Before we dive into specific application-based examples of noise and EMI mitigation, let's start with the basics. What is noise? What is EMI? What is ripple? How are they measured? What are some common approaches to limiting their effects? This section discusses these topics with a more conceptual approach to serve as a primer for the rest of the series.
Now that we understand the sources of EMI and noise in switching regulators, and some of the common approaches to mitigating each, let's take a closer look at real-world examples of reducing their effects. In this section we will examine the impacts of various mitigation techniques to help you decide which approach makes the most sense in your design. Techniques covered in this discussion include external component placement, filter options and design, frequency manipulation via spread spectrum or dithering, snubbers, boot resistors, and more.
Noise and EMI can be detrimental to sensitive analog signal chain circuitry. For this reason, many engineers automatically default to linear regulators. But, in doing so, they are essentially trading one problem (noise) for another (heat dissipation). In this section we will discuss what types of signal chain loads can be driven directly by a switching regulator to get low noise and EMI without sacrificing efficiency. We will also discuss when a linear regulator is absolutely needed to reach levels of noise not possible with a switcher.
Because of the potential havoc that interference can wreak in radio and safety critical systems, automotive electronics are subject to the most stringent EMI standards- the most common being CISPR25 Class-5. The materials below provide a discussion around the sources of EMI in an automotive environment and a comprehensive blueprint to understanding how to minimize it's effects.
Mitigating switching regulator EMI and noise is seen by engineers as a black art. Mess with the feng shui of the PCB layout too much, and the system may not pass CISPR standards. Because of this, many power designers simply turn to linear regulators as a guaranteed way to avoid the headache of reducing emissions.
This video series takes an in-depth look at voltage mode and current mode control in comparison to DCAP2 and DCAP3 control modes for step-down DC/DC converters.
Learn the features and benefits of TI's new DC/DC power topology, the series capacitor buck converter, and get started using it in your space-constrained design.
Control theory is often thought to be difficult to understand and theoretical approaches usually have lots of Mathematics and talk about Loop Gain, complex frequency, H(s), G(s) and so on.
Riding Out Automotive Transients : Architecting Front End Power Conversion Stage for Automotive Off-Battery Loads
With rapidly expanding electronic content in latest generation of cars, there is an ever increasing need for power conversion from the car battery rail. The 12-V battery rail is subject to a variety of transients. This presents a unique challenge in terms of the power architecture for off-battery systems. This presentation introduces the different types of transients that occur in automotive battery rails, the causes of those transients, and the standards and specifications defining the test conditions for those transients.
Learn about MicroSiP power module construction and how they have greatly increased the power density of power supplies over the years. See the evolution of discrete power converters to their MicroSiP power module counterparts. Specific comparisons and tradeoffs for the TPS82130, TPS82085, and TPS82671 are discussed.
Why should you understand power management?
In today’s computing environment, CPUs, FPGAs, ASICs and even peripherals are growing increasingly complex and, consequently, so do their power delivery requirements. To handle the higher demands, multiphase regulators are becoming increasingly common on motherboards in many areas of computing--from laptops and tablets to servers and Ethernet switches. Designing with these regulators is more challenging than using conventional switchers and linear regulators, but the benefits of multiphase outweigh the complexity for high-performance power applications.
The below introductory section features a video briefly discussing what exactly multi-phase buck regulators are, what applications they're suited for, and some of the challenges associated with implementing them. Additionally, the listed resources dive a little deeper into the topics covered in the video, providing further instruction in the beginning of your multiphase journey.