The AC/DC and DC/DC Books of Knowledge

Chapter 1: Power Regulation
This chapter is a comprehensive overview of DC/DC power supply topologies: linear and switching regulators, buck, boost and buck-boost converters and flyback, forward and push-pull topologies. If you want to know your SEPIC from your ZETA, you need to read this chapter!

Chapter 2: Feedback Loops
Feedback is the essence of every stable system. How can I design my analogue or digital power supply to react quickly to sudden changes in load or input voltage, but stay smooth when the load is constant? And why do I have to worry about my right half plane stability?

Chapter 3: Understanding Datasheet Parameters
If in doubt, read the datasheet! This chapter explains what all the parameters mean so your DC/DC design behaves the way you expect it to. What is the worst case performance I can expect?

Chapter 4: DC/DC Converter Protection
Prevention is better than cure. How to protect my DC/DC converter and how my DC/DC converter can protect my application. Read this or be sorry!

Chapter 5: Input and Output Filtering
Input and output filtering is one of the most important and most poorly understood aspects of any DC/DC converter design. Sort out your common mode from your differentials, and you don’t have to worry about your back ripple any more.

Chapter 6: Safety
Safety first. This chapter explains the hazards, risks and countermeasures that you need to know to make a safe design that meets the regulatory requirements. Get creepages and your clearances right and your design can pass the safety certification first time.

Chapter 7: Reliability
All manufacturers say that their product is reliable, but how do you design for high reliability? Find out which factors do the most harm to the lifetime of DC/DC converters.

Chapter 8: LED Characteristics
Power LEDs for lighting run best from a constant current supply, not a constant voltage. How do you protect your LEDs from being overdriven or over-heating? And which is better: Analogue or PWM dimming?

Chapter 9: DC/DC Application Ideas
This chapter is a collection of DC/DC tips and tricks that every designer might find useful: How can I double the output power? Can I connect DC/DC converters in series? How can I increase the isolation?

Chapter 10: Magnetics
The heart of a DC/DC converter is the magnetic component. This chapter takes you through the entire design process from choosing the right magnetic core and topology, to coping with the losses and handling the leakage inductances and capacitances.

Chapter 11: Advanced Assembly and Packaging
The new 3DPP^® chapter explores the different methods and techniques that have led to this paradigm shift. New packaging technologies have more than doubled the power density, so that a complete 15W converter in 3x3x1.5mm is now possible.

Chapter 1. A Historical Introduction
Have you ever wondered why we have 115VAC or 230VAC mains voltages, or 50Hz or 60Hz? Who chose these numbers, anyway? This chapter explains the history of the development of AC power.

Chapter 2: Linear AC/DC Power Supplies
Is there room for linear AC/DC power supplies in the modern world, or are switching power supplies the only answer?

Chapter 3: Apparent, Reactive and Active Power
Taking the analogy of a beer mug: active power is the liquid beer, reactive power is the head of foam and apparent power is the full glass. This chapter explains the mathematical relationship between “useable electricity” and “wasted electricity”.

Chapter 4: AC Theory
This chapter on AC theory covers impedance diagrams, phasors and the importance of the imaginary square root of minus one. What is the link between polarized light and Maxwell’s field equation?

Chapter 5: Passive Components
The working lifetime of a power supply is very often limited by the choice of capacitors. When is a 100µF capacitor not a 100µF capacitor? This chapter explains the stress factors and how to design an AC/DC converter with more than 20 years’ lifetime.

Chapter 6: Active Components
MosFET, IGBT, SiC or GaN? This chapter covers the fundamentals of power switching transistor behaviour and how to design for high reliability switching.

Chapter 7: Power Factor Correction
Power factor correction is often a regulatory requirement for AC/DC converters. What techniques are available and what are their respective advantages and disadvantages?

Chapter 8: AC/DC Converter Topologies
This chapter is a comprehensive overview of AC power supply topologies: single-ended, quasi-resonant, two-transistor, interleaved, parallel, half-bridge and full-bridge, single phase and three phase. If it is not here, you probably don’t need it!

Chapter 9: Transformerless AC Power supplies
Not all AC/DC power supplies need a transformer. What has IoT to do with non-isolated AC/DC converters?

Chapter 10: Wireless power
Power without wires has been an ambition since the time of Tesla. Now with the advent of Qi and other standards, wireless power is moving away from electric toothbrushes and becoming a very useful power transfer technique.

Chapter 11: Feedback
Feedback is the essence of every stable system. How can I design my power supply to react quickly to sudden changes in load or input voltage, but stay smooth when the load is constant? Why is the optocoupler the weak link in the chain and what alternatives to exist?

Chapter 12: Low Standby Power Consumption Techniques
Microprocessors have a current consumption that varies by a factor of 100million between full speed and deep sleep modes. How can I design my power supply to deliver full power when needed, but consume as little power as possible when the load is near to zero?

Chapter 13: Measuring AC
“Wer misst, misst Mist!“ Measuring AC is not so simple as measuring DC. This chapter outlines the different AC measurement techniques and explains why your multi-meter may not be telling you the whole truth.

Chapter 1: EMC Basics
This introductory chapter covers the concepts of electric, magnetic and electromagnetic fields, the fundamental maxwell equations, and how quickly electromagnetic waves move in different materials.

Chapter 2: Analysis
Building on chapter 1, this chapter explains the lumped circuit and skin effect models that can be used depending on wavelength to analyse circuit behaviour.

Chapter 3: Transmission Lines
At higher frequencies, EM waves move along conductors suffering from resonances, reflections, and standing wave effects. These phenomena can cause a significant deterioration in signal integrity and generate excessive radiated interference, so impedance matching may be required. Equally, correct matching is required for intentional PCB antennas for peak performance.

Chapter 4: EM coupling
This chapter covers the difference between near-field and far-fields and how these fields can couple across from a noise source to a victim circuit, along with different countermeasures that can be used to block the interference, whether it be capacitive, inductive, or galvanic coupling.

Chapter 5: Noise reduction techniques
Knowing which kind of noise interference (differential or common mode) allows the designer to identify the placement and type of noise filter that will be most effective.

Chapter 6: PCB Layout Impedance
PCB tracks and vias have an inherent DC resistance and AC impedance which will affect the flow of current in the circuit. This chapter details how to calculate these values to reach the required target impedance depending on the frequency of the signals used and introduces the concepts of the Fourier transform and harmonic spectra.

Chapter 7: Filters
Filters can be categorized by type, topology, grade, and mode of operation, so knowing which kind of filter will block or channel noise interference is crucial for a good design. This chapter also covers filter frequency and phase response (bode diagrams) and EMI countermeasures using filters and ferrite beads. This chapter also expands on the previous chapter to cover unintentional antennas and poor filter performance due to incorrect PCB layout.

Chapter 8: EMC standards
There are many technical standards that electronic circuits have to meet to pass the EMC regulations and the sheer number of them can be daunting. This chapter introduces the concepts of generic, basic, and product standards and goes through the most important ones, explaining what each standard covers depending on the required class and level, and how they are tested. It is important to know in advance which standard an application has to meet as compliance may mean physical changes to the PCB, changes to the design, or changes to the bill of materials.

Chapter 9: PFC
Power factor correction is an essential requirement for many power supplies and LED drivers. This chapter covers the basic terms (apparent, reactive and active power, and power factor) and the solutions that can be used for power factor correction and to limit THD.

Chapter 10: Measuring EMC
This chapter covers the equipment needed to test and measure products to check if they will meet the required EMC standard, including antennas, chambers, EM receivers, and LISNs.

An Introduction to the Fundamentals
The RECOM DC/DC Book of Knowledge course is the second course in this series, developed directly from the book.

The course provides a glimpse into fundamental concepts related to DC/DC power supply design, more detailed concepts can be found in the DC/DC Book of Knowledge. The course will cover key teachings such as SWaP factors, power regulators, feedback loops, DC/DC converter protection and how to interpret datasheet parameters.

An Introduction to the Fundamentals
The RECOM AC/DC book of knowledge is an extensive collection of experience and learnings necessary to implement successful AC/DC power supply designs. It is the culmination of many years of experience and numerous power supply designs from RECOM's technical guru and innovation manager, Steve Roberts.

This eLearning course is a quick overview of the book's content that you can complete in a matter of hours—as opposed to the many days (perhaps even weeks) necessary to comprehensively cover the book—so please consider this a preview of core concepts and teachings in the world of AC/DC power supply design.

Design for EMC
The EMC Book of Knowledge is the newest release in RECOM's Book of Knowledge series, covering critical experience and learnings necessary to successfully implement compliant power supply designs.

This eLearning course is a rapid-fire, basic overview of much of the book's content, previewing many core concepts and teachings in the world of power supply design, EMC design practices and EMI mitigation.