Galvo AFE Partitioning for LIDAR EMI Reduction
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Solution Overview
Problem
Conventional LIDAR systems face reduced accuracy and dynamic range due to electromagnetic interference (EMI) caused by routing high-impedance signals through connectors, which affects the galvo Analog Front-End (AFE) electronics used in frequency-modulated continuous-wave (FMCW) LIDAR systems.
Innovation Solution
The solution involves partitioning the front-end electronics to route low-impedance analog or digital signals directly on a small board mounted near the galvo, with outputs fed through the connector to the main board, using differential drive lines and controlling LED drive voltage and reference voltages to improve signal integrity and dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-impedance signals are routed through connectors in conventional LIDAR systems, then the system structure is simplified and easier to manufacture, but electromagnetic interference increases causing reduced accuracy and dynamic range
Solution Approach 1:
The system is divided into two separate circuit boards: a first circuit board containing sensitive analog front-end electronics (photodetector, transimpedance amplifier, common mode amplifier) and a second circuit board containing digital processing electronics. This segmentation isolates high-impedance analog signals from EMI-prone digital circuits and connector interfaces, thereby improving measurement precision while reducing electromagnetic interference exposure.
2Adaptability or versatility
If high-impedance signals are routed through connectors, then device complexity is reduced, but dynamic range is reduced due to EMI
Solution Approach 1:
The system is divided into two separate circuit boards: a first circuit board containing sensitive analog front-end electronics (photodetector, transimpedance amplifier, common mode amplifier) and a second circuit board containing digital processing electronics. This segmentation isolates high-impedance analog signals from EMI-prone digital circuits and connector interfaces, thereby improving measurement precision while reducing electromagnetic interference exposure.
Solution Approach 2:
The analog front-end section on the first circuit board is designed with specific local characteristics: high-impedance nodes are kept local and do not extend to connectors, differential signaling is used for position-sensitive detectors, and shielding is applied selectively around sensitive components. This localized optimization preserves dynamic range without requiring complete system redesign.
3Reliability
If high-impedance sense nodes are routed through connectors, then ease of manufacture is improved, but reliability is reduced due to EMI susceptibility
Solution Approach 1:
The system is divided into two separate circuit boards: a first circuit board containing sensitive analog front-end electronics (photodetector, transimpedance amplifier, common mode amplifier) and a second circuit board containing digital processing electronics. This segmentation isolates high-impedance analog signals from EMI-prone digital circuits and connector interfaces, thereby improving measurement precision while reducing electromagnetic interference exposure.
Solution Approach 2:
The high-impedance sense nodes are extracted from the connector interface entirely. The first circuit board processes analog signals locally and outputs only low-impedance differential signals through the connector to the second circuit board. This extraction eliminates the vulnerability of high-impedance nodes to EMI during connector routing while maintaining manufacturing simplicity.
Data Source
AI summary
A LIDAR system includes an actuator assembly and actuator position tracking circuitry. The actuator position tracking circuity includes a light emitting diode (LED) to emit a first signal toward an actuator, a photodiode to receive a second signal based on a position of the actuator and generate an output signal, and at least one front-end electronics to produce a low-impedance analog electrical signal based on the output signal.