Efficient use of circuit & 3D-EM simulation to optimize the automotive Bulk Current Injection (BCI) performance of Ultrasonic Sensors

Ultrasonic sensors have a key role in the park assistance system and upcoming driver-assistance system concepts. Due to high sensitivity of receivers in ultrasonic sensors and strong bulk current injection (BCI) requirements of automotive Original Equipment manufacturers (OEMs), even low quality resonances in the receiver chain of the sensor could amplify the noise induced and may affect the sensor performance during component-level BCI tests according to ISO 11452-4 [1]. In this paper, resonances in the receiver chain and noise-coupling paths are analyzed by means of circuit spice simulation, 3D ElectroMagnetic (3D-EM) & circuit co-simulation and solutions are proposed. Effective use of simulation tools and the approach to start with the analysis is demonstrated in this paper. The simulation results correlates well with BCI pre-compliance test results performed in the semi-anechoic chamber. With this proposed approach described in this paper, influence of PCB & component optimizations in the next revisions of sensor can be anticipated and the BCI performance can be safeguarded.