Wednesday, March 25, 2020

Modeling and Practical Design Dual-Mode Sinewave and Common Mode Filter for PWM Motor Drives System Using Tricore Laminations

Tin Luu, MTE, March 25, 2020

A dual-mode sinewave output filter that eliminates motor problems due to the PWM waveforms in both common mode and differential mode operation is proposed. A three-phase inductor constructed with tricore laminations. The windings possess differential mode inductance and proportionally every large common mode inductance characteristic. In voltage source converters, the common mode voltage is mainly distributed in the switching frequency range, therefore the common mode voltage in this filter design is in the medium frequency range referring to the switching frequency and sidebands of its integral multiples. The single integrated inductor with the capacitors creates a LC lowpass filter in both common mode and differential mode operation. This proposed filter offers a complete solution with reliable, practical and cost-effective to the issues caused by common mode voltage in power converter systems. Three different rating of 5A, 45A and 160A prototypes were built, and test results presented.

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Monday, March 23, 2020

Getting the Voids Out

MACOM, March 23, 2020

Reducing solder voids is a pervasive challenge affecting the electronics industry.  With higher thermal dissipation requirements placed upon the attachment of a device to a circuit board the number of voids within the solder joint becomes critical.  There are various considerations that need to be taken into account, including 1) the design of the substrate 2) the surface condition of the part being attached 3) the type of solder selected 4) the reflow profile 5) pattern and volume of paste deposition, among others.  Let’s dive further into some of these considerations:

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Thursday, February 20, 2020

(Semi)Conducting a way through the AIoT

XMOS, February 20, 2020

The IoT describes connected “things” – a diverse range of “things” that have an internet connection and can be controlled and/or interrogated from anywhere on the web. They can be anything from toys to industrial robots, from cars to rice cookers. Going forward, the application of machine learning to the data inputs from connected devices takes us into the Artificial Intelligence of Things: where data is given context and the end user experience is elevated into a natural, seamless interaction with technology. Catering for such a wide range of product requirements is a growing challenge for the semiconductor industry.

Historically the semiconductor business has been defined and driven by a series of dominant sectors – from defence applications in the 70s, to enterprise applications in the 80s and early 90s. By the millennium, the consumer device sector had exploded into life. Even then, the feature-sets and roadmaps for each sector were relatively predictable, enabling vendors to build a series of highly optimised solutions.  

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Monday, February 17, 2020

Internet From The Stars: 21st Century Space Race

Jaime Jones, NuWaves Engineering, February 17, 2020

Two weeks ago, SpaceX launched it’s third successful mission placing 60 more Starlink satellites into low earth orbit, bringing the total number of global internet powering satellites to 180. That is far from the planned system completion threshold of 12,000, but it does establish that SpaceX has the formula down and isn’t going to stop any time soon. While 12,000 may be a few years away, Elon Musk, founder and CEO of SpaceX, has stated that 400 satellites would provide “minor” internet coverage and 800 satellites would achieve “moderate” or significant operational” coverage. Each subsequent launch of 60 satellites would deliver 1 terabit of bandwidth, potentially supporting 40,000 users streaming ultra-high-definition content at once. It’s safe to say with numbers like those, internet from space is going to be a house hold topic for years to come.

Musk has stated that one of the primary reasons for creating the Starlink system was to bring low cost internet to all areas of the globe and to give traditional telecommunication companies more realistic competition. Everyone is familiar with how current telecom companies have monopolized local areas, establishing themselves as the only viable internet options in the process. But how will competition work with space internet? There aren’t any wires in run in space, so can there be infinite companies providing service through satellites?

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Thursday, January 23, 2020

Energy consumption is a hot topic in the world of voice-enabled AIoT devices. With good reason.

Mark Lippett, XMOS, January 23, 2020

Voice shows the fastest adoption of any consumer technology ever. At the current rate of growth, there’ll be a further 1.5 billion new voice-enabled devices in our homes in 2025, with an estimated 5 billion units in use worldwide.

Imagine all these devices powered up and hanging on to our every keyword. At a very rough estimate, those devices will consume 65 TeraWatt hours of electricity a year, simply by being always on, listening for a keyword. That’s almost the equivalent (90%) of the annual output of the world’s largest nuclear power plant. It’s not sustainable. Intelligent IoT systems should enable us to consume less, not more. 

As voice becomes a mainstream requirement and the focus moves inexorably forward to contextual, conversational interfaces, so we’re also seeing a shift in the semiconductor industry, with increasing innovation (and demand) around energy efficient solutions.

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Tuesday, January 7, 2020

Non-Linear Transmission Line Comb Generators Part-1: The Phase Noise Problem and Comb Generation

MACOM, January 07, 2020

In this two-part series from MACOM, we will delve into Non-Linear Transmission Line (NLTL) Comb Generators, first understanding the phase noise problem, and understanding a potential solution to the problem. In the second part of the blog series, we will explore NLTL comb generation, compare it to its predecessor comb generation using Step Recovery Diodes and see how the NLTL comb generation approach can enable improved sensitivity and lower bit error rates in communication systems.


Figure 1: Typical Superheterodyne Receiver
The Phase Noise Problem

Let’s start with the problem with circuits requiring low noise performance. Below we see a block diagram of the RF and IF portions of a typical superheterodyne receiver.  A weak signal is received at the antenna – 1) optionally amplified by a low noise amplifier, 2) filtered to reduce the effects of broadband noise and interferer signals whose frequencies may be close to that of the desired signal and then 3) downconverted to a lower, intermediate frequency for further processing. 

In the ideal case, the downconverter mixer mixes the received signal with a single-frequency local oscillator signal.  In the real case though, the local oscillator signal never comprises a single frequency, but is always accompanied by close-in noise sidebands which are generated in the local oscillator signal chain.  Also, the received signal may be accompanied by close-in interfering signals which cannot be completely removed by the band pass filter.

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