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Design of ultrasonic receiver channel for automotive applications
Matějka, Alexandr ; Prokop, Roman (referee) ; Kledrowetz, Vilém (advisor)
This diploma thesis focuses on the design and characterization of an ultrasonic receiver channel for automotive applications. The main objectives of the thesis were to design low-noise preamplifier (LNA) and variable gain amplifier (VGA) circuits in the Cadence Virtuoso environment using the Spectre simulator. The circuits are implemented using onsemi's BCD65 technology. Parameters of the designed LNA circuit included noise referred to the input of 3.58 nV/Hz and a total gain of 44 dB at an operating frequency of 52 kHz. The VGA circuit was designed to allow dynamic gain switching with a step size of approximately 1.5 dB and to compensate for voltage asymmetry using a frequency-limited feedback transconductance amplifier. The gain of the VGA at control code 0 was -0.3 dB and at maximum code 31 was 45 dB. The resulting values met the given specifications. Circuit characterization was performed using Corner analysis, which included power supply variance, operating temperature, and process variation. Overall, the work provides a thorough theoretical and practical understanding of the subject matter with anticipated contributions to the field of automotive applications.
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Design of current sense comparators for automotive front lighting
Schilhab, Jan ; Prokop, Roman (referee) ; Kledrowetz, Vilém (advisor)
The diploma thesis deals with the problem of current sensing on integrated DC-DC converter switches using a comparator with reference current. Various current sensing methods are discussed in the thesis and a method of sensing current on a MOS switch using a smaller channel width reference transistor is thoroughly described. The paper also describes the basic properties of comparators and a suitable methodology for designing a fast comparator operating continuously in time. A major part of the thesis is devoted to the design of comparator blocks for current sensing at the top and bottom switches on the transistor level and presentation of the results obtained by simulations in Cadence Virtuoso environment. At the end, simulations are presented to verify the function of the designed blocks in a simplified buck DC-DC converter system.
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Design and implementation of a platform for control LLC-type inverter with a wide input supply voltage range using a FPGA circuit
Pokorný, Ondřej ; Levek, Vladimír (referee) ; Prokop, Roman (advisor)
This master’s thesis deals with the emulation of LLC converter control with a wide input voltage range using a created emulation platform. The first part of this work is focused on the design of resonant converters with a wide input voltage range. Based on theoretical knowledge, an adjustment of the emulation LLC converter is made. The converter modification is concluded with a simulation, where the correctness of the design and the fulfillment of the ZVS parameter in the entire input voltage range are verified. In the next part of the work, an analysis of the control issues of resonant converters, more precisely LLC type resonant converters, is carried out. The acquired knowledge is used for the design of a new emulation platform, which will serve for the emulation of LLC converter control with a wide input voltage range. The last part of the work is the creation of an emulation program for FPGA in SystemVerilog language. The work is concluded by verifying the functionality of the emulation on physical hardware.
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Design of a low-noise operational amplifier with 1/f noise analysis
Koukol, Martin ; Kledrowetz, Vilém (referee) ; Prokop, Roman (advisor)
This thesis is divided into two main parts. The first part deals with the physical description of the MOS transistor noise, focusing on the 1/f flicker noise. The equations for flicker noise in weak and strong inversion in linear and saturation regions and the dependence on transistor dimensions have been derived. These dependencies were verified by simulation. The second part deals with the design of a low-noise rail-to-rail operational amplifier, on which noise analysis was performer and also verified by simulation. The proposed operational amplifier was verified across process and temperature.
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Design of a chopper-stabilized multipath operational amplifier
Mrázek, Petr ; Kledrowetz, Vilém (referee) ; Prokop, Roman (advisor)
The main content of this work is the theoretical and practical design of the chosen topology of the chopper-stabilized operational amplifier. The introductory part of the diploma thesis focuses on the theory of noise, offset and drift. In other parts of the work, the origin of these phenomena and the possibility of their elimination are investigated. Furthermore, individual topologies are also analyzed in the work, from which one is chosen, which is then analyzed theoretically. Another part of this work is focused on the block design of the chopper-stabilized operational amplifier, from which the design of the entire system is subsequently created. The last part of the theory is focused on simulating the behavior of the designed chopper-stabilized operational amplifier and comparing it with the theoretical design.
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Curvature correction of the BandGap reference output voltage
Žeravík, František ; Háze, Jiří (referee) ; Prokop, Roman (advisor)
This thesis deals with the design of a Brokaw BandGap reference, a BandGap reference in a simple CMOS process, as well as the respective compensation circuits for correcting the curvature of the output voltage. In the theoretical part, the emphasis is mainly on describing the temperature dependency of the UBE voltage of the bipolar transistor and understanding the principle of the elementary BandGap reference. Based on these findings, the function and design of both BandGap references for an output voltage of 1.5 V are described. In the second part, the thesis focuses on describing various methods for correcting the curvature of the output voltage. Based on these methods, the first-order BandGap references supplemented with compensation circuits are designed. In the conclusion, the resulting parameters of the designed BandGap references without correction and with a compensation circuit are summarized and compared.
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Bulk-driven current mirrors
Kováčik, Martin ; Prokop, Roman (referee) ; Khateb, Fabian (advisor)
My bachelor’s thesis is about bulk-driven CMOS principle for several analog circuit projects. A substrate gate is used for signal input to achieve low supply voltage and low wattage while keeping parameters adequate to current structures. The goal of my work was to design current mirror with low supply voltage and low wattage with usage of this principle. In my work there are basic data about bulk-driven technology and MOFSET transistors used in this technology. My project contains different kinds of schemes of bulk-driven current mirrors which are compared with conventional gate-driven current mirror. These circuits are simulated in Orcard Pspise program.
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Design of low-voltage supply and reference block based on the bandgap reference
Mudroch, Michal ; Kledrowetz, Vilém (referee) ; Prokop, Roman (advisor)
In this diploma thesis there is elaborated design of low-voltage power supply block using I3T25 technology. The theoretical part describes the basic structures used in the design, using CMOS and bipolar devices. Furthermore, the properties and the analysis used in the evaluation are described. In the design part there is an elaborated design of individual parts, including voltage references, current references, DAC converter, operational amplifier. In the last part, the power supply block is subjected to simulations for verification of temperature compensated output variables and analyzed circuit functionality.
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