EMC prilagojeno snovanje pretvornika DC-DC: Krmiljenje naklona preklopne napetosti

DIMITRIEVSKI, KRSTE (author), Žemva, Andrej (mentor), Subotskaya, Volha (comentor)

Namen magistrskega dela je predstaviti koncept prilagodljivega krmiljenja naklona preklopnnje napetosti v pretvorniku DC-DC in njegovo izvedbo v mešanem integriranem vezju. DC-DC pretvorniki postajajo vse pogostejši v SoC (System on Chip) aplikacijah zaradi njihovih lastnosti in zmogljivosti. DC-DC pretvorniki omogočajo visok izkoristek, majhno število zunanjih električnih komponent in potrebujejo majhno površino za realizacijo na čipu. Zaradi omenjenih karakteristik se vedno bolj uporabljajo v mnogih nizko-napetostnih SoC aplikacijah v avtomobilski industriji. Glavni cilj dela je bila realizacija pretvornika, ki omogoča adaptivno vodenje izhodne napetosti v celotnem obsegu DC-DC pretvornika. Pretvornik mora zagotavljati pravilno delovanje tudi pri uporabi zunanjih MOSFET tranzistorjev, ki prihajajo od različnih proizvajalcev. DC-DC pretvornik mora zagotoviti visoko frekvenco preklapljanja, če želimo doseči visok izkoristek, hkrati pa je potrebno zagotoviti, da elektromagnetne emisije (EME) ob preklopih ne presežejo zahtevanih ravni. Obstaja veliko različnih pristopov k reševanju tega problema. Za zmanšanje elektromagnetnih emisij lahko uporabimo EMI-ltre in posebne tehnike na PCB ravni. Naš cilj pa je bil zmanjšanje EME že v fazi načrtovanja integriranega vezja. Glavni poudarek magistrskega dela je raziskati koncept adaptivnega vodenja "gate" napetosti DC-DC buck pretvornika z različnimi zunanjimi MOSFET tranzistorji. Na podlagi zahtev bomo poziskusili doseči niske emisije že tekom načrtovalskega postopka z uporabo kombinacije analognih in digitalnih (AMS) vezij/tehnik. Končna resitev vsebuje kontrolno logiko, ki jo realizira digitalno vezje, in analogno vezje, ki vsebuje krmilnik "driver" in zakasnilno celico "analog delay". Vsebina magistrskega dela bo predstavljena v sledečem zaporedju. V prvem poglavju bomo predstavili concept EMC (Elektromagnetic compatibility) in razložili, zakaj je potrebno razviti proizvod, ki upošteva EMC predpise. Ravno tako bomo raziskali vzroke za nastanek elektromagnetnih emisij v integriranih vezjih, kjer bomo kot primer uporabili "switched mode power supply" aplikacijo, pod katero spada tudi DC-DC buck pretvornik. V drugem poglavju bomo predstavili dva koncepta, ki izpolnjujeta predhodno navedene zahteve. Končni koncept prilagodljivega goninlnika bo predstavljen v tretjem poglavju, kjer je kot vmesnik med kontrolnim blokom in prilagodljivim krmilnikom (driver), uporabljen napetostni preklopni "Level Shifter", ki prilagaja napetosti med krmilnim blokom in prilagodljivim krmilnikom. Predstavljeni bodo vsi izdelani bloki ter njhova funkcionalnost. Na koncu bodo predstavljeni spektralni diagrami elektromagnetnih emisij in primerjava emisij pretvornikov med adaptivnim in ksnim preklaplanjem. V zaključku sledijo ugotovitve in predstavitev smernic za nadaljnji razvoj.

• Language: Slovenian
• Keywords: EMC (Elektromagnetic compatibility), DC-DC pretvornik, sinhroni "buck" pretvornik, analogno nacrtovanje, EMI (Electromagnetne motnje), VHDL načrtovanje, SoC (Sistem na Čipu), EME (electromagnetne emisije), EMC predpisi
• Work type: Master's thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2017
• PID: 20.500.12556/RUL-105388
• Publication date in RUL: 23.11.2018

DIMITRIEVSKI, KRSTE, 2017, EMC prilagojeno snovanje pretvornika DC-DC: Krmiljenje naklona preklopne napetosti [online]. Master’s thesis. [Accessed 25 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=105388

Secondary language

• Language: English
• Title: EMC oriented design of DC-DC converter: Control techniques on the switching node slope

Abstract

The scope of this master thesis was to introduce and implement, a new concept for adaptive (dv/dt control) control of the slope of the switching node voltage in DC-DC Buck converter. The DC-DC Buck converter applications are becoming part of many SoC (System on Chip) applications because of their characteristics and performances. Some valuable features of the Buck converters are their high-efficiency factor, the small number of external electronic components and small area. The before mentioned features are the main reason why Synchronous Buck converters are used in many low-voltage automotive SoC applications. The main focus of this thesis was to create an adaptive control over the slope of the switching node voltage in DC-DC converter, which is using several types of external transistors from dierent vendors. The two main requirements were to keep the switching frequency high (in order to achieve high efficiency) and to reduce the conducted EME (Electromagnetic Emissions) generated from the switching activity of the Buck converter. There are many existing techniques for reducing the electromagnetic emissions like EMI-lters, special PCB design techniques etc., that can be used to minimize the EME of the power converter application, but in our approach our goal was to reduce the conducted EME during the design. The third important requirement was to have adjustable control driver that can control a synchronous DC-DC Buck converter which can use several dfferent types of the external MOSFET devices. This means that the control driver should work properly for all chosen external MOSFET devices. Considering the requirements we have implemented an adaptive driver control which should provide a reduction of the EME and improve the eciency. The solution presents a Mixed-Signal design. It employs a control logic, which needs to be implemented as a digital logic block, and an analog part, which needs to be implemented with programmable driver and analog delay block. The work of this master thesis is divided into several chapters. First, we will highlight some important topics from the EMC (Electromagnetic Compatibility) and why it is important to design a product that satisfies the international regulations concerning EMC standards. In Chapter 1 we will also explain what the sources of the Electromagnetic emissions in Integrated circuits are, especially in the Switched Mode Power Supply applications like Synchronous Buck converter. In Chapter 2, we will introduce two proposed concepts that were investigated in this master thesis work which full the given requirements. Also, some comparative analysis of the already existing concepts and the proposed ones will be given. Chapter 3 describes the implementation of the necessary blocks which are needed for the proposed concepts. The proposed concepts are consisting of Control Logic block and Adaptive Driver block. The connection between the control block and the adaptive driver is achieved with a Level Shifter which adapts the voltage levels between the control block and the adaptive driver. In this chapter, the implementation of the Adaptive driver block and Level Shifter block will be given. The implemented blocks will be presented together and their functionality will be checked in the concept's test bench. Out of the control block, an FSM (Final State Machine) state diagram will be created and presented here. It will be used in the future work for the Digital design. At the end of Chapter 3, the spectrum diagrams for the electromagnetic conducted emissions are presented. Some comparative analysis of adaptive switching mode (including the proposed concepts) and hard switching mode of the synchronous Buck converter were also given. At the end, the conclusions and further future work will be given.

• Keywords: EMC (Electromagnetic Compatibility), DC-DC Converters, Synchronous Buck converter, Analog design, EMI (Electromagnetic Interference), VHDL design, Verilog A, SoC (System On Chip) device, conducted EME (Electromagnetic Emissions), EMC regulations.