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Nowadays, there is hardly anyone, who in their lives have not used a battery of some sort. To put it simply, a battery is a device which converts chemical energy to electricity. Rechargable batteries are a direct step up – their energy can be recharged and batteries used many times. SSB (Solid state battery) is a derivative of the conventional rechargable accumulator, which seems very promising in the field of IoT (Internet of Things) or even automobiles. CeraChargeTM (BCT1812M101AG) battery is a recent addition to the SSB family, and my bachelor thesis is a study on the properties this battery posseses, and if it is useful in practise. My scope of work consists of building a device, which can artificially raise the temperature as well as measure it, and also be capable of charging and discharging the battery. After that, I was able to test many different aspects. Mainly, charging/discharging using various modes and temperatures. Also, I tested how the accumulator woud fare at it’s operating temperature extremes, what would happen if the polarity was switched and measured the capacity of the battery. In order to acquire the test results, I used a DAQ (Data Acquisition) device USB-231, and a GPE (Graphical Programming Environment) LabVIEW to program the experiments. The results were mediocre – on one hand, the experiments were conducted successfully – battery efficiency tends to increase with every charge/discharge cycle and varies around 0,8, yet still far away from 0,95 efficiency that conventional lithium-ion batteries with a liquid electrolyte achieve. Battery capacity value was pretty close to what the manufacturer declared. Also, polarity change is techcnically possible, yet it worsens CeraCharge specifications a bit. Unfortunatelly, on the other hand, data analysis shows that CeraCharge suffers heavily from self-discharge and is practically unusable at specified temperature extremes.

The goal of this work is to review the most economical low power buck – boost converters that exist today, experimentally investigate the main electrical parameters of one of the best low power buck – boost converters Texas Instruments TPS63900 and evaluate its application in tandem with hybrid supercapacitor. An evaluation board with the converter was designed and after doing the research a few conclusions were made: the converter has shown efficiency levels not lower than 75% when load current was as low as 2 microamperes and efficiency levels, near 90% which were observed when operating in high load currents, when load current is greater than 20 microamperes. The converter is able to maintain its configured output voltage level in all recommended output current range with a 0,1 V precision. In boost mode when output current is in order of few hundred milliamperes the converter’s output voltage is maintained in pulses whose amplitude can reach 50 mV. Finally, in order to guarantee converter’s stable operation with high internal resistance power source, a high capacitance capacitor is required to be connected to converter’s input and a system which guarantees charging input capacitor to higher than converter’s start - up voltage level and then enabling the converter via its EN pin which is used for turning it on.

Capacitors are important passive electrical components. For this reason, the aim is to maximize the quality of these products and their resistance to environmental influence. Some of the main problems with capacitors are: the dependence of their capacitance on the charging voltage and the ambient temperature. The capacitance usually depends on the voltage and almost always decreases while increasing charging voltage. In addition, the capacitance of this type of capacitor is strongly dependant on temperature, charging time, current and frequency. Therefore, they are not recommended for use in circuits where linearity is required (sound equipment, measuring devices). Additionally, reduction in capacity at high voltages must also be taken into account regarding power circuits. The aim is to produce capacitors whose capacitance and temperature dependence would be minimal or at least the alterations in capacitance dependence on voltage would be inverse - the capacitance would increase with increasing voltage. This article introduces the research of a ceramic capacitor with a TDK manufactured dielectric perovskite strip. The aim of the research is to find out the behaviour of this capacitor using reverse voltage, to investigate the dependence of the capacitance of a ceramic capacitor on voltage and current and the dependence of the capacitance on temperature. Furthermore, evaluation of the aging properties of these capacitors is done. Firstly, a capacitance measurement model was constructed, which works in a wide range of voltages from 0 to 500 V and ensures a constant charge / discharge current of the capacitor. The suitability of this model for use in further testing was tested using a stapling capacitor. The capacitive dependencies of the test capacitor on the voltage and temperature, which correspond to the properties specified by the manufacturer, were measured. Capacitance-voltage dependency studies were carried out using three different discharge currents. Examination of the connection with opposite polarity showed that the capacitor irreversibly loses its capacitance due to the inverse voltage. Monitoring of the self-discharge rate showed that a voltage of opposite polarity connected to a capacitor with a perovskite dielectric permanently reduces the capacitance of this capacitor. In addition, such a violation significantly increases its leakage current, which is particularly strong at voltages

Investigation of Real-Time Clock Contribution to Microprocessor System Reliability

Robust Electrometric Amplifier As technology constantly evolves, so does electrometers. There is a need to achieve high sensitivity of this device as it is used in high variety of scientific experiments. To improve sensitivity various amplifiers are used with field effect tranzistors and currently the most popular of them is an operational amplifier with JFET tranzistors. However in modern electrometers with operational amplifiers they have two major flaws: high cost and sensitivity to electrostatic voltage. To develop the sensitivity most modern electrometer operational amplifier is with integrated guard buffer. I used ADA4530-1 type electrometer operational amplifier with is one of the first amplifiers in the world with integrated guard buffer. It is an operational amplifier designed to interface with the extremely high impedance sensors used in electrometer applications. The ADA4530-1 achieves extremely low input bias currents while simultaneously providing robust protection against ESD damage. A unique ESD diode structure provides protection while also allowing the diodes to be guarded to minimize leakage currents to the input pins. In this study the electrometer operational amplifier with integrated guard buffer was studied under various conditions to show device’s capabilities. First the device was tested with various impedance and capacitors to show basic voltage relaxation over time at 21 °C room temperature. Additional results were measured to show how the performance reacts to temperature change at 40 °C and 80°C. The results of these tests show that this specific electrometer is best used at temperature range between 21 and 30°C where output bias current is low and stable. To test capabilities of the guard buffer compared performance of diodes used in my electrometer and a JFET type transistor. The results showed that the JFET type transistor generates dangerously high input voltage at higher (for ex. 1-5kV ESD) input current which is significantly worse than the electrometer with integrated guard buffer. Additional study shows that the integrated guard buffer determines input impedance. It means that if a guard bias voltage is close to zero, then the whole device input impedance is determined only by the leakage of a plastic frame and input transistor. In other cases, as bias voltage of the guard amplifier gets higher, the impedance of an electrometer amplifier input becomes lower. It can be concluded that the electrometer with an ADA4530-1 type operational amplifier is highly resistant to ESD overloads and for this reason it is better than other electrometers with a traditional guard system.

The aim of this work was to explore characteristics and limitations of resonant inductive coupling wireless energy transfer system and to increase effective range of transfer. Two systems have been tested: first one had communication capabilities, second one hadn’t. First system consisted of transmitter with BQ500211 IC and receiver with BQ51013 IC. Communication between them was achieved using WPT Qi v1.01 standard, which was embedded into IC’s, and which were capable of autonomous power regulation between themselves. Research mainly focused on efficiency coefficient of the system and its characteristics in different environments and over different system configurations. The efficiency coefficient was calculated by using data of input power consumption of the transmitter and output power of the receiver. Also, the frequency of current which was applied into LC circuit was monitored for better understanding of how the system regulates power transfer. Also, transmitter and receiver were modified so the distance of the energy transfer would increase. It was determined, that transmitter achieves control of power output by changing frequency of current which is applied to its LC circuit. The further the frequency was set from the LC resonant frequency the less power was transmitted to the receiver, but the frequency never reach resonant frequency. Also, it was determined that foreign conductive object, that are placed between two coils, decrease efficiency coefficient, because they absorb magnetic field and produce eddy currents which result in heat generation. Three zones of typical frequency dependence of distance graph were determined: area where frequency didn’t change by increasing distance between coils, second area where frequency dropped when distance increased and third area, where frequency stood the same, while the distance increased, but efficiency coefficient decreased sharply. Maximum distance over which 10mW of energy was transfer have been increased up to 107mm.

Uninterruptible Power Supply with Supercapacitors

It was thought that CBRAM memory is one of the most perspective new memory types, which has the potential to surpass the most commonly used flash memory. That is because CBRAM memory is based on forming very small filaments in a dielectric material between two electrodes. These filaments can be formed in a very short time, in a couple of nano seconds and also they are very thin, a few nano meters wide. Because of that the writing speed of the memory should be very high as well as the density. A model was created so we could use both memories. A program has been written which allows us to determine the needed characteristics. The times at which the data is written in both memories and data writing cycles were measured. It was observed that in the CBRAM memory errors appear much sooner than in flash memory. The dependency between new errors appearing and data rewriting cycles was determined. Also it was observed that the errors can be fixed. The numbers of how many rewriting cycles must pass for the memory cell to be fixed was found. Its dependency with the number of how many times the memory cell was fixed has been determined. Lastly the energy used when writing data in was measured in both memory types. When these characteristics were compared it was observed that the amount of correct rewriting cycles in CBRAM memory is much lower than the amount of rewriting cycles in flash memory. In the start of the experiments CBRAM demonstrated much lower data writing times (15 times lower than in flash memory) this advantage soon disappears because at the moment when the first errors appeared this time started growing rapidly. Also it was measured that the energy used for data writing in CBRAM memory is 145 times lower than the energy used in flash memory. Considering these results it was concluded that CBRAM memory is not capable of replacing flash memory, at least at this time.

TOF Distance Meter VL53L0X Assay Vl53L0X is LIDAR (light detection and ranging) device that uses “Time of Flight” technology. Device is very small: 4,4mm length, 2,4mm wide and 1mm height and cheap so it can be useful almost everywhere where it needs to detect range to object. Main application for this device is user detection for computers, robotics, 1D gesture recognition, laser assisted autofucus. TOF technology is fairly simple- there is laser, photodetector and processor. At first, laser send one light pulse towards object and sends signal to processor. Then, light pulse reflects from the object and returns to photodetector which sends signal to processor. And then, processor calculates the time difference from when light pulse was sent and returned. And finally by knowing this time it can easily calculate range to object. The purpose of this investigation is to compare this device with most popular rangefinders and measure its parameters. Compared with other rangefinders VL53L0X is the cheapest and smallest but it has worst accuracy compared with other laser rangefinders. Also it has slower than other laser rangefinders. VL53L0X has a very complex programming and manufacturers does not provide necessary parameters to compile a program. Measured parameters shows that during some measurements accuracy was worse than 3 – 4 % that manufacturers give. Also its accuracy is very depended to environment light level. Because if measurements is being measured in environment where is a lot of infrared light accuracy drops a lot. In conclusion this device is the cheapest and the smallest of TOF rangefinders but it has quite bad accuracy. So this device can be used in when it is not necessary to be accurate and fast.

Research of Lithium–titanate (LTO) Battery's Properties Murata‘s UMAC040130A003TA01 energy storage device is a secondary lithium ion battery which combines beneficial features of both supercapacitor and lithium ion battery. Murata claims it can provide currents up to 10C and has a cycle number of up to thousands of times. Furthermore, its charge and discharge curves are that of a standard lithium ion battery and has a low equivalent series resistance (ESR). Meaning that this device can be used as a hybrid of lithium batteries and supercapacitors. The main task of this work is to test these claims - whether this battery really has such a low internal resistance, if its charge/discharge curves are that of a lithium battery and, finally, how does this UMAC‘s electrical characteristics change over high cycle numbers. To make it possible, a circuit designed specifically for these tests was used. The circuit can charge and discharge battery with a constant current set by microcontroller. Moreover, it can be set to ESR measurement mode and measure how battery’s voltage changes if an alternating load is applied at frequency of 1 kHz. Microcontroller makes measurements of battery voltage and then sends this data to a computer which can than plot charge/discharge curves, calculate capacity and internal resistance. The measurements showed that while the battery can indeed last many cycles, its 10C cycle is far too short. In addition, the measured ESR of UMAC proved to be almost tenfold the one claimed by Murata and this resistance is a function of load current, State of Charge (SOC) and the frequency of load. However, battery’s capacity is in compliance with Murata’s claims.

Impedance Meter with ADuCM350

Adjustable High Voltage Source

Wide Range Voltage Converter with Digital Control

Microprocessor-controlled Voltage Converter Working in the Optimal Load Principle Investigation

Magistro baigiamojo darbo tema – paskirstyta mikroprocesorinių valdiklių sistema. Šio darbo tikslas buvo suprojektuoti, trikdžiams atsparią, paskirstytų mikroprocesorinių valdiklių sistemą. Darbe apžvelgiamos mikroprocesorinių valdiklių duomenų perdavimo technologijos, mikroprocesoriniai valdikliai, mikroprocesorinių valdiklių sistemos. Darbo metu buvo suprojektuota ir pagaminta trikdžiams atspari mikroprocesorinių valdiklių sistema. Taip pat šiame darbe aprašomas paskirstytos mikroprocesorinių valdiklių sistemos mazgų programavimo procesas. Atlikus baigiamąjį magistro darbą gautos tokios išvados: perteklinių funkcijų panaudojimas, paskirstytų mikroprocesorinių valdiklių sistemų mazguose, padėjo padidinti tokios sistemos atsparumą trikdžiams bei užtikrinti stabilų sistemos darbą; paskirstytos mikroprocesorinių valdiklių sistemos be vedančiųjų mazgų pranašesnės už sistemas su vedančiuoju mazgu, tačiau tokioje sistemoje yra daug sudėtingiau užprogramuoti sistemos mazgus. Master‘s final thesis subject is distributed microcontrollers system. The objective point for this master thesis was to project fault tolerant distributed microcontrollers system. In master thesis overlooked microcontrollers data transfer technologies, microcontrollers and systems of microcontrollers. During this work was projected and made fault tolerant distributed microcontrollers system and programmed the nodes of this system. This master thesis conclusions are: redundant functions in the nodes of distributed microcontrollers system, helped to increase system stable and resistant; comparing the system without master nodes with system with master nodes, system without master nodes is more advantaged then system with them but this system programming process is more complicated.

Master‘s final thesis subject is distributed microcontrollers system. The objective point for this master thesis was to project fault tolerant distributed microcontrollers system. In master thesis overlooked microcontrollers data transfer technologies, microcontrollers and systems of microcontrollers. During this work was projected and made fault tolerant distributed microcontrollers system and programmed the nodes of this system. This master thesis conclusions are: redundant functions in the nodes of distributed microcontrollers system, helped to increase system stable and resistant; comparing the system without master nodes with system with master nodes, system without master nodes is more advantaged then system with them but this system programming process is more complicated.