I have a lot of 19V 90W 130W, 180W, even 230W Power adapters, with 5.5x2.5 , 7.4x5.0, 5.0x3.0 plugs. PD adapters are too overpriced and the Type C connector is too flimsy.
1 Like
For me USB C power is a huge plus. One less thing I have to bring around, also the port can be used for more than just power. Since the expansion cards protect the ports of the mainboard, if you wear out a USB C expansion port you can just get a new one as they are relatively inexpensive. It takes all of the worry out of using your ports. I love it.
That said if you want to put together an expansion card with a breakout barrel connector, more power to you! That would be kind of cool!
6 Likes
I think the main problem comes with PD protocols, making a 48V5A(or 20V5A) passthrough impossible. A PD certified must not output without negotiation and must be able to output the lowest level i.e. 5V3A therefore you must put a DC to DC converter, a PD capable negotiator and a 48V5A(or 20V5A) e-marker (make the computer believe the “cable” is also certified. It’s very difficult if not impossible to put all these things into a expansion card.
The complexity of all this is to make sure users with zero experience are able to plug and play. I have a laptop with a power rating of 19.5V7.7A and I use a DC to DC converter to output that and using the battery pack of my e-bike as the power source. I do it all the time during field work. However the majority of the users don’t know how to do this safely so all the work has to be done by the developers.
the system don’t even have to be this complex like USB PD. Internal bus IS 20/19V
Really? If that’s the case, how does the laptop manage to boost 5V PD input all the way to 20V. AFAIK there a limit of the duty cycle of a boost converter unless you are using a different topology like a voltage doubler for example
The problem is that there isn’t a place to access it.
The expansion cards only lead to the PD system.
1 Like
5 to 20v is well within the range of what a regular boost converter can do.
You can find psu to pd adapters like this basically just a mosfet and a micro-controller that basically just advertised 20v, if the device requests it, it gives 20v otherwise nothing, at least to a tear-down I saw of one once. I don’t think it’s all that good an idea and pd power supplies are quite cheap and very versatile but it is possible especially if you only need to support a specific laptop and not all of them (and doesn’t really comply with the pd spec).
1 Like
That one costs 14$ and does 65W, and 65W PD charger costs 22$. The market is limited to framework users that already have a suitable barrel charger they want to keep using. So there is not much margin to go around and develop a PCB.
I don’t see it happening unless one of the potential buyers wants it hard enough to do it themselves.
I am very firmly in the it’s not a good idea camp but it is possible.
That is pretty much the only way this is happening
This opens up a ton of possibilities. It’s now possible to get the chip advertise 48V or 0V and be the first to power the FW16 at 240W when used with a 48V SMPS
That was always possible, not that it is a particularly good idea though.
negotiate through CC1 CC2 pin. not boosting from 5V to 20V.
To charge the battery using the 5v it negotiated using the cc pins it still needs to boost the voltage to a bit under 20v internally.
no no no, when we EE say “boost”, we mean this thing
also It is not “charger”, “charger” is inside the computer, it’s power adapter.
I am something of an EE myself (insert spiderman meme) and this is what I was talking about. (though with a second mosfet instead of the diode since it’s buck-boost while we are in technically correct mode). Not entirely sure what the no no no refers to exactly.
While I don’t think calling a laptop power brick “charger” is “wrong” since it is how the word is used by normal people you are of course technically correct.
I think one of you is talking about charging the laptop with a 5V phone charger - which requires a boost converter - while the other one is talking about telling the power brick to supply 20V.
I am talking about both since both were brought up XD, primarily the latter though (well not telling the power brick to supply 20v but telling the laptop to take 20v, or more likely 48v for this conversation).