Modelling of current sharing in paralleled current limiting superjunction MOSFETs with common gate drives

This paper describes current sharing between paralleled MOSFETs having a common gate drive. This is important for situations where current needs to be controlled in the saturation region. A MOSFET model built in the Matlab toolbox Simulink is used to simulate the transient electrothermal behaviour of devices in order to evaluate the limitations of parallel MOSFET operation and determine if it is necessary to screen devices before using them in this particular application. First, several of the same MOSFET are characterised and their extracted parameters input into the computer model. The electrothermal behaviour of the devices is then simulated using a representative system model of a solid state current limiting switch. The results of these simulations are verified experimentally.