<p>Switch Mode Power Supplies are very important components in present day electronics and have continued to thrive and grow over the past 25 years. This thesis looks inside how the SMPS have evolved over the passage of years with special emphasis to the Synchronous Buck Converter. It also discusses why there is a strong potential to further the study related to designs based around a Synchronous Buck Converter for portable applications. The main objective of the thesis is to look into the controller design for minimizing size, enhancing efficiency and reliability of power converters in portable electronic equipment such as mobile phones and PDAs. The thesis aims to achieve this using a 90 nm process with an input voltage of 1.55V and an output of 1V with a power dissipation of 200mW.</p>

Switch Mode Power Supplies are very important components in present day electronics and have continued to thrive and grow over the past 25 years. This thesis looks inside how the SMPS have evolved over the passage of years with special emphasis to the Synchronous Buck Converter. It also discusses why there is a strong potential to further the study related to designs based around a Synchronous Buck Converter for portable applications. The main objective of the thesis is to look into the controller design for minimizing size, enhancing efficiency and reliability of power converters in portable electronic equipment such as mobile phones and PDAs. The thesis aims to achieve this using a 90 nm process with an input voltage of 1.55V and an output of 1V with a power dissipation of 200mW.

This report is a study of the effects of a commercial 0.13[mu] process and automotive temperature corners on a synchronous DC-DC buck converter design. The basics of switching converters will be explored with an emphasis on voltage-mode controlled feedback. A Type-III compensation network is designed using transfer function analysis to compensate for the inherent double pole introduced by an LC network. The output of the compensation network will drive a pulse width modulation comparator to vary the duty cycle of the high-side PMOS and low-side NMOS transistor switches. After the synchronous buck converter design was complete, the effect of process and temperature on efficiency, output voltage ripple, inductor peak to peak current, and output voltage load response was examined. / text

abstract: Current sensing ability is one of the most desirable features of contemporary current or voltage mode controlled DC-DC converters. Current sensing can be used for over load protection, multi-stage converter load balancing, current-mode control, multi-phase converter current-sharing, load independent control, power efficiency improvement etc. There are handful existing approaches for current sensing such as external resistor sensing, triode mode current mirroring, observer sensing, Hall-Effect sensors, transformers, DC Resistance (DCR) sensing, Gm-C filter sensing etc. However, each method has one or more issues that prevent them from being successfully applied in DC-DC converter, e.g. low accuracy, discontinuous sensing nature, high sensitivity to switching noise, high cost, requirement of known external power filter components, bulky size, etc. In this dissertation, an offset-independent inductor Built-In Self Test (BIST) architecture is proposed which is able to measure the inductor inductance and DCR. The measured DCR enables the proposed continuous, lossless, average current sensing scheme. A digital Voltage Mode Control (VMC) DC-DC buck converter with the inductor BIST and current sensing architecture is designed, fabricated, and experimentally tested. The average measurement errors for inductance, DCR and current sensing are 2.1%, 3.6%, and 1.5% respectively. For the 3.5mm by 3.5mm die area, inductor BIST and current sensing circuits including related pins only consume 5.2% of the die area. BIST mode draws 40mA current for a maximum time period of 200us upon start-up and the continuous current sensing consumes about 400uA quiescent current. This buck converter utilizes an adaptive compensator. It could update compensator internally so that the overall system has a proper loop response for large range inductance and load current. Next, a digital Average Current Mode Control (ACMC) DC-DC buck converter with the proposed average current sensing circuits is designed and tested. To reduce chip area and power consumption, a 9 bits hybrid Digital Pulse Width Modulator (DPWM) which uses a Mixed-mode DLL (MDLL) is also proposed. The DC-DC converter has a maximum of 12V input, 1-11 V output range, and a maximum of 3W output power. The maximum error of one least significant bit (LSB) delay of the proposed DPWM is less than 1%. / Dissertation/Thesis / Ph.D. Electrical Engineering 2011

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The diploma thesis is describing how forward converter works. The diploma thesis presents the function of forward converter with demagnetizing winding and presents the function of two-switched forward converter. The diploma thesis descibes the behaviour of continuous current mode and discontinuous current mode. The diploma thesis explains the reasons for implementation feedback and presents the basic types of compensations. The project deals with AC analysis of two-switched forward converter with continuous peak current mode control. The Analog prototyping metod is used for digital control design. The function of the converter was tested in laboratory. The laboratory results have been compared with the theoretical and the simulation results.