Input Sensing Circuit with Shared ADC and Mode-Based Sampling
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Solution Overview
Problem
Existing input sensing devices face limitations in reducing the area of the input sensing circuit and unnecessary power consumption due to equal sampling rates and resolutions of analog-to-digital converters across different operating modes.
Innovation Solution
The input sensing device employs a multiplexer connected to multiple analog front ends and a single analog-to-digital converter, with varying sampling rates and resolutions in different operating modes, reducing the circuit area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the number of analog front ends and analog-to-digital converters equals the number of sensing signals, then the sensing capability is sufficient, but the area of the input sensing circuit cannot be reduced
Solution Approach 1:
Multiple analog front ends are merged to share a single analog-to-digital converter through the use of a multiplexer. The multiplexer sequentially connects different analog front ends to the same ADC, allowing the system to reduce the total number of ADCs while maintaining the capability to process signals from all sensing electrodes.
Solution Approach 2:
The analog-to-digital converter is made universal by enabling it to serve multiple analog front ends through time-division multiplexing. The same ADC resource is shared across different signal sources at different time intervals, making the converter multi-functional and reducing the overall component count.
2Use of energy by stationary object
If sampling rates and resolutions of the analog-to-digital converters are equal in one or more operating modes, then the sensing performance is consistent, but power consumption is unnecessarily increased
Solution Approach 1:
The sampling rate and resolution of the analog-to-digital converter are made dynamic and adjustable based on the operating mode. The system can switch between different sampling rates (e.g., first sampling rate in normal mode, second sampling rate in standby mode) and resolutions to match the current operational requirements, optimizing power consumption while maintaining adequate sensing performance.
Solution Approach 2:
The patent changes the operational parameters (sampling rate and resolution) of the analog-to-digital converter according to different operating modes. By adjusting these parameters dynamically - using higher sampling rates and resolutions when needed and lower ones when power saving is prioritized - the system adapts its performance characteristics to match the current operational context.
Data Source
AI summary
An input sensing device includes driving electrodes and sensing electrodes, analog front ends to process sensing signals provided from the sensing electrodes to output demodulation signals, a multiplexer connected to the analog front ends to select one of the demodulation signals, and an analog-to-digital converter to convert an analog output signal provided from the multiplexer into a digital sensing value. Sampling rates of the analog-to-digital converter may be different from each other in different operating modes. Resolutions of the analog-to-digital converter may be different in different operating modes. The input sensing device may be incorporated within a display device for displaying images.