USB Power Delivery is widely considered to be a good thing. It’s become relatively standard, and is a popular way for makers to easily power their projects at a number of specific, useful voltages. However, what you may not know is that it’s possible to get much more variable voltages out of some USB chargers out there. As [GreatScott!] explains, you’ll want to meet USB-C PPS.
PPS stands for Programmable Power Supply. It’s a method by which a USB-C device can request variable voltage and current delivery on demand. Unlike the Power Delivery standard, you’re not limited to set voltages at tiers of 5V, 9V, 15V and 20V. You can have your device request the exact voltage it wants, right from the charger. Commercially, it’s most typically used to allow smartphones to charge as fast as possible by getting the optimum voltage to plumb into the battery. However, with the right techniques, you can use PPS to get a charger to output whatever voltage you want, from 3.3 V to 21 V, for your own nefarious purposes. You can choose a voltage in 20 mV increments, and even set a current limit in 50 mA increments. Don’t go mad with power, now.
However, there’s a hitch. Unlike USB PD, there isn’t yet a whole ecosystem of $2 PPS breakout boards ready to gloop into your own little projects. As [GreatScott!] suggests, if you want to use PPS, you might want to take a look at the AP33772S IC. It’s a USB PD3.1 Sink Controller. You can command it over I2C to ask for the voltage and current you want. If that’s too hard, though, [CentyLab] has a solution on Tindie to get you going faster. It’s also got some exciting additional functionality—like USB-C AVS support. It offers higher voltage and more power, albeit with less resolution, but chargers with this functionality are quite obscure at this stage.
We’ve actually touched on PPS capability before in our exploration of the magic that is USB-C Power Delivery. Video after the break.
[Thanks to Keith Olson for the tip!]
This could make a nice bench voltage supply. 0-10,0-5, 2-10, all from a wall wart or usb c powerbank. Can anybody think of way of getting that resolution down to single digit mA to handle 4-20mA? A device like that would make a lot of control techs very happy. Most of the adjustable signal generators are much larger, use 9v batteries, and can’t make 20vdc to provide the utility power for Air velocity or pressure transmitters.
4-20mA is its own specific thing, just use a regular old op amp and mosfet current source as a separate output.
Would it need safety certifications to be useful to techs, or can these systems be trusted to actually be low voltage?
If you peruse Aliexpress you’ll find several USB-C PD mini variable PSUs. For about the same price, you could get an AC powered 1000w 0-100v variable PSU, so you’re paying quite a bit for the novelty.
Featured on Hackaday four months ago:
https://hackaday.com/2024/11/19/power-supply-with-benchtop-features-fits-in-your-pocket/
Uhhhh. I’ve known about it for almost 4 years.
👍
Cool.
Would you be so kind to make a list of the other things you also already know and send it to Hackday so that they could adjust the articles to your specific needs. Please order the list on the number of years you already know specific items so that an appropriate filter can be applied.
Indeed, and Id think the list of unknown things would be quite small, so perhaps include this too and on the off chance someone has solved where the universe has come from it can be added to the known list as well.
https://xkcd.com/1053/
😂
Can you please provide a link to the article or video where you shared your knowledge in order to help benefit others? That would be much appreciated.
Can I have your autograph?
For a second I thought it was Pulse Per Second so we could have sweet frequency standard syncing. Shows where my head is. Programmable power supply is cool too, seems decadent given how rad PD is already.
Same here, my instant reaction was “that is something odd, but extremely useful in certain edge cases”. But then I read it was just about power again. Seems that USB is mostly about 1000 different ways to deliver power these days.
“get much more variable voltages out of some USB chargers out there”
Doesn’t sounds like a widely supported feature.
All the good USB PD supplies I’ve bought over the last several years have supported PPS. It’s not at all hard to find.
The question is do they advertise this feature to the public?
I ask as the new Anker powerbank I just bought has distinct voltage levels on its label but no range. Even browsing Amazon and AliExpress it was not easy to find, and yet here you are saying that it’s common.
They do, in the voltage list printed on the device, you should also see a voltage range and current specified for PPS mode. Many modern phones use PPS for the highest charging speed (like Samsung)
I’ve also seen it’s possible to manage this with a couple microcontroller pins and resistors, but documentation is kind of scarce. And while wall-chargers might be a little iffy, I think it’s very common in battery packs with USB-C variable-voltage output (especially if it explicitly mentions an odd voltage like 4.5V)
This might also be an alternative: https://github.com/manuelbl/zy12pdn-oss
It seems to work quite well – I am using it myself to get 18V output for a my son’s model railway from a USB-C power supply.
The only reason I know about PPS is because it’s the only way to get 12v, yes 12 volts, one of the most popular supply voltages for small electronics, out of a USB-PD charger. I will never stop complaining about this.
The change to remove 12V from required voltages came w/ a change proposed by a certain fruit company back in 2015 in an attempt simplify power supply requirements and consumer understanding of voltage compatibility based on just the max wattage rating of the supply.
I question this as the USB PD trigger boards I got from AliExpress support 12V. Even my powerbank and wall charger advertise this a one of their standard voltage levels.
Am I missing something?
Fortunately PPS is fairly common so a lot of equipment can do 12v but it’s not one of the voltages required for the base USB-PD standard. It even says so in the article. “Unlike the Power Delivery standard, you’re not limited to set voltages at tiers of 5V, 9V, 15V and 20V.” You seem to have gotten lucky with the equipment you have on hand. I have several USB-PD wall chargers that only do 5, 9, 15, 20. Heck Dell was pulling shenanigans for a while with laptop chargers that would do 5v or 20v and nothing else.
I assumed it was polyphenylene sulfide because my phone gets so hot
Samsung used this technology in their flagship phones for 5 years. That’s why their 45W charger isn’t 50% slower than chinies 90W chargers.
I’ve anker ace 313 and it can charge my device really fast.
This is super useful. Programmable DC-DC converter boards are pretty expensive.
I’m not an expert but my view of USB C charging standards is that PPS is the last charger you’ll ever need to buy. I realized this when I discovered Samsung using this on tablets many years ago, and now the phones too. The brandimg they use being “Super Fast Charging.” I’m happy that my last three purchases provide PPS, two of which still include the dumber and still important A ports for always 5V types of devices that cannot change on a PPS port. Extra PD chargers is good to a point if you have multiple devices to juice and might not have a 200W+ PPS charger.
Now after reading this article I find it interesting that PPS can have another use.