Quantifying the performance of switch-mode power converters is an increasingly important aspect of system design. Systems are often required to meet standards for efficiency, standby power, power factor, harmonic distortion, and more. Switch-mode power converters have large capacitors connected to the ac input, resulting in complex input waveforms. Their performance cannot be analyzed correctly based […]
FAQ
Selecting dc-link capacitors for inverters
One key factor: Determining the nuances of how capacitors handle expected ripple currents. Sam G. Parler, Jr., P.E. Cornell Dubilier Examine a dc link capacitor’s ac ripple current and you’ll realize it arises from two main contributors: the incoming current from the energy source and the current drawn by the inverter. Of course, capacitors cannot […]
What is a “Joule Thief” dc/dc converter?
In some applications, it can be useful to drain almost all of the energy of a single cell battery, well below the voltage where the battery is usually considered fully discharged or “dead.” That’s when a Joule Thief dc/dc converter can be attractive. The name implies that the dc/dc converter is stealing Joules of energy […]
Fundamentals of fast chargers for phones and notebook PCs
Overlapping protocols and competing standards have created a confusing landscape for USB chargers. Here are the important differences and similarities of most interest to designers. Masashi Nogawa, Staff Systems Engineer Qorvo The first standard for charging via USB connections allowed power delivery at a 7.5-W maximum. Recently the USB standard jumped up to support 100 […]
No zapping! How to design safe and reliable wireless charging systems
Smart use of protection components can help give consumers a trouble-free charge. Todd Phillips Littelfuse Inc. The convenience that wireless charging systems provide has made them increasingly popular for use with consumer goods and appliances. But the development of wireless charging devices creates a number of challenges for designers. Most wireless applications are characterized by […]
How to boost output hold-up time in power supplies
Many supplies have outputs that don’t stay up long enough in the event of a power loss. Here are some ways to remedy the problem. TDK-Lambda Americas An ac-dc power supply’s input voltage can be interrupted during circumstances such as a brown out condition or a brief power failure. When this happens, the dc output […]
The advantages of Generation-Four SiC FETs
New silicon-carbide FETs perform better than previous versions and can replace silicon MOSFETs with relative ease. Anup Bhalla, VP Engineering UnitedSiC Wide-bandgap (WBG) semiconductors are now accepted as the future of high-efficiency power conversion. The reason: they provide lower conduction and switching losses than otherwise-comparable silicon-based IGBTs or MOSFETs. Since the introduction of WBG silicon […]
Maximizing the performance of SiC through gate drive techniques
New gate drivers simplify the task of deploying silicon-carbide FETs to shrink the size and boost the efficiency of power inverters. Charlie Ice Silicon Labs The electric vehicle revolution is upon us. Automotive companies search desperately for a technological edge, investors see EV companies as more valuable than traditional automakers, and governments press ahead with […]
Emerging applications for switched capacitor power conversion
Switched capacitor (SC) technology is often associated with on-chip filters and amplifiers or low-power and low-voltage power conversion such as charge pumps for wearables, Internet of Things (IoT) and similar battery-powered devices. That is changing. Today, SC power conversion is being developed for higher-power and higher-voltage industrial, electric vehicle and power grid applications such as […]
Handling the 48-to-12-V stepdown
A multiphase, interleaved buck converter can reduce bus voltage down to something useful in data center server racks. Brad Xiao, Nazzareno (Reno) Rossetti Maxim Integrated Hyperscale data centers that dissipate hundreds of megawatts demand efficient power delivery beyond the ability of the traditional 12-V power supplies on old server motherboards. A data center on 12 […]