Shared Sample-and-Convert Capacitor for Low-Noise LiDAR Readout
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Solution Overview
Problem
Current LIDAR devices face challenges in accurately determining intensity levels of reflected light due to noise and circuit area constraints, as they typically require separate capacitors for sampling and holding data for conversion to digital data.
Innovation Solution
The proposed LIDAR detector and device incorporate a sample-and-convert circuit with a single capacitor that samples and holds the photodetector signal as a differential voltage, allowing for the same capacitor to be used for both functions, reducing noise and circuit area by maintaining a constant differential voltage across the capacitor, regardless of voltage changes on its plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate capacitors are used for sampling and holding data in LIDAR detectors, then the reliability of intensity level determination is improved, but the circuit area increases
Solution Approach 1:
The patent combines the sampling capacitor and holding capacitor into a single capacitor that performs both functions sequentially. The capacitor samples the photodetector signal during a sample mode and then holds the sampled value during a convert mode, eliminating the need for separate capacitors and reducing circuit area while maintaining measurement reliability.
Solution Approach 2:
The single capacitor is designed to perform multiple functions: it acts as a sampling capacitor during the sample mode and as a holding capacitor during the convert mode. This multi-functional design allows the same component to replace what would traditionally require two separate capacitors, thereby reducing circuit area without compromising the reliability of intensity level determination.
2Measurement precision
If separate capacitors are used for sampling and holding data in LIDAR detectors, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
By merging the sampling and holding functions into a single capacitor operated in different modes, the patent reduces the number of components and interconnections required. This simplification of the circuit architecture reduces device complexity while maintaining the measurement precision needed for accurate light intensity determination.
Solution Approach 2:
The capacitor's function dynamically changes between sample mode and convert mode. During sample mode, the capacitor is connected to the photodetector signal to capture the instantaneous value. During convert mode, the capacitor is isolated and holds the sampled value for conversion. This dynamic reconfiguration allows one capacitor to replace two static capacitors, reducing circuit complexity.
3Area of stationary object
If a single capacitor is used for both sampling and holding, then the circuit area is reduced, but noise may increase
Solution Approach 1:
The patent uses dynamic mode switching to isolate the capacitor from noise sources at different times. During sample mode, the capacitor is connected to the photodetector signal. During convert mode, the capacitor is isolated from the photodetector and connected to the comparator, preventing noise from affecting the held value. This temporal separation of connections minimizes noise interference despite using a single capacitor.
Solution Approach 2:
The circuit operates in periodic cycles alternating between sample mode and convert mode. This periodic switching ensures that the capacitor is only connected to potential noise sources (photodetector or comparator) during specific time intervals, allowing the held value to remain stable and noise-free during the convert phase when isolation is maintained.
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
This approach enables efficient sampling and conversion of light intensity levels, reducing noise and circuit area, thereby improving the accuracy and efficiency of LIDAR devices in determining environmental features.
Implementation Method 1
an input node to receive a photodetector signal
Data Source
AI summary
A LIDAR device includes an input node, an output node, and a sample-and-convert circuit. The input node receives a photodetector signal, and the output node generates an output signal indicating a light intensity value of the photodetector signal. The sample-and-convert circuit includes a number of detection channels coupled in parallel between the input node and the output node. In some aspects, each of the detection channels may be configured to sample a value of the photodetector signal during the sample mode and to hold the sampled value during the convert mode using a single capacitor.