Low Voltage Power MOSFETs

Design, Performance and Applications

verfasst von: Jacek Korec

Verlag: Springer New York

Buchreihe : SpringerBriefs in Applied Sciences and Technology

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

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Über dieses Buch

Low Voltage Power MOSFETs focuses on the design of low voltage power MOSFETs and the relation between the device structure and the performance of a power MOSFET used as a switch in power management applications. This SpringerBriefs close the gap between detailed engineering reference books and the numerous technical papers on the subject of power MOSFETs. The material presented covers low voltage applications extending from battery operated portable electronics, through point of load converters, internet infrastructure, automotive applications, to personal computers and server computers. The issues treated in this volume are explained qualitatively using schematic illustrations, making the discussion easy to follow for all prospective readers.

Inhaltsverzeichnis

Frontmatter

Chapter 1. MOSFET Basics

Abstract

There is 90% chance that the reader can skip the 1st chapter as it covers just the basics of MOSFET structure and operation, along some examples of typical applications. Possibly the best approach is to have a glance at the figures and skip the text if the enclosed illustrations are well understood.

Jacek Korec

Chapter 2. Application Requirements

Abstract

The material presented in this script covers low voltage applications extending from battery operated portable electronics, through POL-converters (Point of Load), internet infrastructure, automotive applications, to PC’s and server computers. Thus, the switched current can be as low as hundreds of mA, or as high as 30 A per switch. The switched voltage can vary from 3 V for battery supply to 12 or 24 V as an intermediate voltage in power distributed systems. Even though the switched power varies respectively from 1 W to 1 kW, the application related issues have many commonalities. Just to stay focused, medium to high voltage applications have been excluded from the discussion.

Jacek Korec

Chapter 3. Power MOSFET Performance

Abstract

The first two chapters offered an introduction to power MOSFET fundamentals and described the expectation on MOSFET performance from the point of view of different applications. This chapter provides some basic hints how to make a good power MOSFET, especially one optimized for hard switching applications.

Jacek Korec

Chapter 4. MOSFET Generations

Abstract

The introduction of a new MOSFET generation on the market usually takes place in a situation when the previous generation has been there for many years and further incremental improvement of the technology doesn’t provide satisfactory improvement of the MOSFET performance. Figure 4.1 illustrates how the introduction of every new MOSFET generation in the past significantly improved the FOM. In marketing papers the transition steps are called technology breakthrough.

Jacek Korec

Chapter 5. Sync Buck Optimization

Abstract

This is the last chapter of the script discussing the ways how to take advantage of the improved performance of state-of-art MOSFETs as presented above. From the point of view of switching applications the most important improvement has been achieved by minimizing the switching power loss. Less switching loss allows an increase of the switching frequency of an SMPS unit, which in turn can be used to improve performance of the system as discussed in Section 2.2 and illustrated in Fig. 2.11.

Jacek Korec

Chapter 6. High Frequency Switching

Abstract

The meaning of the term high frequency switching as related to a synchronous buck converter applications depends on the power range, the step in the voltage conversion and the switching performance of MOSFETs used as power switches. In a power range of 1 W, and low input voltages, a switching frequency up to 10 MHz can be reasonably achieved. In contrast, switching 20 A from V_in of 12 V down to 1.2 V at a frequency of 2 MHz is a big hurdle if an efficiency close to 90% is expected. Switching power loss increases with output current and input voltage level, and is proportional to switching frequency. Respectively, novel, fast switching MOSFETs have to be used. On the other hand, 2 MHz frequency means a period of 500 ns only. If a duty cycle of 10% is required, the whole on-cycle has to be accomplished within 50 ns. This requires very effective and fast gate voltage control.

Jacek Korec

Backmatter

Titel: Low Voltage Power MOSFETs
verfasst von: Jacek Korec
Verlag: Springer New York
Electronic ISBN: 978-1-4419-9320-5
Print ISBN: 978-1-4419-9319-9
DOI: https://doi.org/10.1007/978-1-4419-9320-5