Under what conditions are power MOSFETs linear?

Mostafa Khoshnoud¹ Alireza Samadi²

1) Electronic Engineering Department,Chamran Univercity,Guilan.Iran
2) Student of Electronic Engineering,Chamran Univercity,Guilan.Iran

Publication : International Conference on Recent Advances in Engineering, Innovation and Technology - Belgium(eitconf.com/1st)
Abstract :
In most of cases, Power MOSFETs are used in switching operating conditions where RDS(on) is the key parameter to evaluate the device’s performance. However, in some special cases, devices work in linear zone. A Power MOSFET works in linear zone when high-currents and high voltages are together applied to MOSFET terminals. Power MOSFETs are used in linear zone in some dedicated applications especially in automotive segment such as: standard topologies of audio amplifiers, linear DC-DC converters, DC fan controllers, electronic loads, current mirrors, smart fuses, etc… In many of these applications, typically, the LV Power MOSFETs are used. Furthermore, Power MOSFETs work in linear zone for a short period of time when they are used in switching conditions during the Miller region where high-currents and high voltages are together applied to MOSFET terminals. This means that the thermal instability must be also evaluated in applications where linear zone isn t the typical operating condition. Therefore, this phenomenon needs to be evaluated even during the slow switching process either in LV or, in particular, in HV Power MOSFETs when high inductive loads are driven. Considering a theoretical Power MOSFET FBSOA, linear zone is referred to that area delimited by maximum allowed dissipated power duration.
Keywords : power mosfet linear Non Linear integrated circuit