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CONCLUSIONS
In this thesis the platform oriented design of mixed-signal IPs for automotive application has been presented. The proposed platform based design approach has lead to the implementation of high performance platform for automotive sensors called ISIF. This single chip solution, implemented in a 0.35 um BCD technology, allows a fast prototyping of sensor interfaces, letting the designer the possibility to find the best conditioning architecture in a short time, thus improving time-to-market and final ASIC performances.
Details of the prototypization of a low-g dual axis accelerometer starting from the ISIF platform have been presented. The accelerometer features a ∆C variation of about 10 fF/g on Y axis while its rest value is 10 pF. The entire inertial system has been realized implementing a closed loop control on the Y axis thanks to the flexibility of hardware and software resources. The final prototype shows good performances featuring a 0.9 mg/√Hz noise density with 1024 LSB/g sensitivity on the digital output over a +/- 2g FS, and an average offset drift over 100°C range of 30 mg, with 2% of FS sensitivity drift.
Despite of these good performances, ISIF platform presents some fundamental limits. In fact the hardware platform has been developed using a leading-edge BCD integrated technology that guarantees reliability, high performances over temperature, ESD robustness and above all high gate density together with high voltage and high power devices. Anyway the platform has been limited to low voltage applications (5/3.3 V) since it was born to interface sensors such as last generation MEMS inertial sensors and MR sensors that can be actuated and sensed successfully with a low voltage level. Anyway high voltage and high power automotive electronics systems are widely used in automotive and they will gain much more importance in the next future with “X- by-wire” technologies and with upcoming tighten power saving requirements. For these reasons the PhD activities focused on the
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extension of the ISIF application space to high power automotive systems and to laser based video projection systems.
High power systems are quite often based on electric motor actuation. In this thesis the design, simulations and test results of a MOS half bridge driver featuring low ElectroMagnetic Interferences (EMIs) has been presented. The proposed solution has been designed for the new platform and consequently it features a high level of programmability in order to be utilizable in a wide range of applications depending on the frequency and on the power to be managed.
Laser based video projection systems are expected to find a wide utilization for the realization of new generation automotive head up displays thanks to the recent advance of Micro-Opto- Electromechanical Systems (MOEMS) and visible laser sources. The thesis has described in details this topic focusing especially on the state of the art of MOEMS and its actuators. Finally the design together with the simulation results of a scanning micromirrors high voltage driver in a 0.18 um BCD technology supplied by STMicroelectronics has been presented.
