SAR ADC Dynamic Input Scaling for Touch Panel Power Reduction
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Solution Overview
Problem
Existing touch panels consume high power due to the energy requirements of analog-to-digital converters (ADCs), which limits battery life in portable devices and increases energy consumption.
Innovation Solution
Implementing successive approximation register (SAR) ADCs in multi-touch and proximity demodulation circuitry to detect touch or hover events on touch sensor panels, which consume less power and allow for dynamic input range scaling and offset adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional ADCs are used in touch panel receive channels, then conversion functionality is achieved, but power consumption increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the input range scaling and offset of the SAR ADC based on the characteristics of the touch panel signal. This allows the ADC to operate optimally across different signal conditions while maintaining conversion accuracy and minimizing power consumption through adaptive parameter adjustment rather than using a fixed high-power configuration
Solution Approach 2:
The patent implements dynamic input range scaling and offset adjustment mechanisms that adapt the ADC operation in real-time based on signal conditions. This dynamic adaptation allows the system to use lower power settings when appropriate while maintaining the necessary conversion functionality, directly addressing the power consumption issue
2Adaptability or versatility
If fixed input range ADCs are used, then circuit simplicity is maintained, but adaptability to different signal conditions deteriorates
Solution Approach 1:
The patent introduces dynamic input range scaling and offset adjustment capabilities to the SAR ADC, allowing it to adapt to different signal conditions. The system dynamically selects appropriate input ranges and offset values based on the detected signal characteristics, providing versatility without requiring multiple fixed ADC circuits
Solution Approach 2:
The patent creates a universal ADC circuit that can handle multiple signal conditions through dynamic parameter adjustment. The same SAR ADC circuit can adapt to different input ranges and offset requirements, making it versatile for various touch panel operating conditions while avoiding the need for multiple specialized ADC circuits
Data Source
AI summary
An apparatus for generating an image of touch on or about a touch-sensitive surface comprising a touch panel is disclosed. The touch panel can include a plurality of touch sensors configured for detecting one or more touch events occurring at distinct locations at about the same time. Each touch event can comprise a touching of an object against the touch-sensitive surface. A plurality of receive channels can be coupled to the touch panel for generating values representative of detected touch events. The receive channels can include a charge redistribution successive approximation register digital-to-analog converter (SAR ADC) configured to convert an analog waveform into a digital representation via a binary search and outputting the digital representation to an output register. The SAR ADC architecture can be such that it the dynamic input range can be scaled and offset adjusted.