APD Quench Circuit Using a Discrete Transistor for Pulse Discrimination
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Solution Overview
Problem
Lidar systems face challenges in distinguishing between valid return pulses and anomalous pulses, such as crosstalk or jamming pulses, which can impact accuracy and reliability, especially in environments with interference or malicious attacks.
Innovation Solution
A circuit for quenching an avalanche photodiode (APD) detector is implemented, including a discrete transistor and an integrated circuit with comparators to control the reverse bias voltage, allowing for the differentiation of valid pulses from anomalous ones by comparing pulse characteristics and taking protective measures against jamming pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a discrete transistor is used to draw quench current for APD protection, then the reliability and protection capability are improved, but the device complexity increases
Solution Approach 1:
The quench circuit is divided into discrete components (transistor, resistors, capacitors) and integrated circuit elements, allowing the protection function to be separated from the main detector circuitry. This segmentation enables independent optimization of protection capabilities while managing overall system complexity.
Solution Approach 2:
The discrete transistor acts as an intermediary component that mediates between the control circuit and the APD detector. It provides a controlled path for quench current without requiring direct integration with the detector, thus improving protection reliability while maintaining manageable circuit complexity through wireless bonding or bump bonding connections.
2Manufacturing precision
If wire bonding or bump bonding is used to connect discrete transistor to integrated circuit, then the manufacturing precision and connection reliability are improved, but the manufacturing complexity increases
Solution Approach 1:
Wire bonding or bump bonding serves as an intermediary connection method between the discrete transistor and integrated circuit. This approach provides precise electrical connections without requiring direct monolithic integration, achieving high connection reliability while maintaining separate manufacturing processes for the discrete and integrated components.
Solution Approach 2:
The circuit is segmented into discrete transistor components and integrated circuit modules that can be manufactured separately using optimized processes, then connected through wire bonding or bump bonding. This segmentation allows each component to be manufactured with high precision using appropriate techniques while simplifying the overall manufacturing workflow.
3Measurement precision
If a capacitor is connected to the resistor to reduce noise, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
A capacitor is connected in parallel with the resistor to beforehand cushion or filter high-frequency noise signals. This RC filtering arrangement suppresses noise before it can significantly degrade the measurement signal, improving the signal-to-noise ratio while adding only a simple passive component to the circuit.
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 solution enhances the lidar system's ability to distinguish valid return pulses from anomalous ones, reducing susceptibility to interference and protecting the detector from damage, thereby improving accuracy and reliability in the presence of crosstalk or jamming pulses.
Implementation Method 1
avalanche photodiode (APD) detector
Data Source
AI summary
A circuit for quenching an avalanche photodiode (APD) detector is disclosed herein. The circuit may comprise a discrete transistor configured to draw a quench current so as to enable a drop in a reverse bias voltage applied to the APD detector, and an integrated circuit connected to the discrete transistor, the integrated circuit including a plurality of circuit elements for controlling the reverse bias voltage.