Dual-Integrator Light Sensor Circuit for High Sensitivity
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Solution Overview
Problem
Conventional ambient light sensors lack the sensitivity required by modern electronic devices, resulting in inaccuracies between measured and real light intensity.
Innovation Solution
A high-sensitivity light sensor system comprising a light sensing element, integrators, comparators, reset circuits, counters, and timers that integrate and compare light currents to generate multiple sensing values, allowing for precise determination of light intensity through advanced signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ambient light sensor uses a photodiode and analog-to-digital converter, then the device complexity is low, but the measurement precision of light intensity is insufficient
Solution Approach 1:
The patent divides the light sensing process into multiple integration stages (first integrator and second integrator) with separate comparators and counters for each stage. This segmentation allows the system to process light intensity measurements in discrete steps, improving precision by capturing subtle variations that a single-stage system would miss, while managing complexity through modular circuit design
Solution Approach 2:
The patent transitions from a single-dimensional measurement approach to a multi-dimensional processing framework by implementing dual integration paths with different integration times. The first integrator uses a longer integration time for baseline measurements, while the second integrator uses a shorter integration time for dynamic changes, creating an additional temporal dimension that enhances measurement precision without proportionally increasing circuit complexity
2Reliability
If multiple integrators and comparators are added to improve sensitivity, then the measurement precision increases, but the device complexity increases
Solution Approach 1:
The patent implements multi-functionality by designing the first and second integrators to serve dual purposes: the first integrator processes both ambient light signals and backlight reflection signals, while the second integrator processes reflected light signals. The comparators and counters are reused across different measurement modes, reducing the need for entirely separate circuitry for each function and improving reliability through consistent processing architecture
Solution Approach 2:
The patent employs periodic action through timed integration cycles where the first integrator operates during a first time period for baseline establishment, and the second integrator operates during a second time period for dynamic measurement. This periodic operation allows the system to achieve high sensitivity through multiple measurement opportunities while managing complexity by reusing the same hardware components in alternating cycles
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
The system achieves more accurate and sensitive light measurement results, meeting the higher sensitivity demands of modern devices by effectively integrating and processing light signals.
Implementation Method 1
The light sensing element is configured to sense a light during a measurement time interval to generate a first current
Data Source
AI summary
A high-sensitivity light sensor includes a light sensing element, a first integrator, a comparator, and a second integrator. The light sensing element senses a light during a measurement time interval to generate a current. The first integrator integrates the current to generate a first integration signal. The comparator compares the first integration signal with a threshold value. While the first integration signal is greater than the threshold value, the comparison signal is at a first level. The second integrator is coupled to the first integrator and integrates the first integration signal to generate a second integration signal. The light sensor of the present invention uses two integrators to integrate the sensed voltage twice. Therefore, the light sensor of the present invention has a higher sensitivity.