Abstract
(Englisch)
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THE OBJECTIVE OF TERMIS WAS TO POINT OUT UNIQUE CHARACTERISTICS OF THIN-FILM SILICON-ON-INSULATOR (SOI) TECHNOLOGIES FOR HIGH-TEMPERATURE AND HIGH-VOLTAGE APPLICATION SPECIFIC INTEGRATED CIRCUITS (ASIC). THE DEMONSTRATOR AIMED BY THIS PROJECT IS AN ASIC TO DRIVE AN ELECTRICAL MOTOR DEDICATED TO AEROSPACE USE. THE TEMPERATURE AROUND THIS SYSTEM CAN REACH 225°C, WHICH IS VERY CHALLENGING FOR THE ELECTRONICS.ACHIEVEMENTSA CMOS SOI 1 MICRON PROCESS WITH HIGH-VOLTAGE MOS TRANSISTORS HAS BEEN DEVELOPED AND OPTIMIZED BY XFAB FOR HIGH TEMPERATURE APPLICATIONS. RELIABILITY IS IMPROVED BY USING TUNGSTEN METALLIZATION INSTEAD OF ALUMINUM IN ORDER TO AVOID ELECTROMIGRATION. A COMPUTER AIDED ENVIRONMENT FOR THIS PROCESS WAS ALSO PREPARED IN ORDER TO DESIGN CIRCUITS.EPFL HAS VALIDATED A DESIGN METHODOLOGY WHICH ENSURES THE PROPER OPERATION OF CIRCUITS IN THE TEMPERATURE RANGE OF -50°C TO 225°C. THIS METHODOLOGY INCLUDES GENERAL DESIGN RULES, METHODS FOR HAND CALCULATION OF CIRCUITS WHICH ALLOWS A BETTER UNDERSTANDING OF THE EFFECT OF TEMPERATURE AND SIMULATION BASED VERIFICATIONS. A LIBRARY OF BASIC BLOCS HAS BEEN CONSTITUTED: COMPARATORS, OPERATIONAL AMPLIFIERS, INTEGRATORS, PWM MODULATORS, A BAND-GAP VOLTAGE REFERENCE, AN A/D CONVERTER, FILTERS AND A HALL EFFECT SENSOR. THESE BLOCS HAVE BEEN INTEGRATED AND THEIR SILICON PROTOTYPES WERE CHARACTERIZED. A FIRST ASIC DESIGNED BY EPFL DRIVES THE 30 V, 1 A, 3 PHASES MOTOR. THE CIRCUIT CONTROLS THE TORQUE AND SPEED BY THE MEAN OF AN INTEGRATED CURRENT SENSING CIRCUIT AND A PHASE-LOCKED-LOOP (PLL). DESPITE THE LARGE TEMPERATURE VARIATIONS, THE CIRCUIT YIELD A FAST AND STABLE RESPONSE TO ANY MECHANICAL LOAD VARIATION OR SPEED SETTINGS. THE SPEED AND ANGLE FEEDBACK OF THE ROTOR IS ENSURED BY TWO MAGNETIC SENSORS, WHICH ARE THE OBJECT OF THE SECOND ASIC DEVELOPED AT EPFL. THIS ASIC COMPRISES A HALL PLATE, A REFERENCE, AMPLIFIERS, TEMPERATURE CORRECTIONS AND AN A/D CONVERTER ON A SINGLE SILICON DIE. ITS DIGITAL INTERFACE ALLOWS A HIGH LEVEL OF FUNCTIONALITY, SUCH AS SETTING OF MAGNETIC GAINS AND THRESHOLDS. THESE FEATURES ARE FOUND ONLY RECENTLY IN COMMERCIAL PRODUCTS. ITS ACCURACY IS ON PAR WITH INDUSTRIAL COMPONENTS, WHEREAS ITS TEMPERATURE RANGE EXTENDS FORM -50°C UP TO 270°C, WITH TOLERABLE PEAKS OF 320°C. EXISTING COMMERCIAL PRODUCTS OPERATE ONLY UP TO 160°C. APPLICATIONS OF THIS CIRCUIT EXTEND BEYOND THE FIELD OF AEROSPACE, AND THE AUTOMOTIVE INDUSTRY IS AMONG THE BIGGEST POTENTIAL USERS.CONCLUSIONPOTENTIAL ADVANTAGES OF SOI FOR HIGH TEMPERATURE APPLICATIONS WERE KNOWN FOR MORE THEN 20 YEARS. HOWEVER, UNTIL RECENTLY, INDUSTRIAL SILICON FOUNDRIES DID NOT OFFER SOI, WHICH HAS PREVENTED THE REALIZATION OF FULL SCALE CIRCUITS. THE TERMIS PROJECT HAS ACHIEVED TWO IMPORTANT GOALS: XFAB IS NOW ABLE TO OFFER A QUALIFIED SOI PROCESS TO CUSTOMERS, AND EPFL HAS DESIGNED CONVINCING ASIC DEMONSTRATORS.
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