Touch Panel Control Circuit Dynamic Switching for EMI and Power
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Solution Overview
Problem
Conventional electronic devices with touch functions suffer from high electromagnetic interference (EMI) and increased power consumption due to constant driving signals used for touch sensing, regardless of operation mode.
Innovation Solution
The electronic device incorporates a touch panel with sensing lines and electrodes connected through a control circuit featuring a first switch circuit that dynamically switches between electrical connection and disconnection of sensing lines, allowing for different touch sensing modes (standby and normal) to optimize power usage and reduce EMI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If driving signals with the same frequency or amplitude are used to drive sensing electrodes for touch sensing operations, then touch sensing performance is maintained, but electromagnetic interference (EMI) energy and power consumption increase
Solution Approach 1:
The patent applies dynamics by making the touch sensing system adaptable to different operation modes. The control circuit dynamically adjusts the driving signal characteristics (frequency or amplitude) based on whether a touch event is detected. In normal mode, standard driving signals maintain full touch sensing performance, while in idle mode, reduced driving signals lower power consumption and EMI. This dynamic adaptation resolves the contradiction between maintaining performance and reducing energy use.
Solution Approach 2:
The patent changes the parameters of the driving signals (frequency or amplitude) depending on the operation mode. By modifying these physical parameters of the driving signals, the system achieves different performance levels: full performance in normal mode with standard parameters, and energy-saving mode in idle mode with reduced parameters. This directly addresses the contradiction by allowing parameter variation to balance performance and power consumption.
2Reliability
If driving signals with the same frequency or amplitude are used to drive sensing electrodes for touch sensing operations, then touch sensing performance is maintained, but electromagnetic interference (EMI) energy increases
Solution Approach 1:
The system dynamically adjusts driving signal characteristics based on operation mode. During idle periods, the control circuit reduces driving signal frequency or amplitude, which directly lowers EMI energy while maintaining adequate touch sensing capability. When touch events occur, the system transitions to normal mode with full-strength signals to ensure reliable detection. This dynamic behavior resolves the contradiction between performance and EMI reduction.
Solution Approach 2:
The patent implements periodic scanning of the touch panel, alternating between idle mode (reduced driving signals) and normal mode (full driving signals) based on detected touch events. This periodic switching between operational states allows the system to minimize EMI during non-touch periods while ensuring full performance when needed, effectively resolving the EMI-performance contradiction.
Data Source
AI summary
An electronic device is provided. The electronic device includes a touch panel and a control circuit. The touch panel includes a plurality of sensing lines and a plurality of sensing electrodes. The sensing electrodes are coupled to corresponding sensing lines. The control circuit is coupled to the touch panel through the sensing line. The control circuit includes a first switch circuit. The first switch circuit is configured to control whether at least two sensing lines of the plurality of sensing lines are electrically connected. In the first mode, the first switch circuit electrically connects at least two sensing lines. In the second mode, the first switch circuit electrically disconnects at least two sensing lines.