by high-capacitance electrodes during voltage transitions. This recovered charge is then reused to replenish the electrode capacitance, reducing the net charge loss despite the larger absolute charge movements required for high-sensitivity sensing.
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 reduces charge loss during transitions, conserves power, and enables the reuse of captured charge for other components, thereby enhancing the overall efficiency of touch sensor systems.
Implementation Method 1
connect a second portion of the plurality of electrodes to a capacitor coupled to a third reference voltage
Data Source
AI summary
In one embodiment, an apparatus includes a first electrode, one or more processors, and one or more memory units coupled to the one or more processors. The one or more memory units collectively store logic that is configured to cause the one or more processors to control connections of the first electrode by connecting the first electrode to a first reference voltage, then connecting the first electrode to a second reference voltage lower than the first reference voltage, and then connecting the first electrode to a third reference voltage lower than the first reference voltage and the second reference voltage. The second reference voltage is coupled to a capacitor.