Laurent Beaurenaut

Short PWM Code: A Step towards Smarter Automotive Sensors

Digital sensors offer the possibility to increase globally the functionality of automotive systems and at the same time to further reduce their cost. The Single Edge Nibble Transmission (SENT) digital communication protocol is a promising low-cost solution for communication between sensor satellites and a microcontroller. This paper presents the Short PWM Code (SPC) protocol aiming at extending the SENT communication link in terms of functionality, performance and cost efficiency. SPC provides application relevant functionalities which are not included in SENT while still keeping as close as possible to the original protocol. In particular: bi-directionality, synchronicity and bus capability.

Optimized IGBT technology for mild hybrid vehicles

A new IGBT (Insulated-Gate Bipolar Transistor) technology with a blocking voltage capability of 400V was developed in order to further increase the improvements of hybrid vehicles in terms of fuel efficiency. Conduction and switching losses are significantly reduced by means of using an ultra-thin wafer technology (approximately 40μm thickness) having a direct impact on the overall efficiency. A complete inverter prototype was designed and used to compare the performance of state of the art 650V IGBTs and the new 400V technology. The results showed a significant decrease of the power losses using 400V IGBTs, which could be used to increase the efficiency (less fuel consumption), reduce cost (less chip area or cooling efforts) or/and increase the power density of the system (under same conditions, higher output power possible). Due to its reduced blocking voltage, this new IGBT is mostly suitable for mild hybrid vehicles with working voltages up to approximately 200V.