Multi-Stimulus Touch Controller Phase Compensation Matrix
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Solution Overview
Problem
Conventional multi-stimulus touch controllers face inefficiencies due to phase delays in sense signals caused by varying signal path lengths, making it difficult to accurately process and compensate for these differences in multi-touch sensor systems.
Innovation Solution
A single-chip multi-touch controller is developed, incorporating a transmit oscillator, transmit and receive channels, and a demodulation section with a vector operator to generate and process drive signals, allowing for phase compensation of sense signals through a phase-compensated decode matrix, which accounts for individual phase delays in each drive and sense line pair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple drive lines are stimulated simultaneously to generate composite sense signals, then system productivity and processing speed are improved, but phase delays in sense signals are introduced due to varying signal path lengths
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing phase compensation values for each drive line in a lookup table before actual touch sensing operations. During operation, the system retrieves pre-computed phase correction data based on which drive lines are active, avoiding real-time phase calculation and enabling fast compensation without sacrificing measurement precision.
2Measurement precision
If phase compensation is implemented for each drive line, then measurement precision is improved, but device complexity increases due to additional processing requirements
Solution Approach 1:
The patent implements partial action by applying phase compensation only to the specific drive lines that are currently active in each sensing operation. Rather than continuously processing all possible drive lines, the system selectively compensates for phase delays in the subset of drive lines being used, reducing unnecessary computational overhead while maintaining measurement precision for active channels.
Solution Approach 2:
The patent uses copying by storing pre-computed phase compensation data in lookup tables that can be rapidly retrieved during sensing operations. Instead of recalculating phase compensation values in real-time, the system copies pre-prepared correction data from memory, significantly reducing processing complexity while maintaining accurate phase compensation for each drive line.
3Ease of manufacture
If conventional multi-stim systems are used, then ease of manufacture is maintained, but phase delay issues reduce processing efficiency
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the phase of sense signals based on pre-computed compensation values stored in lookup tables. The system modifies the phase parameter of received sense signals to counteract phase delays introduced by different signal path lengths, thereby improving processing efficiency without requiring complex hardware redesign or sacrificing manufacturing simplicity.
Data Source
AI summary
Determining a compensated phase matrix for a multi-stimulus demodulation process is provided. A first drive line of a multi-stimulus sensing system is selected, and a stimulation signal is transmitted on the selected drive line. A channel gain resulting from the stimulation signal is measured from a received sense signal resulting from the stimulation signal. The measured channel gain is compared with a known channel gain to obtain an individual phase compensation for the selected drive line. A compensated phase matrix is formed of the individual phase compensation values for multiple drive lines.