Proposed solutions for achieving LTE-Advanced performance targets for the radio interface are defined in 3GPP TR 36.814, “Further Advancements for E-UTRA Physical Layer Aspects.” More...
The third generation of cellular radio technology was defined by the ITU-R through the International Mobile Telecommunications 2000 project (IMT-2000). The requirements for IMT-2000, defined in 1997, were expressed only in terms of peak user data rates. More...
LTE-Advanced (LTE-A) is the project name of the evolved version of LTE that is being developed by 3GPP. LTE-A will meet or exceed the requirements of the International Telecommunication Union (ITU) for the fourth generation (4G) radio communication standard known as IMT-Advanced. This series of articles traces the evolution of 4G and LTE-Advanced, explaining the architectures and their implications for both carriers and consumers.More...
There’s hardly a cell phone on the planet that doesn’t have a Bluetooth transceiver for connecting to a wireless headset. Most new PCs now incorporate Bluetooth chips for the same purpose, letting you type while you talk or listen. Many, if not most new cars, have Bluetooth to let you talk hands free while driving. However, while that’s all well and good, there is a wide range of applications for which Bluetooth isn’t appropriate – or at least it wasn’t until now. Bluetooth Low Energy was designed from the beginning to be an ultra-low-power (ULP) protocol to service short range wireless devices that may need to run for months or even years on a single coin cell battery. More...
Many appliances found in homes rely on low or fractional horsepower three-phase motors. These end applications frequently require galvanic isolation for safety, ground noise mitigation and/or voltage level shifting. CMOS-based isolation technology has given rise to isolated gate drivers, multi-channel digital isolators and AC current sensors that offer significant gains in performance and reliability compared to legacy galvanic isolation techniques. More...
Active or dynamic power is largely the power required to switch logic gates. As processors have become more complex, moving to smaller process geometries has continually reduced core voltages, with the resulting power savings far outweighing the added current load of the extra transistors. Thanks to Ohm's Law, core voltage (VDDCORE) has a dramatic impact on both active and static power. Still, with Moore's Law now running headlong into some laws of physics, that free ride is coming to an end. More...
The most common types of RF front-ends for software radios are dual conversion, single conversion, and tuned radio frequency receivers. The designer needs to weigh the multitude of combinations before arriving at the optimal design and, generally, a trade-off occurs between sensitivity and selectivity. Higher-order conversion receivers (with multiple downconversion stages) may be the best solution in some situations, but more mixers may mean more spurious signals, particularly when high-power signals are present. More...
Electric vehicles (EVs) are growing in popularity, but "range anxiety" isn't going away. Unfortunately when you're on the road, electrons are a lot harder to come by than gasoline, due to the lack of EV charging stations. Fortunately, a number of companies are rushing to fill the void, and a number of cities and states, and even the federal government are providing incentives to install them. More...
In historical terms, the death of the flint tool, cooking by dung and other bygone technologies occurred very rapidly. This was because several factors conspired to bring in the better alternative and this created a multiplier effect. So it is with lead acid batteries. Every month another threat appears that seems modest but, on closer examination, constitutes a serious nail in the coffin for an industry that has served the world well for over one hundred years.More...
Wireless power systems are emerging as a practical option for conveniently recharging mobile phones and other handheld devices. Implementing an industry standard interface allows a common charging pad (TX) to recharge multiple types of battery-operated devices (RX). The WPC developed the Qi standard for wireless power systems with up to 5W of output power. This allows complete interoperability between transmitters and receivers independent of device manufacturer. More...
The motivation for the article is to present methods of enhancing a wireless link in a typical environment of simple low-power wireless transceivers. This article focuses on maximizing the reliability of a wireless link, while keeping the overall hardware costs down. For many simple transceivers the added overhead of using frequency-hopping diversity hardly seems worth while, however, this article presents strong technical reasons why this should be considered even for simple applications. More...
So how much energy does regenerative braking put back into the system when you’re driving downhill with your foot off the accelerator? It depends on the kinetic energy of the car, plus the speed/wind drag, road grade, deceleration, and system controller’s algorithm. The basic answer is, “Not a lot—but it helps.” Still, the fact that you can recoup some of the energy that it took to get up to speed or up the mountain is one of those nice benefits that come with an electric vehicle. More...
Normally you order an evaluation kit to check out whether a particular microcontroller seems appropriate for a design you have in mind; if everything seems OK, you then order a more costly development kit to prototype your design. Cypress’ CY3267 PowerPSoC Lighting Evaluation Kit manages to cross that line, enabling a quick out-of-the-box evaluation within a few minutes but including a full suite of tools, circuits, and programmable components to enable developing some sophisticated lighting control systems. More...
Unfortunately, traditional test instruments are not well suited for measuring dynamic power in battery-powered devices. Digital multimeters (DMMs) can accurately measure over the dynamic range, for example, but they cannot measure rapid changes over time. Oscilloscopes can measure rapid changes over time, but due to the need for a current probe or shunt they lack accuracy (not enough vertical resolution) and dynamic range. Are SMUs a solution? It depends. More...
While most power supplies used to power the DUT have built-in current measurements that can measure ampere and milliampere level current quite accurately, they may not be able make the microampere current measurements needed to measure sleep mode or leakage. In this article, we will cover methods used to measure current flowing from the battery into the electronic device (or within sub-circuits of the device) and how modern power management schemes create challenges for measuring these currents. More...
Computers, electronic devices and machines all talk to each other exchanging volumes of information in a variety of scenarios. More than just communicate with each other, these devices form a vast, IP-based network – ‘the Internet of Things.’ In this article, we look at how these low power battery operated devices can benefit from 11n and why new designs will use 11n rather than 11g. More...
When you run low on gas you look for a handy gas station. What happens when you’re driving an electric vehicle (EV) and you run short of electrons? Unless you’re doing an out-and-back run from your home charging station, you could have a problem. Right now the market for EVs is primarily early adopters, such as engineers who love the cool technology and who, coincidentally, may also want to save some money—having first parted with a goodly chunk of it—along with the environment. EVs will have to go mass market in a big way before the recharging infrastructure begins to rival that for internal combustion engines. It’s Catch-22: lack of infrastructure slows adoption of a technology, which in turn needs the infrastructure to really take off. The solutions lie at both the personal and system level. More...
As enterprise data centers expand to support cloud-based services, network managers are faced with an uncomfortable paradox: Exponential growth of users demanding high-bandwidth service is driving architectures that offer unprecedented density of 100-Mbit and 1-Gbit ports in a single line card, even as power costs and green initiatives place new demands for energy efficiency in the data center. While some power-saving improvements can be implemented at the level of the enterprise LAN, the biggest opportunity for cutting overall power dissipation in the data center resides in the semiconductors comprising the Ethernet interface.More...
The ITU reckons that about 10% of total emissions attributable to information and communications technology (ICT) are attributable to mobile phone networks, with between 55% and 60% of the energy consumed being used in the radio access network. With macrocell base-stations consuming anything from 2.5kW to 4kW each, and national networks using tens of thousands of them, that’s a lot of energy, and a lot of emissions, being used to connect mobile devices. More...
When you step on the gas in an ordinary car, most of us have a pretty good idea what happens, having driven them since we were teenagers. But what happens when you depress the accelerator in a Volt? A lot more than you might expect. The Volt has three power sources: a 111 kW electric motor, a 55 kW motor/generator, and a 62 kW gas engine. Driving conditions dictate when they work together; and the Volt’s unique electric drive system dictates how they work together. More...
We're delighted to welcome tireless wireless analyst Will Strauss to the Low-Power Design family. Will is President and Principal Analyst at Phoenix-based Forward Concepts, where he's been covering the semiconductor and wireless industries since 1984. Previously Will was Executive VP at In-Stat Incorporated, and earlier was VP of Market Research at Integrated Circuit Engineering Corporation. Please welcome Will to Low-Power Design and keep up to date on the latest wireless industry developments by following his blog. More...
Fossil-fueled electric power facilities have proven to be robust and reliable sources of energy for more than a century, but these tried-and-true facilities are large, complex and increasingly expensive to build. It is also challenging and costly to operate them cleanly with minimal carbon footprint and environmental impact. In contrast, modern photovoltaic (PV) power systems offer a sustainable alternative to fossil-fueled power plants, providing lower long-term operating costs, modular scalability, higher efficiency and a significantly lower carbon footprint compared to centralized power generating facilities. More...
Photovoltaic (PV) solar technology is at the heart of the multi-billion dollar clean/green/renewable energy industry, powering everything from road signs to entire cities. While solar cells themselves are essentially just big PN-junction semiconductors, there’s a lot of advanced and rapidly evolving electronic engineering required to optimize the energy transfer from the rooftop to the grid. This course covers the fundamentals of grid-connected PV systems, with the aim of providing engineers with a good overview of the technologies, topologies and electronics that make up such systems. More...
This course covers the fundamentals of off-grid, stand-alone photovoltaic (PV) systems, with the aim of providing engineers with a good overview of the technologies, topologies and electronics that make up such systems. The course content includes:
• Introduction to Photovoltaic Systems
• Grid-Connected vs. Off-Grid Solar Systems
• Solar Energy Storage
• Charge Controllers
• Power Conditioning
• Energy Harvesting
• Integration Issues More...
