Magnetic field coupling on analog-to-digital converter from wireless power transfer system in automotive environment

There are multiple electrical devices on automotive system, which are control devices, communication devices, and digital devices. Each electrical device can generate magnetic field, one of the critical radiated electro-magnetic interference (EMI) elements. The operating frequency of each device is different and it means that the bandwidth of magnetic field is wide. Therefore, the strong magnetic fields can degrade the performance of diverse semiconductor systems in automotive applications, but it is not well discussed yet, even though the malfunction of electrical devices on automotive system is related to safe issues. So, we focus on strong magnetic field effects of semiconductor system. Among strong magnetic field source, we targeted wireless power transfer (WPT) system, which is spotlighted and promising technology for automotive and mobile charging system and significant magnetic field source. Furthermore, we choose analog-to-digital converter (ADC), sensitive to external noise and critical system involved in control devices related to the safety issues of automobile, as a targeted semiconductor system. In this paper, we discuss the magnetic coupling path and describe how to estimate the magnetic field effects on ADC with WPT. To estimate and analyze the targeted effects on ADC, we designed the ADC using a 0.13um CMOS process and WPT system using printed circuit board (PCB). Consequently, the magnetic field couples to ADC system, and there are three methods to estimate performance degradation of ADC by magnetic field effects, one is modeling, another is simulation, and the other is measurement.