HOW2POWER TODAY

ISSUE: February 2025

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IN THIS ISSUE:

» Snapback TVSs Deliver More Accurate And Robust Circuit Protection

» Designing An Open-Source Power Inverter (Part 24): Inverter Output Filter Conundrum

» Current Mode-Controlled DC-DC Regulators (Part 3): CC-CV Regulation

» Focus On Magnetics:
How To Model Coupled Inductors In A SEPIC Converter

» New on How2Power.com

» Power Products

» Other Top Power News

Some years ago we published a presentation by one of our contributors titled, “Surges and Transients Can’t Read Specifications! How to Protect Power Supplies Against Real-World Threats.” That humorous introduction to the subject of transient and surge immunity made the point that designers not only have to meet the relevant standards required for compliance, they often have to exceed those requirements in order to properly protect their electronic designs. Perhaps another takeaway from that document was that, within the reasonable limits of cost and other constraints, your circuit protection cannot be too robust because of the inherent unpredictability of electrical overstress events. The need for greater robustness is also driven by the increasing vulnerability of chips manufactured in advanced CMOS processes, and market pressures to make equipment more reliable. A feature in this issue by Kevin Parmenter looks at a newer class of overvoltage protection devices that offers more robust circuit protection by changing the way a TVS clamps a voltage transient. Kevin’s article on snapback TVSs explains how these devices provide more accurate protection as well as resilience in the face of repeated events. While such advances in circuit protection seem relatively infrequent, they are nonetheless vital to the success of many electronic designs and will always present opportunities for further improvement through the use of new materials, device design and packaging. This issue of How2Power Today also introduces articles discussing a unique dual-loop architecture that provides CC-CV regulation, output filter design for the open-source power inverter, and a guide to modeling coupled inductors in SEPIC converters. Enjoy these features along with the latest power product news and more in the February issue.

HOW2POWER EXCLUSIVE DESIGN ARTICLES

Snapback TVSs Deliver More Accurate And Robust Circuit Protection

by Kevin Parmenter, Taiwan Semiconductor, Brea, Calif.

In the rapidly advancing world of electronics, circuit protection is critical to ensuring equipment and system longevity, reliability, and safety. One of the latest innovations in this field is snapback TVS (transient voltage suppressor) technology. While no device is perfect for all applications, the advancement of snapback TVS technology brings the industry closer to the ideal solution for protecting many applications across various markets, including consumer electronics where warranty returns can consume entire profit margins. This article discusses the technology and market trends that are driving adoption of TVSs, the pros and cons of conventional TVS devices, and how snapback TVS device technology offers a groundbreaking approach to circuit protection. Read the article…

Unlike traditional TVS diodes which
simply clamp the voltage at a certain
threshold during a surge, a snapback
TVS reduces its clamping voltage once it
begins conducting.

The motivation for this modified
version of the L-C filter (with
uncoupled inductors) is explained
in this part.

Designing An Open-Source Power Inverter (Part 24): Inverter Output Filter Conundrum

by Dennis Feucht, Innovatia Laboratories, Cayo, Belize

As we approach the end of this Volksinverter design series, we address an aspect of power inverter performance that will be critical to commercial implementations of this design for compliance reasons as well as for the proper operation of the equipment being powered. The issue at hand is EMI, and specifically the conducted EMI produced by the inverter. The Volksinverter output stage—the inverter itself—has an LC filter. Will it adequately attenuate EMI currents? In this part we analyze operation of the LC filter, and discuss different possible solutions to suppression of common-mode currents, but ultimately settle on a modified configuration of the filter. We also analyze how PWM switching sequences affect EMI performance and which sequences are optimal. In the last section, filter design equations are presented. Read the article…

Current Mode-Controlled DC-DC Regulators (Part 3): CC-CV Regulation

by Timothy Hegarty, Texas Instruments, Phoenix, Ariz.

This article examines a constant-current, constant-voltage (CC-CV) dual-loop architecture for a dc-dc regulator that provides a constant output voltage or constant output current, depending on the application requirement and operating condition. The author outlines incumbent designs for the CC circuit that work as an add-on to a conventional dc-dc regulator. He then details a CC-CV integrated circuit (IC) approach with low external component count, reduced cost, accurate current-setpoint performance and improved transient response. The IC implementation is unique in that it selects the minimum of the currents from the transconductance error amplifiers in the CV and CC loops. This error current then flows in a shared compensation component network, the resultant compensation voltage becoming the reference command of the inner current loop of the current-mode architecture detailed in parts 1 and 2. Read the article…

An integrated solution for a CC-CV
buck regulator based on an enhanced
dual-loop architecture minimizes
interaction of the CV and CC loops,
achieving a clean transition from CV
to CC and vice versa.

FOCUS ON MAGNETICS       
Sponsored by Payton Planar Magnetics
A monthly column presenting information on power magnetics design, products, or related technology

How To Model Coupled Inductors In A SEPIC Converter

by Wei Gu, Analog Devices, San Jose, Calif.

Converter designs based on the single-ended primary inductance converter (SEPIC) topology often opt to use a coupled inductor both to reduce the number of components and overall converter size, and to simplify control. However, this design choice complicates simulation: If the coupled inductor is not modeled correctly, the simulated result can be quite different from the bench result. Unfortunately, there is not much guidance on this topic in the literature, particularly with regard to the SEPIC. This article discusses how to best model coupled inductors in a SEPIC design. Methods to build a proper model are introduced and the equations are included. Read the article…

NEW ON HOW2POWER.COM

Calendar of Events — Over 200 Listings For 2025

HOW2POWER’s Events Calendar lists selected conferences, tradeshows, workshops and webinars related directly or indirectly to power electronics. Our calendar currently lists over 200 of the electronics industry’s top events for 2025.
Visit this section …

POWER PRODUCTS

OTHER TOP POWER NEWS

In its 2025 predictions – GaN power semiconductors, Infineon highlights the ways in which gallium nitride will be a game-changing semiconductor material.

The EOS/ESD Association has released a new article to the ESDA website describing the importance, value and criticality of the ANSI/ESD S20.20 standard.

For those looking to present at ECCE 2025, March 2nd is the deadline for submissions of paper digests as well as proposals for special sessions and tutorials.