Transimpedance Amplifier Overload Sensing for LiDAR Dynamic Range
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Solution Overview
Problem
Light detection and ranging systems face challenges in maintaining amplitude information of light pulses beyond the linear range of transimpedance amplifiers, leading to loss of data and signal integrity issues due to saturation, particularly in high current levels.
Innovation Solution
Incorporating an over-current sensing circuit with a clipping circuit and current scaling to generate an overload signal indicative of the amplitude of light pulses outside the linear range, allowing for the combination of output voltage and overload signal to provide high dynamic range processing in light detection and ranging receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the transimpedance amplifier operates in linear mode for a specific range of light power, then measurement precision is improved within that range, but loss of information occurs for light power outside that range due to saturation
Solution Approach 1:
The dynamic range is segmented into multiple regions: a linear region handled by the transimpedance amplifier and an overload region handled by the over-current sensing circuit. Each segment processes signals within its optimal range, preventing information loss while maintaining precision in the linear region
Solution Approach 2:
The over-current sensing circuit acts as an intermediary that captures and processes current information that would otherwise be lost during saturation events, providing a separate measurement path for high-intensity light signals
2Productivity
If the transimpedance amplifier processes high current levels, then productivity is improved by capturing more light signal, but reliability deteriorates due to saturation and signal integrity issues
Solution Approach 1:
The system uses feedback from the over-current sensing circuit to detect when the transimpedance amplifier is approaching or entering saturation, allowing the system to maintain reliability by switching to or combining with the overload signal path while preserving high current level information
3Loss of information
If the receiver captures light pulses with high amplitude, then loss of information is reduced by preserving amplitude data, but device complexity increases due to additional over-current sensing circuitry
Solution Approach 1:
The over-current sensing circuit extracts only the essential overload information needed to prevent data loss, separating this function from the main transimpedance amplifier path. This minimal extraction approach adds complexity only where necessary to capture amplitude information in saturation regions
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 solution enables the preservation of amplitude information even in saturated regions, enhancing signal integrity and object identification capabilities by providing a high dynamic range output that includes both linear and nonlinear current ranges.
Implementation Method 1
The optoelectrical device is configured to receive light and to convert the light to a current
Data Source
AI summary
Aspects of this disclosure relate to a receiver for a light detection and ranging system. The receiver includes a transimpedance amplifier that is operable in a linear mode for a range of power of light received by the receiver. The receiver can provide information about amplitude of the light outside of the range of power of the light for which the transimpedance amplifier operates in the linear mode. This information can be useful, for example, in identifying an object from which light received by the receiver was reflected.