Switching Regulators: Mistake Fixing For Dummies

Some time ago, while designing the PCB for the Sony Vaio replacement motherboard, I went on a quest to find a perfect 5 V boost regulator. Requirements are simple – output 5 V at about 2A , with input ranging from 3 V to 5 V, and when the input is 5 V, go into “100% duty” (“pass-through”/”bypass”) mode where the output is directly powered from the input, saving me from any conversion inefficiencies for USB port power when a charger is connected. Plus, a single EN pin, no digital configuration, small footprint, no BGA, no unsolicited services or offers – what more could one ask for.

As usual, I go to an online shop, set the parameters: single channel, all topologies that say “boost” in the name, output range, sort by price, download datasheets one by one and see what kind of nice chips I can find. Eventually, I found the holy grail chip for me, the MIC2876, originally from Micrel, now made by Microchip.

MIC2876 is a 5 V regulator with the exact features I describe above – to a T! It also comes with cool features, like a PG “Power good” output, bidirectional load disconnect (voltage applied to output won’t leak into input), EMI reduction and efficiency modes, and it’s decently cheap. I put it on the Sony Vaio board among five other regulators, ordered the board, assembled it, powered it up, and applied a positive logic level onto the regulator’s EN pin.

Immediately, I saw the regulator producing 3 V output accompanied by loud buzzing noise – as opposed to producing 5 V output without any audible noise. Here’s how the regulator ended up failing, how exactly I screwed up the design, and how I’m creating a mod board to fix it – so that the boards I meticulously assembled, don’t go to waste.

Some Background… Noise

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Catching The BOAT: Gamma-Ray Bursts And The Brightest Of All Time

Down here at the bottom of our ocean of air, it’s easy to get complacent about the hazards our universe presents. We feel safe from the dangers of the vacuum of space, where radiation sizzles and rocks whizz around. In the same way that a catfish doesn’t much care what’s going on above the surface of his pond, so too are we content that our atmosphere will deflect, absorb, or incinerate just about anything that space throws our way.

Or will it? We all know that there are things out there in the solar system that are more than capable of wiping us out, and every day holds a non-zero chance that we’ll take the same ride the dinosaurs took 65 million years ago. But if that’s not enough to get you going, now we have to worry about gamma-ray bursts, searing blasts of energy crossing half the universe to arrive here and dump unimaginable amounts of energy on us, enough to not only be measurable by sensitive instruments in space but also to effect systems here on the ground, and in some cases, to physically alter our atmosphere.

Gamma-ray bursts are equal parts fascinating physics and terrifying science fiction. Here’s a look at the science behind them and the engineering that goes into detecting and studying them.

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2024 Hackaday Superconference Speakers, Round One

Supercon is the Ultimate Hardware Conference and you need to be there! We’ve got a stellar slate of speakers this year — way too many to feature in one post. So here’s your first taste, and a reminder that Supercon will sell out so get your tickets now before it’s too late.

In addition to the full-length talks, we’ve got a series of Lightning Talks, so if you want to share seven minutes’ of insight with everyone there, please register your Lightning Talk idea now.

But Supercon has a lot more than just talks! The badge heavily features Supercon Add-Ons, and we want to see the awesome SAOs you are working on. There will be prizes, and we’ll manufacture four of our favorite designs in small batches for the winners, and make a full run for Hackaday Europe in 2025. Want to know more about SAOs? They’re the ideal starter PCB project.

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Hack On Self: Collecting Data

A month ago, I’ve talked about using computers to hack on our day-to-day existence, specifically, augmenting my sense of time (or rather, lack thereof). Collecting data has been super helpful – and it’s best to automate it as much as possible. Furthermore, an augment can’t be annoying beyond the level you expect, and making it context-sensitive is important – the augment needs to understand whether it’s the right time to activate.

I want to talk about context sensitivity – it’s one of the aspects that brings us closest to the sci-fi future; currently, in some good ways and many bad ways. Your device needs to know what’s happening around it, which means that you need to give it data beyond what the augment itself is able to collect. Let me show you how you can extract fun insights from collecting data, with an example of a data source you can easily tap while on your computer, talk about implications of data collections, and why you should do it despite everything.

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Where Do You Connect The Shield?

When it comes to polarizing and confusing questions in electronics, wiring up shields is on the top-10 list when sorted by popularity. It’s a question most of us need to figure out at some point – when you place a USB socket symbol on your schematic, where do you wire up the SHIELD and MP pins?

Once you look it up, you will find Eevblog forum threads with dozens of conflicting replies, Stackexchange posts with seven different responses plus a few downvoted ones, none of them accepted, and if you try to consult the literature, the answer will invariably be “it depends”.

I’m not a connector-ground expert, I just do a fair bit of both reading and hacking. Still, I’ve been trying to figure out this debate, for a couple years now, re-reading the forum posts each time I started a new schematic with a yet-unfamiliar connector. Now, of course, coming to this question with my own bias, here’s a summary you can fall back on.

Consumer Ports

Putting HDMI on your board? First of all, good luck. Then, consider – do you have a reason to avoid connecting the shield? If not, certainly connect the shield to ground, use jumpers if that’s what makes you comfortable, though there’s a good argument that you should just connect directly, too. The reason is simple: a fair few HDMI cables omit GND pin connections, fully relying on the shield for return currents. When your HDMI connection misfires, you don’t want to be debugging your HDMI transmitter settings when the actual No Signal problem, as unintuitive as it sounds, will be simply your shield not being grounded – like BeagleBone and Odroid didn’t in the early days. By the way, is a DVI-D to HDMI adapter not working for you? Well, it might just be that it’s built in a cheap way and doesn’t connect the shields of the two sockets together – which is fixable.

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Review: IFixit’s FixHub May Be The Last Soldering Iron You Ever Buy

Like many people who solder regularly, I decided years ago to upgrade from a basic iron and invest in a soldering station. My RadioShack digital station has served me well for the better part of 20 years. It heats up fast, tips are readily available, and it’s a breeze to dial in whatever temperature I need. It’s older than both of my children, has moved with me to three different homes, and has outlived two cars and one marriage (so far, anyway).

When I got this, Hackaday still used B&W pictures.

As such, when the new breed of “smart” USB-C soldering irons started hitting the scene, I didn’t find them terribly compelling. Oh sure, I bought a Pinecil. But that’s because I’m an unrepentant open source zealot and love the idea that there’s a soldering iron running a community developed firmware. In practice though, I only used the thing a few times, and even then it was because I needed something portable. Using it at home on the workbench? It just never felt up to the task of daily use.

So when iFixit got in contact a couple weeks back and said they had a prototype USB-C soldering iron they wanted me to take a look at, I was skeptical to say the least. But then I started reading over the documentation they sent over, and couldn’t deny that they had some interesting ideas. For one, it was something of a hybrid iron. It was portable when you needed it to be, yet offered the flexibility and power of a station when you were at the bench.

Even better, they were planning on putting their money where their mouth is. The hardware was designed with repairability in mind at every step. Not only was it modular and easy to open up, but the company would be providing full schematics, teardown guides, and spare parts.

Alright, fine. Now you’ve got my attention.

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Lithium-Ion Battery Hotswapping, Polarity, Holders

Everyone loves, and should respect, lithium-ion batteries. They pack a ton of power and can make our projects work better. I’ve gathered a number of tips and tricks about using them over the years, based on my own hacking and also lessons I’ve learned from others.

This installment includes a grab-bag of LiIon tricks that will help you supercharge your battery use, avoid some mistakes, and make your circuits even safer. Plus, I have a wonderful project that I just have to share.

Hot-swapping Cells

When your device runs out of juice, you might not always want to chain yourself to a wall charger. Wouldn’t it be cool if you could just hot-swap cells? Indeed it is, I’ve been doing it for years, it’s dead simple to support, but you can also do it wrong. Let me show you how to do it right!

Recently, a new handheld has hit the hacker markets – the Hackberry Pi. With a Blackberry keyboard and a colour screen, it’s a pretty standard entry into the trend of handheld Pi Zero-backed computers with Blackberry keyboards. It’s not open-source and the author does not plan to open-source its hardware, so I want to make it absolutely clear I don’t consider it hacker-friendly or worth promoting. It did publish schematics, though, and these helped me find a dangerous mistake that the first revision made when trying to implement LiIon battery hot-swap. Continue reading “Lithium-Ion Battery Hotswapping, Polarity, Holders”