
Show HN: USB PD Stand-Alone Sink Controller - oxplot
https://blog.oxplot.com/usb-pd-standalone-sink-controller/
======
ermir
This is quite cool! Any PCB designer that needs a lot of power should just use
this design and hopefully the world will eventually settle on using micro USB
for low power and USB PD for up to 100W. I am currently thinking of making a
device that has a PCB, and one of my key requirements is the use of micro USB
(5V 500mA) precisely because designing power circuits and distributing DC
adapters is a major cost.

~~~
btgeekboy
It’s kinda funny how the world has converged on USB as a universal charging
standard. I have a tote full of old AC/DC transformers in the garage; I used
to save them as you never knew when you’d need one of a specific
connector/voltage/ amperage combo. Now they’re somewhat obsolete.

~~~
benburleson
Aside from the many, many different sizes, I really miss barrel jacks for
charging. Like USB-C, there is no wrong way to plug it in, but the connection
always feels solid.

I currently have to wiggle my USB-C and find the right angle to achieve "rapid
charging," and if it moves too much it just falls out.

Feels like we've gone backwards in physical connection reliability.

~~~
maxerickson
Do USB-C connectors get packed with lint?

I had a USB micro phone stop charging and it ended up being lint/dust packed
in the connector.

~~~
artiscode
They do. I started seeing my phone not getting fully charged during the night
and driving on a bumpy road would make the screen turn on and off. Took me a
while to realize that a small lint ball from inside my pocket had made it into
the USB C socket of my phone. It was small enough not to be overly evident.
Few minutes with a toothpick and it's good as new!

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chx
So... [https://www.tindie.com/products/clarahobbs/pd-buddy-
sink/](https://www.tindie.com/products/clarahobbs/pd-buddy-sink/) like this,
right?

Now, I saw a ThinkPad plug in the blog post. Lenovo sells this ready made.
ttps://support.lenovo.com/us/en/accessories/acc500104

Search for 4X90U45346 to find purchase links. Two ideas:

US: [https://www.cdw.com/product/lenovo-usb-c-to-slim-tip-
cable-a...](https://www.cdw.com/product/lenovo-usb-c-to-slim-tip-cable-
adapter-power-connector-adapter/5587204)

Elsewhere: [https://www.ebay.com/itm/Usb-C-To-Slim-Tip-Cable-Adapter-
NEW...](https://www.ebay.com/itm/Usb-C-To-Slim-Tip-Cable-Adapter-
NEW/303263410323)

~~~
wlesieutre
Only 45W, so OP’s will work better for large laptops, assuming there are big
thinkpads using this connector (I have no idea if that’s the case)

~~~
chx
The slim plug is available on adapters from 45w to monster 230w (that RTX 5000
in the P53 alone eats 110W, the CPU is _nominally_ 45W but in reality it's oh-
my-god then there's a screen to power, typically 4K and we didn't even start
charging our battery, previously only the 17" laptops needed 230W at full
config, the basic adapter is "only" 170W). The plug center leg is for wattage
detection, there's a resistor to ground and the size of the resistor tells the
laptop how many watts can it draw safely.

------
ebg13
Thought this would be about roboticizing my kitchen faucet. Had to dig to
find:

> _What is it? Ever thought of (re-)using your USB-C charger (like Macbook 's)
> to power other devices? If so, this is the board for you._

~~~
cgranier
I was extremely confused as well... That he also doesn't really explain what
he was doing didn't help. ¯\\_(ツ)_/¯

------
SyncOnGreen
Neat project - I was looking for something similar for powering various bits
of electronics and stumbled upon WEB PDC001 (can be found on Aliexpress) cable
which is basically programmable USB-C cable with DC barrel jack. Works great
with TS-100 soldering iron powered using generic PD phone charger. The only
issue with it - software for programming it is Windows only and it isn't
translated to English.

~~~
chx
If you figured the sw out, care to publish a blog post about it?

~~~
SyncOnGreen
I tried reverse-engineering the USB protocol but quickly moved onto another
project. Project is on GitHub [https://github.com/JaCzekanski/pdc-
control](https://github.com/JaCzekanski/pdc-control)

Small correction: the software itself is in English but the documentation (and
firmware files) is in Chinese.

------
splitbrain
Now, can anyone recommend a small, lightweight PD charger that ideally also
has 3 to 4 "normal" USB ports, provides 100 Watts and has an EU socket
connector? I would love to carry a single power supply for charging all my
devices when travelling.

~~~
notpeter
Anker PowerPort Adam PD4 100w [1] is likely the closest. It has two USB-C PD
and two USB Type A. It splits that 100w amongst attached devices, giving the
full 100w to a single USB-C PD port (20V @ 5A) or sharing the 100w across
multiple devices, for example:

    
    
      * Macbook Pro (45w USB-C 15V @ 3A)
      * iPhone XR (30w USB-C 15V @ 2A)
      * Battery Pack (12w USB-A 5V @ 2.4A)
      * Apple Watch (12w USB-A 5V @ 2.4A)
    

Or the simpler everyday use: 15in Macbook Pro (87w) + USB-A (12w). It uses a
standard IEC-320-C7 cable for power (two pin, round hole) so getting local
cables anywhere should be easy.

MSRP is $99.99. Availability is a tight, but it does exist. A few sites have
reviewed it and there's at least one teardown on the web.

[1]: [https://amzn.to/35EB0pe](https://amzn.to/35EB0pe)

~~~
splitbrain
This looks promising, thanks. Still a bit on the heavy/large side. Is this
using GaN tech already?

~~~
GoMonad
I've been looking at the innergie chargers. They use GaN.

I've been looking at this once since its so small.

[http://www.myinnergie.com/sg/product/136](http://www.myinnergie.com/sg/product/136)

~~~
anbotero
I didn't like a review saying it's small because some components were left in
the cable and hence not all USB-C cables work. It might be an outlier/mistake,
but yeah...

I have been using this RAVPower 61W Wall Charger for some weeks now, and it's
GaN:
[https://smile.amazon.com/dp/B07TC53ZYD](https://smile.amazon.com/dp/B07TC53ZYD)

------
dijit
This is incredible, something like this becoming mass market would remove the
issues we have of older laptops not having easily replaceable power bricks.

~~~
mschuster91
This design does lack a configurable dc/dc voltage regulator, I've seen
laptops with anything between 12-24V... any idea for a circuit?

~~~
userbinator
Due to component tolerances, laptops aren't that picky about what voltage they
need; capacitors with 16V and 25V max ratings have basically created two
ranges, 9-12V and the far more common 18-20V:

[https://news.ycombinator.com/item?id=12618406](https://news.ycombinator.com/item?id=12618406)

I find the other comment about a programmable output voltage in 50mV
increments a little amusing, since 50mV of 5V is 1% and of 20V is 0.25%. To
maintain the former level of regulation over changing loads would already
require a _very_ expensive and powerful supply with remote sense, while the
latter is basically voltage reference territory.

~~~
sokoloff
Voltage refs are more typically 2 orders of magnitude better than that.

~~~
userbinator
Better references, yes, but 0.25% is typical of a cheap reference like a '431.

~~~
sokoloff
I stand corrected; thank you. I am genuinely surprised to learn that those are
called voltage references, but that is an accepted industry term.

------
sp332
What kind of car USB charger outputs 100W?

~~~
oxplot
Most cars provide >120watt power through the cigarette lighter socket. It's
just that no one has yet made a USB charger with that output power presumably
because no single device requires it yet.

------
solarkraft
What is required for this to act as a power supply? I'm thinking about
building a power bank.

~~~
oxplot
This board can only consume power. ST sells chips which act as USB PD supply
but they're only interface chips. You'll need a DC-DC converter and charger
circuit as well which is usually complicated with dozens of components and
tricky layouts.

------
botto
So you say you set the voltage and current requirements once in the software,
but looking at the data sheet it can be reprogrammed?

Do you mean you set it and it works between power cycles?

Otherwise you have to be careful and set the values you need first time I
guess.

~~~
tastroder
> Do you mean you set it and it works between power cycles?

Yes, the article stresses that explicitly. That's in section 5.1 of the
datasheet I believe.

------
mschuster91
Wow, thanks for the recommendation for pcb.ng. Can they really source every
part available on digikey, mouser etc., including microprocessors and ICs?

~~~
oxplot
Yes, just sign up and create a project and enter some parts. It tells you
instantly the cost of each.

~~~
penagwin
> MELFs. Not only do we handle them, but we get a juvenile kick out of the
> name.

Okay I love them already. Who doesn't love a little sense of humor?

------
ones_and_zeros
I read the blog post but it's still not clear what this is or its for? Is it a
usb c port for laptops without them?

~~~
MisterTea
In electronics terms, sink means a device which consumes current. The opposite
is aptly named source. So a source supplies a sink.

The 100W 20V USB-C power standard requires a negotiation protocol to tell a
source what the sink requires. This is to ensure a source is not overloaded or
a sink fed the wrong voltage. So this article explains how the author used an
off the shelf USB-C power chip to talk to a standard USB-C power source and
request enough power to charge their laptop (the sink).

