Laser ranging systems are a widely used form of electronic system and are generally influenced by complex electromagnetic environments. We used a laser ranging system comprising the VL53L0X laser ranging sensor module as the research object and designed a sensitive experimental platform based on the laser ranging system. In this work, we have shown that electromagnetic interference signals can affect the performance of laser ranging systems. The electromagnetic interference signal was found to enter through the chip selection port of the laser sensor chip to affect the work of the laser sensor chip. Finally, we obtained the susceptibility threshold characteristics of the laser ranging system under the influence of different types of interference signal. This study deepens the understanding of the electromagnetic susceptibility mechanism of laser ranging systems and helps in the design of their electromagnetic compatibility.

Operational amplifiers (op-amps) are widely used in circuit systems. The increasing complexity of the power supply network has led to the susceptibility of the power supply port to electromagnetic interference (EMI) in circuit systems. Therefore, it is necessary to investigate the electromagnetic susceptibility (EMS) of op-amps at the power supply port. In this paper, we assessed the effect of EMI on the operational performance of op-amps through the power supply port by a bulk current injection (BCI) method. Firstly, we conducted the continuous sine wave into the power supply port by a current injection probe and measured the change in the offset voltage under EMI. Secondly, we proposed a new method of conducted susceptibility and obtained the susceptibility threshold regularities of the op-amps at the power supply port under the interference of different waveform signals. Our study provided conclusive evidence that EMI reduced the reliability of the op-amp by affecting the offset voltage of op-amps and demonstrated that the sensitivity type of op-amps was peak-sensitive at the power supply port. This study contributed to a deep understanding of the EMS mechanism and guided the design of electromagnetic compatibility (EMC) of op-amps.

Stepper motors, widely used for precise control in robotics and intelligent systems, are vulnerable to intentional electromagnetic interference (IEMI), which can disrupt their operation by affecting motor rotation. This article investigates the mechanisms and characteristics of the electromagnetic susceptibility (EMS) of a stepper motor control system to narrowband IEMI coupled through pulse signal lines. The bulk current injection method was employed, in which continuous wave (CW) and pulse modulation signals were used as the injected narrowband IEMI. The optocoupler (OC) at the drive subsystem interface was identified as the key component affecting the system's EMS, as confirmed through time- and frequency-domain experiments. The differential-mode IEMI activates the light-emitting diode in the OC, causing output logic disturbances that alter the number of driving pulses and ultimately influence the motor speed. Interestingly, at specific interference frequencies, the OC output logic level “1” is disturbed and drops to 0 V, whereas at other frequencies, the logic level “0” is disturbed and rises to 5 V. Under the CW injection, the stepper motor stops, whereas under the PM injection, the motor speed can be manipulated. The relationships between the PM signal parameters and the disturbed motor speed are modeled and experimentally validated. Finally, protection strategies were proposed and validated through experiments.

Differential driver chips enhance the signal quality and transmission efficiency in sensor systems, especially under challenging electromagnetic environments. This paper posits that different waveform interference signals, different disturbed ports, and different temperatures may compromise the electromagnetic susceptibility (EMS) of these chips, leading to phenomena such as latch-up, which results in abnormal VCC port currents and potential damage to the device. To validate this hypothesis, we proposed an innovative EMS testing method that utilizes signal characteristic sets to evaluate the effects of varying external temperatures, interference waveforms, and disturbed port conditions on the chip’s functionality. Our systematic experimentation reveals that external temperature variations exert a negligible influence on the EMS of these chips. In contrast, different interference signals and disturbed ports have a pronounced impact, significantly exacerbating the risk of abnormal currents. The results confirm our proposed hypothesis. This study lays the foundation for further optimization of the design of the differential driver and helps to improve the electromagnetic immunity performance of this type of device in the future.

This article develops a semianalytical model for characterizing the terminal responses of coated floating-ground multiconductor cables (FMCs) with arbitrarily routed wiring structures illuminated by a nonuniform electromagnetic field. In contrast to previous transmission line (TL) models, where only differential-mode (DM) coupling was considered, the proposed method decomposes the field-to-wire coupling effects in coated FMCs into common-mode (CM) coupling and DM coupling. First, for CM coupling, the coated FMCs are equivalent to a CM single conductor, and the CM current distribution along this conductor is obtained by full-wave simulations. Second, the equivalent coupled sources are decomposed into CM sources converted from the CM currents and DM sources induced by the electric and magnetic fields. The CM and DM sources are obtained separately by discretizing coated FMCs and sampling the incident electromagnetic field. Third, the combination model accounting for the comprehensive DM coupling is derived utilizing TL theory based on the equivalent coupled sources. The proposed method is validated through two application examples with good accuracy and higher computational efficiency compared with full-wave simulations.

An optocoupler is a widely used electrical control switching device that falls under the direct-current (DC) on/off category from a functional perspective. The datasheet for optocouplers typically provides DC characteristics and the delay time associated with the on/off switching transition. However, it often lacks detailed information regarding the device’s electromagnetic behavior and performance at radio frequencies (RF). To characterize the electromagnetic susceptibility (EMS) of optocouplers, we propose a new method that injects interference signals with different waveforms through direct power injection (DPI). This paper focuses on the EMS of two specific optocouplers, P521GB and PC817, which exhibit significant susceptibility to electromagnetic interference. The experimental results show that when the interference signal intensity exceeds the susceptibility threshold of the optocoupler, its operational state is altered, and the output voltage drops to a low level. Additionally, we present the susceptibility thresholds of the optocouplers under varying interference conditions. This study provides valuable insights into the electromagnetic susceptibility characteristics of optocouplers and offers data and theoretical support for the electromagnetic protection design of electronically controlled switching systems composed of optocouplers, which is of significant value.