Partner und Internationale Organisationen
(Englisch)
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Universita degli Studi di Pavia (I), SAIA Burgess Electronics Group, Murten (CH), Robert Seuffer GmbH & Co., Caiw (D), Austria Mikro Systeme Int. AG, Graz (A), CAEN Microelettronica, Viareggio (I)
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Abstract
(Englisch)
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The main goal of the MagIC project was to deliver packaged and tested evaluation samples of several specific CMOS integrated magnetic microsystems defined in response to market demands identified by the partner companies CAEN, SAIA, Seuffer, and Austria Mikro Systeme (AMS). The work was centered around the following demonstrators:
Rotation encoder based on magnetic integrated circuits for applications in automotive actuators, to be exploited mainly by SAIA. The need to introduce a new technology for smart actuator applications is dictated by SAIA's customers. Realistic market estimates indicate very high volumes for new markets within the next few years.
Programmable rotary switch based on integrated magnetic sensors for consumer applications, to be exploited mainly by Seuffer. A good knowledge of existing markets indicate high volumes.
Current monitor based on integrated magnetic sensors for commercial vehicles and high-voltage power supplies, to be exploited primarily by Seuffer (automotive market). For this device also, high volumes are anticipated in the medium term.
Three-dimensional magnetic badge to record exposure to magnetic fields based on integrated magnetic vector sensor, to be exploited primarily by CAEN. The targeted high-end product might be favored by legislation in the medium term. A substantial market volume is targeted.
AMS has identified a wider market for custom-specific integrated magnetic systems; therefore, AMS' 5 objective is to expand their design library accordingly to enhance wider exploitation.
SAIA's goal was to design a demonstrator of an encoder for applications in automotive actuators. In a first step, ETHZ designed a first sample sensor consisting only of an array of Hall elements. All necessary additional electronics for signal conditioning had to be included in the test and measurement system. AMS provided first samples of the sensor, which could be qualified in the labs of ETHZ. Based on those results, AMS designed and manufactured a second encoder sample. This sensor front end contained Hall Sensors and the necessary signal amplification and offset compensation circuitry. An additional digital circuit was designed to convert the encoder's Hall Voltages into a position information in a digital format.
In parallel SAIA redesigned it's demonstrator setup. This new setup provided better mechanical accuracy and better reproducibility of the results. The new sensor front end was tested and qualified using this second demonstrator setup.
In the last step SAIA redesigned an existing stepper motor actuator for automotive applications to be used together with the MagIC encoder. Additional electronics and a graphical interface were included in a separate device.
Using this complete evaluation sample, different functions of the actuator in the system could be evaluated and tested together with the customer. Based on those results customer requirements could be verified and had to be adapted partially.
Seuffer built up a demonstration board to test and present the rotary switch prototype samples. Several tests have been performed, including EMC investigations in collaboraton with ETH. Moreover theoretical and practical investigations about the shape of the permanent magnet have been done. Another test and demonstrator board has been developed for testing the current monitor prototype samples. Using this setup, final concentrator tests and system tests have been done.
In the frame of the MagIC project University of Pavia designed, characterized and supported the interface circuits for the rotary switch, current monitor and 3D badge demonstrators. The environmental prototypes of the interface circuits for the three demonstrator are fully functional within specifications. The basic analog and digital building blocks designed from University of Pavia for the MagIC demonstrators include an instrumentation amplifier, a programmable gain amplifier, a 12 bit successive approximation AID converter, a ratiometric incremental AID converter, voltage and current references, a window comparator, an 12S serial interface, a standard AID converter serial interface, and many other digital circuits. All of these blocks as well as the complete interface circuits have been integrated and successfully characterized.
ETH Zurich has developed in collaboration with AMS a novel vertical Trench-Hall device. In contrast to the well-known lateral Hall device, it is sensitive to components of the magnetic induction in parallel to the chip plane. This device allows a more accurate angle detection for rotary switch applications.
Moreover ETH Zurich improved the properties of magnetotransistors (MT's). This has been done by a comprehensive investigation of the causes of the offset. This lead to a deeper understanding of this phenomenon. As a consequence, new design rules could be created, leading to MT's with substantially reduced offsets.
ETH Zurich also performed 2D magnetostatic linear ANSYSTM simulations for Seuffer's current monitor demonstrator. This has been done in order to optimize the geometry of the current monitor sensor system. The simulatons show excellent agreement with experimental data for the standard system parameters.
During the whole project duration, ETH characterized the behaviour of almost all demonstrators and optimized the sensor parameters. ETH also performed EMC tests for the demonstrators and prototypes and organized two EMC seminars for the MagIC partners.
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