16 documents found, page 1 of 2
High precision, geometry independent analytical method for self-inductance calc...
Faria, Andreia Raquel Sampaio; Marques, L.; Ferreira, Carlos; Alves, Filipe Manuel Serra; Cabral, JorgeThis paper presents a versatile tool for the self-inductance calculation of planar coils. Due to the growing interest in planar coils in the past few years, the possibility of using an analytical model as a valid alternative to FEM simulations, regarding versatility and result reliability, would be of great interest. The ideal scenario would be to combine speed, precision, easy interaction and understanding, wh...
Technology independent ASIC based time to digital converter
Machado, Rui; Alves, Filipe Manuel Serra; Geraldes, Álvaro; Cabral, JorgeThis paper proposes a design methodology for a synthesizable, fully digital TDC architecture. The TDC was implemented using a hardware description language (HDL), which improves portability between platforms and technologies and significantly reduces design time. The proposed design flow is fully automated using TCL scripting and standard CAD tools configuration files. The TDC is based on a Tapped Delay Line ar...
Gray-code TDC with improved linearity and scalability for LiDAR applications
Machado, Rui; Alves, Filipe Manuel Serra; Cabral, JorgeThis paper presents a TDC architecture based on a gray code oscillator with improved linearity, for FPGA implementations. The proposed architecture introduces manual routing as a method to improve the TDC linearity and precision, by controlling the gray code oscillator Datapath, which also reduces the need for calibration mechanisms. Furthermore, the proposed manual routing procedure improves the performance ho...
Influence of mechanical stress in a packaged frequency-modulated MEMS accelerom...
Moreira, Eurico Esteves; Kuhlmann, Burkhard; Alves, Filipe Manuel Serra; Dias, Rosana Maria Alves; Cabral, Jorge; Gaspar, JoaoFrequency modulated accelerometers composed of two double-ended tuning fork (DETF) resonators on a differential configuration were characterized for their sensitivity to force applied to their package. Commonly, differential architectures are employed to cancel common mode errors, such as the mechanical stress or temperature dependency. The device dependence to mechanical stress was experimentally measured for ...
All-digital time-to-digital converter design methodology based on structured da...
Machado, Rui; Cabral, Jorge; Alves, Filipe Manuel SerraTime-to-Digital Converters (TDC) are popular circuits in many applications, where high resolution time measurements are required, for example, in Positron Emission Tomography (PET). Besides its resolution, the TDC's linearity is also an important performance indicator, therefore calibration circuits usually play an important role on TDCs architectures. This paper presents an all-digital TDC implemented using St...
Designing synchronizers for Nutt-TDCs
Machado, Rui; Cabral, Jorge; Alves, Filipe Manuel SerraApplications requiring both high resolution time measurement and large dynamic range demand for the integration of high-performance Time-to-Digital Converters (TDCs) and coarse counting methods which operate asynchronously. When using two asynchronous counting methods, the use of a synchronization mechanism is mandatory to correct metastability errors. Moreover, the placement and routing tools are designed and ...
Recent developments and challenges in FPGA-Based time-to-digital converters
Machado, Rui; Cabral, Jorge; Alves, Filipe Manuel SerraOver the past few years, the gap between field-programmable gate array (FPGA) and application-specific integrated circuit (ASIC) performance levels has been narrowed due to the constant development of FPGA technology. The high performance, together with the lower development costs and a shorter time to market, turns FPGA-based platforms attractive for a huge range of applications, among them time-To-digital con...
Auto-calibrated, thermal-compensated MEMS for smart inclinometers
Alves, Filipe Manuel SerraThe electronic control of a mechanical structure with micro dimensions, offers unique opportunities to exploit the tight coupling between co-integrated micromechanical structures and ICs (=Micro Electro Mechanical Systems (MEMS)). This coupling allows the implementation of integrated data-acquisition systems, with overall functionality or specifications that cannot be met using individually designed structures ...
Digital platform for wafer-level MEMS testing and characterization using electr...
Brito, Nuno André Mano; Ferreira, Carlos Daniel Araújo; Alves, Filipe Manuel Serra; Cabral, Jorge; Gaspar, João; Monteiro, João L.The uniqueness of microelectromechanical system (MEMS) devices, with their multiphysics characteristics, presents some limitations to the borrowed test methods from traditional integrated circuits (IC) manufacturing. Although some improvements have been performed, this specific area still lags behind when compared to the design and manufacturing competencies developed over the last decades by the IC industry. A...
Embedded platform for generic high-order sigma-delta accelerometers testing
Brito, Nuno André Mano; Lima, Vasco António Lourenço; Alves, Filipe Manuel Serra; Cabral, Jorge; Gaspar, J.; Monteiro, João L.The transition from an open loop to a closed loop sensing approach in MEMS accelerometers is an important step towards improving the sensor noise performance, bandwidth and time responses [1]. However, this approach presents some computational challenges due to the fast nature of the mechanical part, and ultimately, the performance of the feedback circuit will establish the sensor performance limits that can be...