Dirk Ahlers

Repetitive avalanche of automotive MOSFETs

This paper will focus on one of the most difficult operation modes of automotive MOSFETs, the operation in avalanche in particular repetitive avalanche. Whereas single pulse avalanche conditions are typically very well defined and tested, repetitive avalanche operation is always an area of discussion as the number of influencing parameters is considerably higher. In automotive applications a vast range of requirements for repetitive avalanche are visible: starting from applications with only a very limited number of avalanche cycles however with comparably high energy, via applications which use the MOSFET avalanche capability on purpose to turn off inductive loads, towards applications switching the MOSFETs billions of times with very low avalanche energies. In this paper we discuss the requirements of repetitive Avalanche from application point of view, give some basic information on avalanche mode and test results of single and repetitive avalanche explained and assessed. Failure modes will be highlighted.

Relevance of P-Channel MOSFETs in Current and Future Applications

P-Channel MOSFETs are well known for their physical limitations compared to the N-Channel MOSFETs. Hole mobility is around three times smaller than electron mobility. Therefore a larger active area is necessary to achieve the same RDS(ON), thus making P-Channel devices more expensive. But they are equally known for their simplicity of usage. For applications in which a high side switch is needed, P-Channel MOSFET are the easiest option for their simple driver IC architecture and simple external circuitry, reducing the number of elements in the system. In this paper we will analyze the current and future usage of P-Channel MOSFETs.