Adaptive Gain Light Sensor Circuit for Dynamic Ambient Adjustment
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Solution Overview
Problem
Existing light sensors face challenges in efficiently adjusting to varying ambient light intensities, leading to suboptimal power consumption and display brightness in consumer electronic devices, particularly in integrating ambient light and proximity sensors without compromising performance or increasing power usage.
Innovation Solution
A light sensor with an adaptively controlled gain, incorporating a photoelectric element, operational amplifier, comparator, adaptive gain control circuit, variable capacitor, and pulse accumulator circuit, which adjusts capacitance and current to optimize charging time based on light intensity, thereby enhancing light sensing efficiency and display brightness adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the light sensor uses a fixed gain structure, then the device complexity is low, but the light sensing efficiency and adaptability to varying ambient light intensities are insufficient
Solution Approach 1:
The patent implements dynamic gain adjustment by incorporating a variable capacitor whose capacitance can be modified according to ambient light intensity. The adaptive gain control circuit dynamically changes the capacitor's capacitance value to optimize the sensor's response characteristics for different lighting conditions, transforming a static system into a dynamic one that adapts to environmental changes.
Solution Approach 2:
The patent changes the physical parameter of capacitance in the feedback path of the operational amplifier. By varying the capacitance value of the variable capacitor based on ambient light intensity, the system modifies its gain characteristic to match different operating conditions, thereby improving sensing efficiency without requiring a completely complex redesign.
2Adaptability or versatility
If the light sensor adjusts gain dynamically, then the adaptability to varying light conditions is improved, but the device complexity increases
Solution Approach 1:
The adaptive gain control circuit operates autonomously by monitoring the ambient light intensity through the photoelectric element and automatically adjusting the variable capacitor's capacitance without external intervention. The system serves itself by using the sensor's own output to control its gain, eliminating the need for complex external control mechanisms.
Solution Approach 2:
The patent implements a feedback mechanism where the output signal from the photoelectric element is fed back through the variable capacitor to the operational amplifier. This feedback loop allows the system to continuously monitor light conditions and adjust its gain in real-time, improving adaptability while keeping the control logic simple and integrated within the sensor circuit itself.
3Measurement precision
If the sensor charging time is extended to improve measurement precision, then the measurement precision is improved, but the power consumption increases and usable time is reduced
Solution Approach 1:
The patent dynamically adjusts the charging time constant of the sensor by modifying the variable capacitor's capacitance in real-time. Under low light intensity conditions, the system extends the charging time to improve measurement precision. Under high light intensity conditions, it shortens the charging time to reduce power consumption, thereby optimizing the balance between precision and energy efficiency.
Solution Approach 2:
The patent changes the time constant parameter of the sensor circuit by varying the capacitance value. This parameter adjustment allows the system to optimize both measurement precision and power consumption according to ambient light conditions, resolving the contradiction between extending charging time for precision and reducing time for energy savings.
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 light sensor improves light sensing efficiency and accurately determines display screen resolution under varying light conditions, reducing power consumption and extending device usage time by dynamically adjusting to ambient light intensity.
Implementation Method 1
The photoelectric element is configured to convert light energy illuminating through the photoelectric element into a photocurrent
Data Source
AI summary
A light sensor having an adaptively controlled gain includes a photoelectric element, an operational amplifier, a comparator, an adaptive gain control circuit, a variable capacitor and a pulse accumulator circuit. The photoelectric element converts light energy into a photocurrent. The operational amplifier outputs an error amplified signal based on a gain multiplied by a voltage difference between an input voltage and a reference voltage. The comparator compares the error amplified signal with a voltage of a reference voltage source to output a comparison signal. The adaptive gain control circuit includes a pulse detector circuit and a gain control circuit. The pulse detector circuit detects the comparison signal and a clock signal to output a pulse detected signal. The adaptive gain control circuit outputs a capacitance modulating signal according to the pulse detected signal. A capacitance of the variable capacitor is modulated according to the capacitance modulating signal.