Si un algorithme cryptographique peut être mathématiquement sûr, son implémentation matérielle quant à elle est souvent la cible de nombreuses attaques. Cette thèse porte sur l'étude des mécanismes d'injection de fautes pouvant permettre une cryptanalyse physique des circuits sécurisés et sur la conception de contre-mesures matérielles pour empêcher ces attaques.Dans un premier temps une mise en pratique d'injection de fautes sur une implémentation matérielle de l'AES a été menée à l'aide d'attaques physiques : variations statiques et dynamiques de la tension, de la fréquence, de la température et de l'environnement électromagnétique. La comparaison des fautes injectées nous a permis de conclure que ces différentes attaques partagent un mécanisme d'injection identique : la violation de contraintes temporelles.La conception et l'implémentation d'un voltmètre intégré nous a permis d'observer les perturbations internes dues aux attaques par variations transitoires de la tension. Ces observations ont permis une meilleure compréhension du mécanisme d'injection de fautes associé et une amélioration de la précision temporelle de ces injections.Ensuite, un détecteur a été implémenté et son efficacité face à des attaques électromagnétiques a été étudiée. Du fait de la localité spatiale de ces attaques, la zone effectivement protégée par le détecteur est limitée. Une implémentation de plusieurs détecteurs a été suggérée.Enfin, un nouveau chemin d'attaque exploitant la sensibilité du détecteur a été proposé et validé expérimentalement. / Even if a cryptographic algortihm could be mathematically secure, its physical implementation could be targeted by several attacks. This thesis focus on time-based fault injection mechanisms used for physical cryptanalysis of secure circuits.First, practical fault injections have been performed on a hardware AES implementation using non-invasive attacks : static and dynamic variations of the power supply voltage, frequency, temperature and electromagnetic environement. Then a comparison of these obtained faults led us to conclude that these different injection means share a common injection mecanism : timing constraints violations.An on-chip voltmeter has been designed and implemented to observe internal disturbences due to voltage glitchs. These observations led to a better understanding of the fault injection mecanism and to a better temporal accuracy.Then, a contermeasure has been designed and its effectiveness against electromagnetic attacks has been studied. Because of the electromagnetic pulses local effects, the aera effectively protected by the countermeasure is limited. The implementation of several countermeasures has been considered in order to extend the protected aera.Finally, a new attack path using the countermeasure detection threshold variations has been proposed and experimentaly validated. This attack exploit the electrical coupling between the AES and the coutnermeasure. Because of this coupling the countermeasure sensitivity variations are related to data handled by the AES.

This master‘s thesis deals with the design of battery powered soldering iron. The soldering iron will be placed in the plastic box from a conventional transformer soldering iron. First, we need to find the parameters of the original transformer soldering iron. Then design a synchronous step-down converter, driver of converter, BMS circuits, and component placement in a plastic box. The battery-powered soldering iron was successfully revived and tested, the final parameters of the converter are: voltage 0.4 V at 80 A current. The total power on the soldering wire is 32 W. Technically, this is a very interesting alternative to the classic version of the soldering iron, which can be used for assembly or repairs in poorly accessible locations.

This thesis focuses on optimization and increasing the efficiency of high-power DC/DC switching converters with transformer (switching power supplies). The work focuses mainly on using converters with flyback topology for high power, even though it is a common belief that this type of converter is not suitable for high power. This topology was selected because of potentially better achievable parameters, especially the efficiency, in comparison to a commonly used forward converter – in a flyback converter, losses are produced only in one magnetic component (transformer) in contrast to two components (transformer and inductor) in the forward converter. Compared to resonant and quasi-resonant converters, the flyback converter is easily controllable in the whole output voltage and current range. To make the flyback converter favorable for a high-power use, some innovative circuit modifications were made and modern semiconductor and passive components were used. Theoretical part of the work deals with efficiency optimization of the flyback converter, based on analytical solution. Operating parameters of the converter – switching frequency and parameters of the transformer (flux density and numbers of turns) are commonly only guessed or chosen from experience. The objective of this part is a mathematically exact determination of these parameters to achieve lowest total losses of the converter for given input parameters. In a certain case, it was possible to obtain the final solution analytically, in other cases the final solution step had to be done with a help of software. A prototype of a 12-kW switching power supply with a flyback converter was constructed to validate the proposed solutions and methods. The power supply fits into a space of only 33x33x16 cm. Modern semiconductors based on the silicon-carbide (SiC) technology (MOS-FET transistors and diodes) were used. After bringing the converter to a full-power operation, an efficiency of 96.8 % of the DC/DC converter was measured. High efficiency was obtained for a wide range of output parameters. A certain comparison with a forward converter with the same output parameters is done in the work. Not only from an efficiency point of view, the flyback converter seems very perspective.

This thesis deals with lead-acid battery, its parameters and temperature behaviour of this electro-chemical source of power. In the theory section, types of batteries are presented, followed by their primary parameters and electro-chemical reactions, which take part in battery cells. This section also contains information about charging stages, detailed description of each battery part, used materials, construction of the battery and degradation processes caused by battery operation. The practictal section of this thesis offers a measurement scheme for automated measuring workstation. Furthermore, the practical section presents results of measurements on parameters of chosen lead-acid battery types, it also contains long-term deep battery cycling and measurements under elevated temperatures. Detailed comparison of measurements results and datasheet values is included. Conclusion sums up parameters of chosen lead-acid battery types and their feasibility for further usage in power backuping.

The diploma thesis is focused on the building embedded demonstration application of the proprietary Low Complexity Ethernet module for industrial usage further called the LEN/LES 2. At the first, main used technologies such as MCU, or the lightweight IP stack is discussed, Consequently, there is detailed view on system hardware architecture proposed by hardware and software requirements. Then though part describes blocks of embedded system are in term of specific parts and hardware requirements to create universal board. Following chapters expresses first startup and known hardware bugs, LWIP implementation and MODBUS system implementation. The core of the system is the new released microcontroller an ADuCM4050 and the Low Complexity Ethernet MAC-PHY prototype block and much more dependent convenient peripherals of the MCU based application.

This diploma thesis deals with design of DC/DC converter which will be used in one-phase inverter powered from batteries. Required parameters are output power of 100 W, input voltage of 24 V and output voltage of 350 V. In the first part is briefly discussed used topology of flyback converter. In the next part is designed impulse transformer with a request to design impulse transformer as small as possible. Thesis continues with draft of power components placed on primary and secondary side of converter. In this thesis is part about limitation of voltage overshoot at turn off transistor. Next part of this thesis deals with the design of control circuits using an integrated circuit from the UC384x family. Thesis continues with the production and debugging of the converter. At the end of this thesis are measurements confirming the correctness of the proposed design.

This diploma thesis deals with analysis of function and subsequent construction of a quasi-resonant DC / DC converter 300 V / 50 V for an output of about 1.5 kW. The aim of this work is to test and describe the behavior of an experimental converter at various operating parameters. In the theoretical part, resonant circuits are described, as well as our connection of the resonant converter. Based on the used topology and the simulated behavior of the converter, the individual components of the power circuit and its control and excitation circuit are designed in Chapters 4 and 5. The sixth chapter deals with the construction and testing of the converter, including a description of its behavior. The last chapter contains technical documentation.

The following work deals with a design of power supply testbench with design of their replaceable modules and circuits for their measurement. The final product should be used for faster design and tuning of switching power supplies. In this essay, there is detailed description of switching power supplies, analysis of support circuits and calculations for design. Based on theoretical background and selected parameters, a connection concept will be created. This concept will be validated by a device that will consist of main board, changeable modules and measurement circuits.

This work deals with the design of a galvanically isolated converter of continuous analog signals and the design of a galvanically separated converter of digital TTL signals to HTL signals. The device is complemented by a STM32 microprocessor, which ensures the connection of analog input and output. The result of the work is the circuit structure of individual units, the results of simulations of important units, complete data for the production of device and measured values of individual units.

Presented thesis analyses a function of the particular type of the nanopositioner with aim to suggest and construct an electronic device suitable for control of the nanopositioner slider. In presented material there is a description of the control signals and possibility of their generating in the respect of slider movement accuracy. The main goal of the thesis is to describe electronic units ranging from power supply, control processor unit part to end part that directly joint nanopositioner. There is also programme equipment for microcontroller and computer, communication description, movement measuring and calibration and draft for the close-up of the control loop for additional increase of the movement accuracy.