Integrated Metal Shunt with Matched Sensing Resistor for High-Side Current Sensing

This article describes the design and implementation of an integrated metal shunt resistor matched with a sense resistor for a wireless charging system. The goal of the work was to create a $ 5m\Omega$ shunt resistor coupled to a 1k$\Omega$ sense resistor with a constant ratio of 1/200k over process and temperature variations. The article explains the challenges in designing the shunt and sense resistor using only metal layers and how the metal resistors were implemented.