Innovative Smart Switch Architecture Catering to 12 Volts to 48 Volts Battery Bus Requirements

Electronics is rapidly entering all automotive subsystems, performing control and monitoring tasks apart from making the entire vehicle intelligent.. Interface with the external automotive ecosystem needs careful attention during the system design. It defines how seamlessly the electronic unit interacts with the rest of the vehicle. It needs to do so in an effective manner without compromising on cost and other automotive application constraints. This paper focuses on the “ smart switch building block” that forms the heart of an automotive output interface echo system. Its importance stems from the fact that a smart switch is an indispensable building block for any electronic control system driving external loads. As various novel electrical and electronics architectures are entering various vehicle segments need for a single reusable solution that will cater to 12 Volts to 48 Volts battery buses is increasingly being felt. However, no prevalent solution meets this requirement. Even for 12-volt and 24-volt buses, different solutions are required. Other areas where the existing solutions need improvement are ease of hardware and software interface, apart from a lack of robust short-circuit protections. The diagnostic architecture of currently available smart switch solutions adds to the complexity of the interface for interpreting malfunctions. This paper proposes a novel architecture that attempts to address all these shortcomings. The proposed architecture revolves around a robustly selected power switching element that is able to latch the CPU command. This significantly reduces the number of CPU pins. The concept design is illustrated by presenting a smart low-side relay drive switch architecture. The architecture is cleverly structured so that the same does not require external protections for transients. The future roadmap is discussed at the end.