Photodetector Signal Level Estimation Without Per-Channel ADCs
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Solution Overview
Problem
LiDAR systems in autonomous vehicles require high-performance ADCs for each channel to handle the high-speed response of silicon photomultipliers, leading to increased power consumption and cost, which is not feasible for widespread adoption.
Innovation Solution
An apparatus and method for estimating the level of a signal output from a photo-detection device without an ADC, using a comparison device to vary a threshold voltage based on the output signal, allowing for accurate signal level estimation through a controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-performance ADCs are used for each channel to handle high-speed response of silicon photomultipliers, then signal level measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent extracts the ADC component from the signal processing chain and replaces it with a comparison device that uses threshold voltage comparison. This removes the power-consuming ADC while maintaining signal level measurement capability through binary comparison outputs.
Solution Approach 2:
The patent replaces expensive, power-intensive ADCs with simple, low-cost comparison devices that perform threshold voltage comparisons. This substitution dramatically reduces power consumption while preserving the essential function of signal level detection.
2Measurement precision
If high-performance ADCs are used for each channel to handle high-speed response of silicon photomultipliers, then signal level measurement precision is improved, but device cost increases
Solution Approach 1:
The patent replaces expensive ADCs with inexpensive comparison devices, directly reducing device cost. The comparison device architecture uses simple voltage thresholding instead of complex ADC circuitry, making the system economically viable for widespread deployment.
Solution Approach 2:
By removing the ADC component from each channel, the patent eliminates a major cost driver. The comparison device substitution reduces bill of materials cost and simplifies manufacturing while maintaining functional requirements.
3Measurement precision
If ADCs are used for each channel to identity signal levels, then target distinction capability is improved, but device complexity increases
Solution Approach 1:
The patent removes ADCs from the system architecture and replaces them with comparison devices. This extraction simplifies the device complexity while maintaining target distinction capability through binary comparison outputs that preserve signal level information.
Solution Approach 2:
The patent uses multiple comparison devices with different threshold voltages to create multiple binary representations of the same signal. This copying approach with varying thresholds enables reconstruction of signal level information without requiring complex ADC circuitry.
4Reliability
If multiple channels with ADCs are used to receive reflected light, then target detection capability is improved, but power consumption increases
Solution Approach 1:
The patent replaces power-intensive ADCs in each channel with low-power comparison devices. This substitution maintains multi-channel target detection capability while dramatically reducing the power consumption associated with high-speed ADC operations across multiple channels.
Solution Approach 2:
By removing ADCs from each detection channel and replacing them with comparison devices, the patent eliminates the primary source of power consumption in the signal processing chain while preserving the multi-channel architecture needed for reliable target detection.
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
Accurately estimates signal levels without the need for ADCs, reducing power consumption and cost, while maintaining the ability to distinguish targets based on reflectivity in LiDAR systems.
Implementation Method 1
a photo-detection device that outputs an electrical signal corresponding to an optical signal
Implementation Method 2
a comparison device for comparing a threshold voltage set by a controller with an electrical signal output from a photo-detection device
Data Source
AI summary
An apparatus for estimating a level of a signal output from a photo-detection device and a method therefor are provided. The apparatus includes a photo-detection device that outputs an electrical signal corresponding to an optical signal, a comparison device that outputs a high signal, when the electrical signal is greater than a threshold voltage, and outputs a low signal, when the electrical signal is not greater than the threshold voltage, and a controller that sets the threshold voltage, estimates a level of the electrical signal based on an output signal of the comparison device, and varies the threshold voltage based on the output signal of the comparison device, thus estimating the level of the electrical signal to have higher accuracy without having an ADC.