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NS Nanotech Inc of Ann Arbor, MI, USA — a University of Michigan Electrical and Computer Engineering (ECE) spin-off co-founded by professor Zetian Mi in 2017 that develops gallium nitride nanowire LEDs for visible displays and UVC disinfection applications — has appointed John Bayne to its board of directors...

Cree LED Inc of Durham, NC, USA (a Penguin Solutions brand) has launched its new CV28D LEDs with FusionBeam Technology, providing an advance for the LED signage market. The CV28D LED combines the latest through-hole and surface-mount (SMD) RGB LED technology, delivering what is claimed to be superior directionality, image quality and resolution in a durable, easy-to-assemble package...

I got so fed up with the stupid interface on the front of my automatic cat feeders that I decided to make a web interface and use the ESP8266 to control them. They are very simple devices. Across two different brands of feeders I have they use the same internal mechanism, so this should work pretty universally across all generic-looking cat feeders... I was going to design a custom PCB but the circuit is so simple it was pointless and would've taken weeks to arrive. I cut the original wiring harness and crimped on JST-XH connectors to make it look somewhat professional. cat feeder from brand #1 wired to my board cat feeder from brand #2 wired to my board The prefboard I made (I made 3x of them) You can check out the code and some more images of the feeders and board (front/back/etc) here: https://github.com/captmicr0/EspCatFeeder submitted by /u/rhyno95_ [link] [comments]

On 14 November, Tokyo-based Mitsubishi Electric Corp is commencing shipment of samples of a silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) bare die for use in drive-motor inverters of electric vehicles (EVs), plug-in hybrid vehicles (PHEVs) and other electric vehicles (xEVs)...

Often, one needs a simple low voltage sinusoidal oscillator with good amplitude and frequency stability and low harmonic distortion; here, the Peltz oscillator becomes a viable candidate. Please see the Peltz oscillator Analog Devices Wiki page here and a discussion on my Peltz oscillator here.

Wow the engineering world with your unique design: Design Ideas Submission Guide

Shown in Figure 1, the Peltz oscillator requires only two transistors, one capacitor, one inductor and one resistor. In this configuration, the output voltage is a ground referenced, direct coupled, low distortion sinewave, swinging above and below ground at ~1 Vbe, while operating from a low negative supply voltage (AAA battery).

Figure 1 Basic configuration of a Peltz oscillator with a low component count yielding a low distortion sinewave output.

The oscillating frequency is shown:

A simplified analysis shows the minimum negative supply voltage (Vee) is:

Where Vt is the Thermal Voltage (kT/q), Z is the total impedance “seen” at the parallel resonant LC network, Vbe is the base emitter voltage of Q1 [Vt*ln(Ic/Is)], and Is is the transistor saturation current.

Here’s an example with a pair of 2N3904s, a 470 µH inductor, 0.22 µF capacitor, and a 510 Ω bias resistor, powered from a single AAA cell (the oscillator actually works at ~0.7 VDC), producing a stable, low noise ~16 kHz sinewave as shown in Figure 2, Figure 3, and Figure 4.

Figure 2 Peltz oscillator output with a clean 16 kHz sinewave.

Figure 3 Spectral view of sinewave showing fundamental as well as 2nd and 3rd harmonics.

Figure 4 Zoomed in view of ~16 kHz sinewave.

Note the output frequency, peak to peak amplitude and overall waveform quality is not bad for a 5-element oscillator!

Michael A Wyatt is a life member with IEEE and has continued to enjoy electronics ever since his childhood. Mike has a long career spanning Honeywell, Northrop Grumman, Insyte/ITT/Ex-elis/Harris, ViaSat and retiring (semi) with Wyatt Labs. During his career he accumulated 32 US Patents and in the past published a few EDN Articles including Best Idea of the Year in 1989.

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The post Simple 5-component oscillator works below 0.8V appeared first on EDN.

ROHM Semiconductor has launched surface-mount SiC Schottky barrier diodes (SBDs) that improve insulation resistance by increasing the creepage distance between terminals. The initial lineup includes eight models (SCS2xxxNHR) for automotive applications such as on-board chargers (OBCs) and DC-DC converters (available now), with plans to deploy eight additional models (SCS2xxxN) for industrial equipment such as factory automation (FA) devices (e.g. AC servo motors for industrial robots) and photovoltaic (PV) inverters, power conditioners, uninterruptible power supplies (UPS) etc (scheduled to be available) in December...

submitted by /u/gb_14 [link] [comments]

submitted by /u/_justforamin_ [link] [comments]

Hey everyone! I’m excited to share my latest project: a tiny, open-source RP2040-based board with an integrated addressable LED matrix. It’s built on a 4-layer PCB, and the LEDs are ultra-small (just 1mm x 1mm each), using WS2812 for full addressability. https://preview.redd.it/5whyzmxtta0e1.jpg?width=1800&format=pjpg&auto=webp&s=f3c11d04357dbf23259972b1255bea51caf96379 https://preview.redd.it/4hhhaijuta0e1.jpg?width=1800&format=pjpg&auto=webp&s=dd44466247e926234ba572ed3b7222cdddf1bdc9 submitted by /u/TheBusDriver69 [link] [comments]

Silicon carbide wafer manufacturing technology firm TekSiC AB of Linköping, Sweden has appointed Joachim Tollstoy as chief executive officer, effective 7 October. With over 15 years of leadership experience, Tollstoy has an understanding of market dynamics that TekSiC reckons will be essential as it navigates the evolving landscape of silicon carbide manufacturing...

I mentioned recently that for the third time in roughly a decade, a subset of the electronics suite in my residence had gotten zapped by a close-proximity lightning storm. Although this follow-up writeup, one of a planned series, was already proposed to (and approved by) Aalyia at the time, subsequent earlier-post comments exchanges with a couple of readers were equal parts informative and validating on this one’s topical relevance.

First off, here’s what reader Thinking_J had to say:

Only 3 times in a 10-year span, in the area SW of Colorado Springs?

Brian, you appear to be lucky.

https://www.cbsnews.com/colorado/news/lightning-dangers-traditional-beliefs-researchers-colorado-update-ideas-storms-denver/

My response:

Southwest of Golden (and Denver, for that matter), not Colorado Springs, but yes, the broader area is active each year’s “monsoon season”:

https://climate.colostate.edu/co_nam.html

The “monsoon season” I was referencing historically runs from mid-June through the end of September. Storms normally fire up beginning mid-afternoon and can continue overnight and into the next morning. As an example of what they look like, I grabbed a precipitation-plot screenshot during a subsequent storm this year; I live in Genesee, explicitly noted on the map:

Wild, huh?

Then there were the in-depth thoughts of reader “bdcst”, in a posting only the first half of which I’ve republished here for brevity (that said, I encourage you to read the post in its entirety at the original-published location):

Hi Brian,

Several things come to mind. First is, if you think it was EMP, then how will moving your copper indoors make a difference unless you live in a Faraday cage shielded home? The best way to prevent lightning induced surges from entering your equipment via your network connection, is to go to a fiber drop from your ISP, cable or telecom carrier. You could also change over to shielded CAT-6 Ethernet cable.

 At my broadcast tower sites, it’s the incoming copper, from the tower, or telephone system or from the power line itself that brings lighting induced current indoors. Even with decent suppressors on all incoming copper, the only way to dissipate most of the differential voltage from the large current spikes is with near zero ohms bonding between every piece of equipment and to a single very low impedance earth ground point. All metal surfaces in my buildings are grounded by large diameter flexible copper wire, even the metal entrance door is bonded to it bypassing the resistance of its hinges.

 When I built my home at the end of a long rural power line, I experienced odd failures during electrical storms. I built my own power line suppressor with the largest GE MOV’s I could find. That eliminated my lightning issues. Of course, surge suppressors must have very low resistance path to ground to be effective. If you can’t get a fiber drop for your data, then do install several layers of Ethernet suppressors between the incoming line and your home. And do install at least a small AC line suppressor in place of a two-pole circuit breaker in your main panel, preferably at the top of the panel where the main circuit breaker resides.

My response, several aspects of which I’ll elaborate on in this writeup:

Thanks everso for your detailed comments and suggestions. Unfortunately, fiber broadband isn’t an option here; I actually feel fortunate (given its rural status) to have Gbit coax courtesy of Comcast:

 https://www.edn.com/a-quest-for-faster-upstream-bandwidth/

 Regarding internal-vs-external wired Ethernet spans, I don’t know why, but the only times I’ve had Ethernet-connected devices fry (excluding coax and HDMI, which also have been problematic in the past) are related to those (multi-port switches, to be precise) on one or both ends of an external-traversed Ethernet span. Fully internal Ethernet connections appear to be immune. The home has cedar siding and of course there’s also insulation in the walls and ceiling, so perhaps that (along with incremental air gaps) in sum provides sufficient protection?

 Your question regarding Ethernet suppressors ties nicely into one of the themes of an upcoming planned blog post. I’ve done only rudimentary research so far, but from what I’ve uncovered to date, they tend to be either:

1. Inexpensive but basically ineffective or
2. Incredibly expensive, but then again, replacement plasma TVs and such are pricey too (http://www.edn.com/electronics-blogs/brians-brain/4435969/lightning-strike-becomes-emp-weapon-)

Plus, I’m always concerned about bandwidth degradation that may result from the added intermediary circuitry (same goes for coax). Any specific suggestions you have would be greatly appreciated.

 Thanks again for writing!

Before continuing, an overview of my home network will be first-time informative for some and act as a memory-refresher to long-time readers for whom I’ve already touched on various aspects. Mine’s a two-story home, with the furnace room, roughly in the middle of the lower level, acting as the networking nexus. Comcast-served coax enters there from the outside and, after routing through my cable modem and router, feeds into an eight-port GbE switch. From there, I’ve been predominantly leveraging Ethernet runs originally laid by the prior owner.

In one direction, Cat 5 (I’m assuming, given its age, versus a newer generation) first routes through the interstitial space between the two levels of the house to the far wall of the family room next to the furnace room, connecting to another 8-port GbE switch. At that point, another Ethernet span exits the house, is tacked to the cedar wood exterior and runs to the upper-level living room at one end of the house, where it re-enters and connects to another 8-port GbE switch. In the opposite direction, another Cat 5 span exits the house at the furnace room and routes outside to the upper-level master bedroom at the other end of the house, where it re-enters and connects to a five-port GbE switch. Although the internal-only Ethernet is seemingly comprised of conventional unshielded cable, judging from its flexibility, I was reminded via examination in prep for tackling this writeup that the external wiring is definitely shielded, not that this did me any protective good (unsurprisingly, sadly, given that externally-routed shielded coax cable spans from room to room have similarly still proven vulnerable in the past).

Normally, there are four Wi-Fi nodes in operation, in a mesh configuration comprised of Google Nest Wifi routers:

1. The router, in the furnace room downstairs
2. A mesh point in the master bedroom upstairs at one end of the house
3. Another in the living room upstairs at the other end of the house
4. And one more downstairs, in an office directly below the living room

Why routers in the latter three cases, versus less expensive access points? In the Google Nest Wifi generation, versus with the Google OnHub and Google Wifi precursors (as well as the Google Nest Wifi Pro successor, ironically), access points are only wirelessly accessible; they don’t offer Ethernet connectivity as an option for among other things creating a wired “mesh” backbone (you’ll soon see why such a backbone is desirable). Plus, Google Nest Wifi Routers’ Wi-Fi subsystems are more robust; AC2200 MU-MIMO with 4×4 on 5 GHz and 2×2 on 2.4GHz, versus only AC1200 MU-MIMO Wi-Fi 2×2 on both 2.4 GHz and 5 GHz for the Google Nest Wifi Point. And the Point’s inclusion of a speaker is a don’t-care (more accurate: a detriment) to me.

I’ve augmented the already-existing Ethernet wiring when we bought the house with two other notable additional spans, both internal-only. One runs from the furnace room to my office directly above it (I did end up replacing the original incomplete-cable addition with a fully GbE-complaint successor). The other goes through the wall between the family room and the earlier-mentioned office beyond it (and below the living room), providing it with robust Wi-Fi coverage. As you’ll soon see, this particular AP ended up being a key (albeit imperfect) player in my current monsoon-season workaround.

Speaking of workarounds, what are my solution options, given that the outdoor-routed Ethernet cable is already shielded? Perhaps the easiest option would be to try installing Ethernet surge protectors at each end of the two outdoors-dominant spans. Here, for example are some that sell for $9.99 a pair at Amazon (and were discounted to $7.99 a pair during the recent Prime Fall Days promotion; I actually placed an order but then canceled it after I read the fine print):

As the inset image shows and the following teardown image (conveniently supplied by the manufacturer) further details, they basically just consist of a bunch of diodes:

This one’s twice as expensive, albeit still quite inexpensive, and adds an earth ground strap:

Again, nothing but diodes (the cluster of four on each end are M7s; I can’t read the markings on the middle two), though:

Problem #1: diving into the fine print (therefore my earlier mentioned order cancellation), you’ll find that they only support passing 100 Mbit Ethernet through, not GbE. And problem #2; judging from the user comments published on both products, they don’t seem to work, at least at the atmospheric-electricity intensities my residence sees.

Ok, then, if my observation passes muster that internal-only Ethernet spans, even unshielded ones, are seemingly EMI-immune, why not run replacement cabling from the furnace room to both upper-level ends of the house through the interstitial space between the levels, as well as between the inner and outer walls? That may indeed be what I end up biting the bullet and doing, but the necessary navigation around (and/or through) enroute joists, ductwork and other obstacles is not something that I’m relishing, fiscally or otherwise. In-advance is always preferable to after-the-fact when it comes to such things, after all! Ironically, right before sitting down to start writing this post, I skimmed through the final print edition of Sound & Vision magazine, which included a great writeup by home installer (and long-time column contributor) John Sciacca. There’s a fundamentally solid reason why he wrote the following wise words!

A few of my biggest tips: Prewire for everything (a wire you aren’t using today might be a lifesaver tomorrow!), leave a conduit if possible…

What about MoCA (coax-based networking) or powerline networking? No thanks. As I’ve already mentioned, the existing external-routed coax wiring has proven vulnerable to close-proximity lightning, too. If I’m going to run internally routed cable instead, I’ll just do Ethernet. And after several decades’ worth of dealing with powerline’s unfulfilled promise due to its struggles to traverse multiple circuit breakers and phases, including at this house (which has two breaker boxes, believe it or not, the original one in the garage and a newer supplement in the furnace room), along with injected noise from furnaces, air conditioning units, hair dryers, innumerable wall warts and the like, I’ve frankly collected more than enough scars already. But speaking of breaker boxes, by the way, I’ve already implemented one of the earlier documented suggestions from reader “bdcst”, courtesy of an electrician visit a few years back:

The final option, which I did try (with interesting results), involved disconnecting both ends of the exterior-routed Cat 5 spans and instead relying solely on wireless backbones for the mesh access points upstairs at both ends of the house. As setup for the results to come, I’ll first share what the wired-only connectivity looks like between the furnace room and my office directly above it. I’m still relying predominantly on my legacy, now-obsolete (per Windows 8’s demise) Windows Media Center-based cable TV-distribution scheme, which has a convenient built-in Network Tuner facility accessible via any of the Xbox 360s acting as Windows Media Extenders:

In preparation for my external-Ethernet severing experiment, to maximize the robustness of the resultant wireless backbone connectivity to both ends of the house, I installed a fifth Google Nest Wifi router-as-access point in the office. It indeed resulted in reasonably robust, albeit more erratic, bandwidth between the router and the access point in the living room, first as reported in the Google Home app:

and then by Windows Media Center’s Network Tuner:

I occasionally experienced brief A/V dropouts and freezes with this specific configuration. More notably, the Windows Media Center UI was more sluggish than before, especially in its response to remote control button presses (fast-forward and -rewind attempts were particularly maddening). Most disconcerting, however, was the fact that my wife’s iPhone now frequently lost network connectivity after she traversed from one level of the house to the other, until she toggled it into and then back out of Airplane Mode.

One of the downsides of mesh networks is that, because all nodes broadcast the exact same SSID (in various Google Wifi product families’ case), or the same multi-SSID suite for other mesh setups that use different names for the 2.4 GHz, 5 GHz, and 6 GHz beacons, it’s difficult (especially with Google’s elementary Home utility) to figure out exactly what node you’re connected to at any point in time. I hypothesized that her iPhone was stubbornly clinging to the now-unusable Wi-Fi node she was using before versus switching to the now-stronger signal of a different node in her destination location. Regardless, once I re-disconnected the additional access point in my office, her phone’s robust roaming behavior returned:

But as the above screenshot alludes to, I ended up with other problems in exchange. Note, specifically, the now-weak backbone connectivity reported by the living room node (although, curiously, connectivity between the master bedroom and furnace room remained solid even now over Wi-Fi). The mesh access point in the living room was, I suspect, now wirelessly connected to the one in the office below it, ironically a shorter node-to-node distance than before, but passing through the interstitial space between the levels. And directly between the two nodes in that interstitial space is a big hunk of metal ductwork. Note, too, that the Google Nest Wifi system is based on Wi-Fi 5 (802.11ac) technology, and that the wireless backbone is specifically implemented using the 5 GHz band, which is higher-bandwidth than its 2.4 GHz counterpart but also inherently shorter-range. The result was predictable:

The experiment wasn’t a total waste, though. On a hunch, I tried using the Xfinity Stream app on my Roku to view Comcast-sourced content instead. The delivery mechanism here is completely different: streamed over the Internet and originating from Comcast’s server, versus solely over my LAN from the mini PC source (in all cases, whether live, time-shifted or fully pre-recorded, originating at my Comcast coax TV feed via a SiliconDust HDHomeRun Prime CableCARD intermediary). I wasn’t direct-connecting to premises Wi-Fi from the Roku; instead, I kept it wired Ethernet-connected to the multi-port switch as before, leveraging the now-wireless-backbone-connected access point also connected to the switch there instead. And, as a pleasant surprise to me, I consistently received solid streaming delivery.

What’s changed? Let’s look first at the video codec leveraged. The WTV “wrapper” (container) format now in use by Windows Media Center supersedes the DVR-MS precursor with expanded support for both legacy MPEG-2 and newer MPEG-4 video. And indeed, although a perusal of a recent recorded-show file in Window Explorer’s File Properties option was fruitless (the audio and video codec sections were blank), pulling the file into VLC Media Player and examining it there proved more enlightening. There were two embedded audio tracks, one English and the other Spanish, both Dolby AC3-encoded. And the video was encoded using H.264, i.e., MPEG-4 AVC (Part 10). Interestingly, again according to VLC, it was formatted at 1280×720 pixel resolution and a 59.940060 fps frame rate. And the bitrate varied over time, confirmative of VBR encoding, with input and demuxed stream bitrates both spiking to >8,000 kb/sec peaks.

The good news here, from a Windows Media Center standpoint, is two-fold: it’s not still using archaic MPEG-2 as I’d feared beforehand might have been the case, and the MPEG-4 profile in use is reasonably advanced. The bad news, however, is that it’s only using AVC, and at a high frame rate (therefore bitrate) to boot. Conversely, Roku players also support the more advanced HEVC and VP9 video codec formats (alas, I have no idea what’s being used in this case). And, because the content is streamed directly from Comcast’s server, the Roku and server can communicate to adaptively adjust resolution, frame rate, compression level and other bitrate-related variables, maximizing playback quality as WAN and LAN bandwidth dynamically vary.

For now, given that monsoon season is (supposedly, at least) over until next summer, I’ve reconnected the external Cat 5 spans. And it’s nice to know that when the “thunderbolt and lightning, very, very frightening” return, I can always temporarily sever the external Ethernet again, relying on my Rokus’ Xfinity Stream apps instead. That said, I also plan to eventually try out newer Wi-Fi technology, to further test the hypothesis that “wires beat wireless every time”. Nearing 3,000 words, I’ll save more details on that for another post to come. And until then, I as-always welcome your thoughts in the comments!

—Brian Dipert is the Editor-in-Chief of the Edge AI and Vision Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the company’s online newsletter.

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• Teardown: Ethernet and EMP take out TV tuner

The post The whole-house LAN: Achilles-heel alternatives, tradeoffs, and plans appeared first on EDN.

Fabless firm Cambridge GaN Devices Ltd (CGD) — which was spun out of the University of Cambridge in 2016 to design, develop and commercialize power transistors and ICs that use GaN-on-silicon substrates — and Qorvo Inc of Greensboro, NC, USA (which provides core technologies and RF solutions for mobile, infrastructure and defense applications) have partnered to bring together motor control and power efficiency technologies in the PAC5556A + ICeGaN evaluation kit (EVK). The collaboration combines Qorvo’s BLDC/PMSM motor controller/driver and CGD’s ICeGaN ICs in a board that is said to significantly improve motor control applications...

For its fiscal second-quarter 2025 (ended 28 September 2024), Qorvo Inc of Greensboro, NC, USA (which provides core technologies and RF solutions for mobile, infrastructure and defense applications) has reported revenue of $1046.5m. This is down 5.2% on $1103.5m a year ago due mainly to a hiatus in Android smartphone revenues, following ramps in first-half calendar 2024 for key models including both Samsung’s S24 (involving over $5 of content) and Google’s Pixel ($15 of content). However, revenue has rebounded by 18% from $886.7m last quarter. It also exceeds the $1025m guidance, driven by double-digit sequential growth in all three operating segments...

Efficient Power Conversion Corp (EPC) of El Segundo, CA, USA — which makes enhancement-mode gallium nitride on silicon (eGaN) power field-effect transistors (FETs) and integrated circuits for power management applications — says that the US International Trade Commission (ITC) has affirmed its initial determination that gallium nitride-on-silicon (GaN-on-Si) power solutions firm Innoscience of Suzhou, China infringed EPC’s foundational patent for GaN technology, which is core to applications involving artificial intelligence, satellites, rapid chargers, humanoid robots and autonomous driving, among others...

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Smart home devices are becoming increasingly popular with many households adopting smart thermostats, lighting systems, security systems, and home entertainment systems. These devices provide automation and wireless control of household functions, allowing users to monitor and control their homes from a mobile app or digital interface.

But despite the advantages of smart home devices, users also face an increased risk of electrical malfunctions that may result in electric shock, fire, or direct damage to the device. This article discusses the importance of integrating digital isolators in smart home devices to ensure safety and reliability.

Definition of a digital isolator

A digital isolator is an electronic device that provides electrical isolation between two circuits while allowing digital signals to pass between the circuits. By using electromagnetic or capacitive coupling, the digital isolator transmits data across the isolation barrier without requiring a direct electrical connection.

Digital isolators are often used in applications where electrical isolation is necessary to protect sensitive circuitry from high voltages, noise, or other hazards. They can be used in power supplies, motor control, medical devices, industrial automation, and other applications where safety and reliability are critical. Figure 1 shows a capacitive isolation diagram.

Figure 1 The capacitive isolation diagram includes the top electrode, bottom electrode, and wire bonds. Source: Monolithic Power Systems

Understanding isolation rating

The required isolation voltage is an important consideration when choosing a digital isolator, since it impacts the total solution cost. Isolators generally have one of two isolation classifications: basic isolation or reinforced isolation.

• Basic isolation: This provides sufficient insulation material to protect a person or device from electrical harm; however, the risk of electrical malfunctions is still present if the isolation barrier is broken. Some devices use two layers of basic isolation as a protective measure in the case of the first layer breaking; this is called double isolation.
• Reinforced isolation: This is equivalent to dual basic isolation and is implemented by strengthening the isolation barrier to decrease the chances of the barrier breaking compared to basic isolation.

Figure 2 shows the three types of isolation: basic isolation, double isolation, and reinforced isolation.

Figure 2 The three types of isolation are basic isolation, double isolation, and reinforced isolation. Source: Monolithic Power Systems

Here, creepage distance is the shortest distance between two conductive elements on opposite sides of the isolation barrier and is measured along the isolation surface. Clearance distance is a common parameter that is similar to creepage distance but is measured along a direct path through the air.

As a result, creepage distance is always equal to or greater than the clearance distance, but both are heavily dependent on the IC’s package structure. Parameters such as pin-to-pin distance and body width have a strong correlation with the isolation voltage for isolated components. Wider pin-to-pin spacing and packages have larger isolation voltages, but they also take up more board space and increase the overall system cost.

Depending on the system design and isolation voltage requirements, different isolation ratings are available, typically corresponding to the package type. Small outline integrated circuit (SOIC) packages often have 1.27-mm pin-to-pin spacing and are available in narrow body (3.9-mm package width) or wide body (7.5-mm package width) formats.

The wide-body package is commonly used for meeting reinforced 5-kVRMS requirements, while the narrow-body package is used in applications where the maximum withstand isolation voltage is 3k VRMS. In some cases, extra wide-body packages are used with >14.5-mm creepage for certain 800-V+ systems to meet the creepage and clearance requirements.

Figure 3 shows the clearance and creepage distances in an SOIC package.

Figure 3 Varying clearance and creepage distances are used in SOIC packages to meet design requirements. Source: Monolithic Power Systems

Safety regulations for digital isolators

Safety certifications such as UL 1577, VDE, CSA, and CQC play a pivotal role in ensuring the reliability and safety of digital isolators within various electronic systems. These certifications are described below:

• UL 1577: This certification, established by Underwriters Laboratories, sets stringent standards to evaluate the insulation and isolation performance of digital isolators. Factors including voltage isolation, leakage current, and insulation resistance are examined to ensure compliance with safety requirements.
• VDE: This certification is predominantly recognized in Europe and verifies the quality and safety of electrical products, including digital isolators, through rigorous testing methodologies. VDE certification indicates that the isolators meet the specified safety criteria and conform to European safety standards, ensuring their reliability and functionality in diverse applications.
• Canadian Standards Association (CSA): This certification guarantees that digital isolators adhere to Canadian safety regulations and standards, ensuring their reliability and safety in electronic systems deployed across Canada.
• China Quality Certification (CQC): The China Quality Certification GB 4943.1-2022 emphasizes conformity assessment and quality control in audio/video, information, and communication technology equipment.

These certifications collectively provide manufacturers, engineers, and consumers with the confidence that digital isolators have undergone comprehensive testing and comply with stringent safety measures, contributing to the overall safety and reliability of the electronic devices and systems in which they are utilized across global markets.

Features of digital isolators vs. optocouplers

Traditionally, the isolated transfer of digital signals has been carried out using optocouplers. These devices harness light to transfer signals through the isolation barrier, using an LED and a photosensitive device, typically a phototransistor. The signal on one side of the isolation barrier turns the LED on and off.

When the photons emitted by the LED impact the phototransistor’s base-collector junction, a current is formed in the base and becomes amplified by the transistor’s current gain, transmitting the same digital signal on the opposite side of the isolation barrier.

Digital isolators provide four key features that make them better than optocouplers in smart home devices:

• Low-power consumption: Digital isolators don’t need to supply a light source, and instead use more efficient channels to transfer the signal. This makes digital isolators ideal for battery-powered devices such as smart thermostats and security sensors.
• High-speed data transmission: Phototransistors have long response times, which limits the bandwidth of optical isolators. On the other hand, digital isolators can transfer signals much quicker, enabling fast and reliable communication between smart home devices and control systems.
• Low electromagnetic interference (EMI): EMI can interfere with electronic devices in the home. By adopting capacitive isolation technology, digital isolators are more immune to EMI.
• Wide operating temperature range: This makes digital isolators suitable for a variety of robust environments, including outdoor applications.

Types of digital isolation

There are two types of digital isolation that can be implemented: magnetic isolation and capacitive isolation. Magnetic isolation relies on a transformer to transmit signals, while capacitive isolation uses a capacitor to transmit signals across the isolator, which creates an electrical barrier. This barrier prevents direct current flow and provides isolation between the input and output circuits.

Capacitive isolation is the most commonly used method due to several advantages.

• Higher data rates: Compared to magnetic isolation, the higher data rates of capacitive isolation can be used for applications that require fast and reliable communication.
• Lower power consumption: Compared to magnetic isolation or optical isolation, capacitive isolation typically consumes less power, making it a more energy-efficient choice for battery-powered devices.
• Smaller size: Capacitive isolators are typically smaller than magnetic isolators or optical isolators, which eases their integration into small electronic devices.
• Lower cost: Capacitive isolators are typically less expensive than optical isolators, which rely on expensive optoelectronic components like LEDs and photodiodes.
• Higher immunity to EMI: Compared to magnetic isolation, capacitive isolation is less susceptible to EMI, resulting in capacitive isolation being a more reliable choice in noisy environments.

Figure 4 shows a comparison of traditional optical isolation compared to magnetic and capacitive isolation.

Figure 4 Capacitive isolation offers key advantages over optical isolation and magnetic isolation. Source: Monolithic Power Systems

The type of digital isolation used depends on the application specifications, such as the required data rate, temperature range, or the level of electrical noise in the environment. Figure 5 shows a block diagram of a smart refrigerator, which requires three digital isolators.

Figure 5 The block diagram of a smart refrigerator that requires three digital isolators. Source: Monolithic Power Systems

Applications of digital isolators in smart home devices

Providing electrical isolation between the control system and appliance circuitry is crucial to ensure user safety as well as to protect smart home devices from outside interference or hacking. Some examples of smart home devices that integrate digital isolators include smart lighting systems, smart security systems, smart thermostats and smart home entertainment systems, which are described in further detail below.

Smart lighting systems

In smart lighting systems, digital isolators provide isolation between the control system and the high-voltage lighting circuitry. This prevents the user from coming into contact with high-voltage electrical signals.

Smart security systems

In smart home security systems, digital isolators provide isolation between the control system and the sensors or cameras. Isolating the sensitive control circuitry from the outside world addresses concerns regarding outside interference to the security system.

Smart thermostats

In smart thermostats, digital isolators provide isolation between the control system and the heating or cooling circuits. This minimizes damage to the control system from high-voltage or high-current signals in the heating or cooling circuits.

Smart home entertainment systems

In smart home entertainment systems like smart speakers, digital isolators provide isolation between the control system and the audio or video circuits. This achieves high-quality playback by preventing interference or noise in the audio or video signals.

George Chen is product marketing manager at Monolithic Power Systems (MPS).

Tomas Hudson is applications engineer at Monolithic Power Systems (MPS).

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The post Integrating digital isolators in smart home devices appeared first on EDN.

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I started tinkering with transistors because it’s what I am mostly learning this semester. First I tried to control output using the PWM pin from my RPi. After that I got the idea of building an RC car and doing the input to the motor from scratch. My first working test is an H-bridge using 4 npn and 2 pnp transistors with modulation through the Q2 and Q4 npn. Right now I can generate a rectangular wave. The 2 LEDs are in opposite directions, so a positive voltage turns one and a negative the other. The This week I want to bring it to uni and test the sinusoidal generation and efficiency with the oscilloscope. submitted by /u/InfernityZarroc [link] [comments]