Application note on controling Intelligent Power Switches (IPS) from STMicroelectronics. Link here (PDF)
For the last 15-20 years, the automotive electronics market has been moving from electromechanical relays to solid state components for driving all kind of loads.
It is obvious why: solid state components are smaller in size, lighter, silent, easy to mass produce because they are housed in SMD packages, and they boast an unrivaled number of switching activations. On top of this, the solutions based on silicon components have a much higher electrical efficiency and offer useful types of diagnostics such as short-circuit, overload and thermal protections, they can supply an actual image of the current flowing into the load, and so on. In fact, they are called “Intelligent Power Switches (IPS)” or “Smart Power MOSFETs” for good reasons. The key “switching” element is an N-MOSFET, with the relevant charge pump. Around the N-MOSFET, logic interfaces and other elements contribute to the protection of the MOS and they generate and manage diagnostic data.