Currently Intelligent Power Switch (IPS) is substituting the fuse and relay in automotive electronic systems due to its simplicity in design, assembly, and maintenance as well as its advantages of cost reduction. As the percentage of IPS in automotive power system gets higher, the stability and credibility of the automotive power system depends more by IPS evaluation. Since IPS is semiconductor device, the performance is more influenced by its ambient temperature than replacing fuses and relays. As reliability is one of the most important characteristics in automotive system, wire protection, over-current protection, and short-circuit protection should be considered. The evaluation algorithm of IPS must include these characteristics.
This paper describes the algorithm development of effective IPS (Intelligent Power Switch) evaluation software for automotive applications. The algorithm is fast and straightforward by adopting I-t characteristic of IPS, loads, and wires rather than time-domain simulation. The items included in the evaluation algorithms are load drivability, wire protection, over-current protection, and short-circuit protection. The algorithms consider worst case conditions imposed by temperature changes and differences which can occur in automotive environment. It is also possible to find way to improve the IPS based power distribution system from the evaluation result.