30th Anniversary Section
This special edition of Power Electronics Technology celebrates the 30th anniversary of the magazine, which was originally published under the name Solid-State Power Conversion, and later as “Power Conversion and Intelligent Motion and as “PCIM Power Electronic Systems. In addition to commentaries from Ashok Bindra and David Morrison, this anniversary issue features a series of articles chronicling the developments that have taken place in the power electronics industry since 1975.
Top 30 Power Milestones and Products
A variety of developments in different fields have shaped power supply, power system, and motor control design over the past 30 years. Improvements in power component technologies and innovation in power electronics circuit design and simulation have advanced the state of the art. In this feature, contributing editor Randy Frank identifies the technological breakthroughs and landmark product introductions that enable us to measure the progress in the power electronics industry over the past three decades.
Top 30 Companies
Manufacturers of power supplies, power semiconductors, and other power components have shaped the development of power electronics technology, while building a multi-billion dollar industry that supports the rest of the electronics industry. Though dozens of companies have made worthy contributions to the field, in this article, contributing editor Randy Frank singles out 30 vendors and discusses their impact on the industry.
Looking into the Future
In previous issues of the magazine, contributing editors John Day, Steve Grossman and Gene Heftman discussed the 30-year evolution of passive components, magnetics, discrete power semiconductors, and power ICs. Picking up where those articles left off, this feature examines the technical trends that are expected to shape the power electronics field in the years to come.
Cover Story: Thermal Management
Power Semiconductors: The Influence of Parasitic Package Inductance on Efficiency
In dc-dc converter designs, thermally enhanced packages in SO-8 footprints have been gaining prominence and popularity. In addition to the electrical and thermal characteristics of the package, parasitic inductance also becomes critical. By John Lee, Vishay Siliconix, presents detailed experimental data on the parasitic inductance of two packages — the SO8 and the PPAK-SO8. The article examines the impact of these two packages on buck converter efficiency.
New Architectures Address Low Voltage Requirements In Networking and Telecom
The intermediate bus architecture (IBA) and the distributed power architecture (DPA) rely on a medium voltage bus that needs to be stepped down locally through point-of-load conversion. These architectures put a heavy demand on switching regulators to create low voltage supply rails (on the order of 1 V) with low output ripple. John McGinty, Micrel, discusses legacy solutions such as synchronous buck and multi-phase buck regulators as well as new architectures using high-speed post regulation to get the enhanced performance needed for powering modern digital processing cores.
Motor Power Management:
Thermal and Surge Considerations for Resistors in Motor Control Applications
Motor controllers, used to power, stop, and control the speed of a variety of motors, must deal with a wide variety of surges due to switching events. Power surge is a common cause of failure in resistors in motor control circuits. Many designers underestimate the potential for damage to resistors and other components resulting from the effects of power surge. David Winkler and Keith Chipman, IRC Wirewound and Film Technologies Division, describe surge conditions as they relate to motor power management, discuss the surge withstand capabilities of wire and film resistors, and design considerations when selecting these resistors for motor control applications.
A Method of Measuring the Input Current to a Buck or Flyback Converter
When designing power converters, it is often desirable to measure the dc current coming into the converter. This is particularly true when batteries are being used and the amount of discharge current out of the battery needs to be monitored and/or limited for the health and long-life of the battery. In most converters, there is a circuit that monitors the current through the main switch. This circuit is necessary to prevent damage to the switch under transient conditions for voltage-mode control and is an input to the control loop for currentmode control. John Bottrill, Texas Instruments, describes how this circuit may be used to measure the dc current flowing into the converter.