15.5 An 800mW Fully Integrated Galvanic Isolated Power Transfer System Meeting CISPR 22 Class-B Emission Levels with 6dB Margin

Industrial field networks play a key role in industrial automation systems. Employing galvanic isolation in the transceivers of such networks has become an essential requisite to guarantee safety and better reliability in harsh industrial environment. For industrial transceivers, isolated power levels between 100mW and 1W are required. Transciever size and cost are also constrained in many industrial applications. However, delivering 100s of mW is challenging for fully integrated solutions without bulky external transformers, and it is also important to control radiated emissions at such power levels. In [1], [2], different ways of implementing fully integrated isolated power links have been proposed. However, they can only deliver 10s of mW, which limits them to low-power applications, e.g., sensor interfaces. Some of the state-of-the-art commercial devices use on-chip transformers made from thick gold traces to deliver 500mW at 33% efficiency [3], but a 4-layer PCB is required to implement a stitching capacitor across the isolation barrier to meet CISPR 22 Class B Electromagnetic Interference (EMI) standards [4]. ln this work, a fully integrated galvanic isolated power transfer system is proposed. By adopting various circuit techniques, 800mW output capability and 34% efficiency is achieved, and component-level emissions are kept low, eliminating the need for costly EMI-mitigation techniques and simplifying the EMI-certification process.