Laurent Guillot

3D Electro-thermal modelling of bonding and metallization ageing effects for reliability improvement of power MOSFETs

Abstract This paper presents a methodology, based on 3D electro-thermal simulation, to investigate failures of vertical power MOSFET due to metallization ageing of source terminal. Modelling steps to obtain a 3D finite element modelling of MOSFET are presented with the smart approximations and limitations of MOSFET electrical behaviour. The effects of bonding wire gauge and contact area with top metallization are studied to optimize the power device design. The power device thermal runaway phenomenon and hot spot formation has been simulated and discussed.

Automotive Fan Control with Smart Power Switch [From Mind to Market]

This article presents a fan control unit requiring 30 A motor currents up to 20 kHz PWM. The smart integrated circuit (IC) used here includes a self-protected high-side switch with 4 mOmega RDSON, all digital control from a microcontroller, and extended diagnostics. High-current switching at high frequency generates electromagnetic interference (EMI) and power losses. Corner rounding and slew rates were optimized to reduce EMI filter size on the module. The power QFN (PQFN) package, half the size of the equivalent conventional package, helps to evacuate high power dissipation during switching. A smart power switch, combined with a 16-b microcontroller (MCU) and the control area network (CAN) communication protocol, provides an embedded solution, bringing cost savings on the system.