Lessons Learned From A High-Voltage Power Supply

January 18, 2024 by 8 Comments

When you set out to build a 60,000-volt power supply and find out that it “only” delivers a measly 50,000 volts, you naturally have to dive in and see where things can be improved. And boy, did [Advanced Tinkering] find some things to improve.

First things first: if you haven’t seen [Advanced]’s first pass at a high-voltage supply, you should go check that out. We really liked the design of that one, and were particularly impressed with the attention to detail, all of which seemed to be wisely geared to the safe operation of the supply. But as it turns out, the margin of safety in the original design wasn’t as good as it could be. Of most concern was the need to physically touch the supply to control it, an obvious problem should something go wrong anywhere along the HV path, which includes a ZVS-driven flyback and an epoxy-potted Crockcroft-Walton voltage multiplier.

To make things a little more hands-off, [AT] added a pneumatically actuated switch to the supply, along with some indicator lights to help prevent him from leaving the supply powered up. He also reworked the low-voltage DC supply section, replacing a fixed-voltage supply and a DC-DC converter with a variable DC supply. This had the side benefit of providing a little bit more voltage to the ZVS driver, which goosed up the HV output a bit. The biggest change, though, was to the potted part of the HV section, which showed signs of arcing to the chassis. It turns out that even at 100% infill, 3D printed PLA isn’t a great choice for HV projects; more epoxy was the answer to that problem. Along with rewinding the primary on the flyback transformer, the power supply not only hit the 60-kV spec, but even went a little past that — and all without any of that pesky arcing.

We thought [Advanced Tinkering]’s first pass on this build was pretty slick, but we’re glad to see that it’s even better now. And we’re still keen to see how this supply will be put to use; honestly, the brief teaser at the end of the video wasn’t much help in guessing what it could be.

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Tearing Down And Improving A Professional Power Supply

July 11, 2023 by 11 Comments

[OZ2CPU] has an HP power supply that is about 30 years old. It looks brand new, though, and has three outputs and includes tracking for the adjustable positive and negative supply. After a quick demo of the unit’s features, he tears it all down so we can see inside. You can catch the video below.

Some similar supplies offer a 10-turn adjustment knob, but this one doesn’t. Inside is a beefy transformer and quite a few through-hole components. There was room to change the main adjusted pot to a 10-turn unit, so he made the mod.

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Linear Power Supply’s Current Limiter Is A Lesson In Simplicity

June 5, 2023 by 5 Comments

Here at Hackaday we really like to feature projects that push the limits of what’s possible, or ones that feature some new and exciting technology that nobody has ever seen before. So what’s so exciting about this single-voltage linear power supply? Honestly, nothing — until you start looking at its thermally compensated current limiting circuit.

This one is by [DiodeGoneWild], who you’ve really got to hand it to in terms of both the empirical effort he went through to optimize the circuit, as well as the quality of his explanation. The basic circuit is dead simple: a transformer, a full-wave rectifier, an LD1085 adjustable regulator — a low-dropout version of the venerable LM317 — and associated filter caps and trimmer pot to adjust the output between 2.2 and 5.5 volts.

The current limiting circuit, though, is where things get interesting. Rather than use an op-amp, [DiodeGoneWild] chose a simple discrete transistor current-sense circuit. To make it less susceptible to thermal drift, he experimented with multiple configurations of resistors and Schottky diodes over a wide range of temperatures, from deep-freeze cold to hair-dryer-in-a-box hot. His data table and the resulting graph of current versus temperature are works of art, and they allowed him to make sensible component selections for a fixed 250-mA current limit with a reasonably flat thermal response.

As for construction, it’s all classic [DiodeGoneWild], including a PCB with traces ground out with a Dremel and a recycled heat sink. He also dropped a couple of interesting build techniques, like adding leads to turn SMD tantalum caps into through-hole components. The video below shows all the build details along with the exhaustive breadboard testing.

From taking on a potentially risky magnetron teardown to harvesting lasers from headlights, there’s always something to learn from a [DiodeGoneWild] video.

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High Voltage Power Supply From USB

April 30, 2023 by 14 Comments

Those who work in different spaces may have different definitions of the term “high voltage”. For someone working on the GPIO pins of a Raspberry Pi it might be as little as 5 volts, someone working on a Tesla coil might consider that to be around 20 kV, and an electrical line worker might not reference something as HV until 115 kV. What we could perhaps all agree on, though, is that getting 300 volts out of a USB power supply is certainly a “high voltage” we wouldn’t normally expect to see in that kind of context, but [Aylo6061] needed just such a power supply and was eventually able to create one.

In this case, the high voltages will eventually be used for electrophoresis or electrowetting. But before getting there, [Aylo6061] has built one of the safest looking circuits we’ve seen in recent memory. Every high voltage part is hidden behind double insulation, and there is complete isolation between the high and low voltage sides thanks to a flyback converter. This has the benefit of a floating ground which reduces the risk of accidental shock. This does cause some challenges though, as voltage sensing on the high side is difficult while maintaining isolation, so some clever tricks were implemented to maintain the correct target output voltage.

The control circuitry is based around an RP2040 chip and is impressive in its own right, with USB isolation for the data lines as well. Additionally the project code can be found at its GitHub page. Thanks to a part shortage, [Aylo6061] dedicated an entire core of the microprocessor to decoding digital data from the high voltage sensor circuitry. For something with a little less refinement, less safety, and a much higher voltage output, though, take a look at this power supply which tops its output voltage around 30 kV.

A Particularly Polished ATX Bench Power Supply

August 18, 2022 by 43 Comments

Let’s be real, yanking the ATX power supply out of an old desktop computer and turning it into something you can use on the workbench isn’t exactly an advanced project. In fact, you could probably argue it’s one of the first DIY builds a budding electronic hobbyist should tackle — after all, you’re going to need a reliable bench supply if you want to do any serious work anyway.

But of course, there’s a big difference between doing the minimum and really giving something your all, and we think this ATX bench supply from [Steve Thone] of The Neverending Projects List is a phenomenal example of the latter. It not only looks impressive, but it’s been tricked out with plenty of bells and whistles to make it as capable as possible. What was once a basic 230 watt PSU pulled from an old Dell is now a piece of gear that any hacker or maker would love to have in their collection. Continue reading “A Particularly Polished ATX Bench Power Supply” →

Powering Up With USB: Untangling The USB Power Delivery Standards

September 16, 2021 by 37 Comments

Powering external devices directly from a PC’s I/O ports has been a thing long before USB was even a twinkle in an engineer’s eye. Some of us may remember the all too common PS/2 pass-through leads that’d tap into the 275 mA that is available via these ports. When USB was first released, it initially provided a maximum of 500 mA which USB 3.0 increased to 900 mA.

For the longest time, this provided power was meant only to provide a way for peripherals like keyboards, mice and similar trivial devices to be powered rather than require each of these to come with its own power adapter. As the number of  computer-connected gadgets increased USB would become the primary way to not only power small devices directly, but to also charge battery-powered devices and ultimately deliver power more generally.

Which brings us to the USB Power Delivery (USB-PD) protocol. Confusingly, USB-PD encompasses a number of different standards, ranging from fixed voltage charging to Programmable Power Supply and Adjustable Voltage Supply. What are the exact differences between these modes, and how does one go about using them? Continue reading “Powering Up With USB: Untangling The USB Power Delivery Standards” →

Turning A Bad Bench Supply Into A Better Bench Supply

December 1, 2019 by 24 Comments

‘Tis the season for dropping hints on what new doodads would make a hacker happy, and we have to admit to doing a little virtual window shopping ourselves. And as a decent bench power supply is on our list, it was no surprise to see videos reviews that the hive mind thinks will help us make a choice pop up in our feed. It’s a magical time to be alive.

What did surprise us was this video on a mashup of two power supplies, both of which we’ve been eyeing, with the result being one nicely hacked programmable bench PSU. It comes to us courtesy of [jeffescortlx], who suffered with one of those no-name, low-end 30V-5A bench supplies that has significant lag when changing the settings, to the point that it’s difficult to use, not to mention dangerous for sensitive components.

So he got a hold of a Riden RD6006 programmable buck converter, which is something like those ubiquitous DPS power supply modules we’ve seen so much of, only on steroids. The Riden takes up to 70V input and turns it into a 0-60V output at up to 6 amps, at constant current or constant voltage. It also just happens to (almost) fit as a replacement for the faceplate of the dodgy old supply. A few SMD resistors simulate the original front panel pots being pegged so that the supply outputs maximum voltage and current, and a little finagling with the case and fan was needed to fit everything up, but the finished product actually looks really good, and fixes all the problems of the original.

We love this hack, and may well cobble this together for our bench.

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