Curious about current "thunderbolt" hub designs

[pullman]

Greetings  people

Let's see if I can explain this well. I am looking for a hub to use with my M1 MBA but am surprised to find rather few that offer thunderbolt connections. And some of those that do offer non-USB C connections for power. Like the OWC Thunderbolt Hub which is sort of portable but which for some inexplicable reason uses a round DC IN power brick and makes it less useful when mobile.

Many, even from known brands, are advertised as thunderbolt hubs but that's only because of the connection to the computer, not because they offer outgoing such ports for peripherals. True, there are several larger docks with thunderbolt ports but they are too big to bring in a bag.

Why is this? Is thunderbolt too difficult to implement in a small form factor like a hub perhaps? Or is it too expensive such that it's only realistic to put in a larger dock-sized device which anyway will be pricier than a smaller hub?

I know USB C ports' 10Gbps isn't particularly slow but it seems strange that not more hubs, which connect via thunderbolt, offer such ports for peripherals.

br
Philip

 

[PaulD-UK]

Thunderbolt in its V1, v2 and v3 iterations from 2011-16 had no 'hub' capability - traditionally that has been a USB1/2/3 thing.
Thunderbolt was an advancement on the old SCSI and Firewire protocols, based on daisy-chaining.

However when Intel introduced Thunderbolt 4, it wasn't an advancement of TB3 speeds, but a merging with the next generation of USB4, bringing the TB3 bandwidth or ~40Gbps to USB4, and adding the USB 'hub' feature to TB4 devices.

Because one on the main features of a Thunderbolt 3 dock has been to power a laptop through the USB-C cable, nearly all TB3/4 docks have a massive PSU:
The TB4 chipset itself needs ~100W just to power the dock's internal electronics, and another 100W is needed to power the laptop.
Then, every TB/USB port on the dock needs another 15W - each...
It all adds up.

If you design a mini-TB4 hub and don't power it with sufficient power to supply the 15W to each port, then any device you connect to the hub will disconnect from the host Mac if it needs power...
Which means no one makes/sells such a problematic device.

However, because so few Windows PCs have a full implementation of Thunderbolt, Intel did design a low power hub controller chip for use in bus powered hubs:
Full sized TB4/USB4 hubs use the 'Goshen Ridge' JHL8440 controller chip.
But they also produced a reduced power 'Hoover Ridge' JHL8140 chip, specifically for bus powered hubs.

What this loses is the higher power requirement, but what it also loses is ~40Gbps bandwidth passthrough...
So it can act as a hub for USB 3.x and Ethernet, USB 2 for audio etc, and provide two Alt-mode DP 1.4 video streams to drive monitors.
But there is no PCIe v3 passthrough, which is needed for 40Gbps SSDs etc.
Any SSDs will connect at 10Gbps.

Of course if you run it with no external power it will only allow low-powered devices to be connected - just like a bus powered USB 3.x hub.

There are a few products available that use Hoover Ridge, and a reddit teardown:

Sparkle TD-8140 USB4 Travel Dock Review & Teardown (Intel Hoover Ridge JHL8140 dock)

Introduction At Computex Taipei and other tech conferences earlier this year, new USB4 chipsets from RealTek and Intel were announced. The Sparkle TD-8140 USB4 travel dock is the earliest available…

dancharblog.wordpress.com

https://www.reddit.com/r/UsbCHardware/comments/16fgtdt/intel_hoover_ridge_jhl8140_usb4_endpoint_chip

https://www.reddit.com/r/UsbCHardware/comments/1drnozr/after_a_long_time_searching_i_finally_found_a

 

[pullman]

Hello Paul and thank you for taking the time to explain this in such detail to me. I have learnt a lot by your post. In particular I hadn't realised that the transition from TB3 to TB4 was a merger with USB4 and that TB4 chipsets are so very power hungry.

The question that comes to my mind, though, is why there aren't more products with 40Gbps thunderbolt downstream ports that rely on external power through a USB C connection. I suppose quite a few will bring a charger when travelling – and often a fairly powerful one – plus a USB C cable. That would avoid the need to bring a separate dedicated power brick while providing quite a bit of power to the hub. Seems an odd design choice (to me).

 

[PaulD-UK]

@pullman "...why there aren't more products with 40Gbps thunderbolt downstream ports that rely on external power through a USB C connection."

There are some Chinese brands of USB4 enclosures that have a power input port, but only for a simple external PSU or non-PD USB power.

Complexity, confusion about compatibility, and most importantly, cost must be the reasons no one does it this way. 😶

 

[pullman]

Apologies for the delayed reply. To me, the perfect device would be one that can (somehow) function as a hub when not connected to power, with corresponding lower speeds on its Thunderbolt ports, but which can be powered via a powerful-enough USB C charger and then offers full Thunderbolt speeds.

Perhaps the technology to allow such switching isn't here yet.

But it honestly baffles me that manufacturers like OWC, Plugable, Ugreen and Baseus keep using power adapters for their docks when they build hubs that can be powered by USB C chargers. I just don't understand this logic.

I suppose there is no chance that future Thunderbolt chipsets will be less power-hungry. I mean 100W for the TB4 chip seems a lot.

@pullman "...why there aren't more products with 40Gbps thunderbolt downstream ports that rely on external power through a USB C connection."

There are some Chinese brands of USB4 enclosures that have a power input port, but only for a simple external PSU or non-PD USB power.

Complexity, confusion about compatibility, and most importantly, cost must be the reasons no one does it this way. 😶

 

[PaulD-UK]

@pullman
"I mean 100W for the TB4 chip seems a lot."
That's a simplification. But the PSU's for my two TB3 docks are 180W and 155W, so I was giving a ball-park figure.
The simple three TB4 port + one USB 3.1 Gen 2 port TB4 hubs have a 20V@5.5A = 110W PSU.

Your problem is that no one is making your 'perfect device' that has a low power standby mode for low bandwidth use...
The market is for high bandwidth performance, with simple PSUs, which don't require an embedded computer to handle power demand.
USB PD is too new to be ubiquitous, except for direct connection to battery charge computers and smart phones.
People would have too many of the 'wrong' sort of USB-C PSU... 😶

EDIT: There is one class of hub that has viewed things the same way as you,
The docks that are appearing which are made to fit under the M4 mini...
Where they are unable to function because they are exceeding the available bus power from the mini, they allow a USB-C charger to be plugged into a USB-C port to power the dock's additional needs.

So it is possible something like that may appear for the MBP/MBA?

 

[pullman]

Thanks, yes I definitely understand that what I desire is a unicorn device and that market demand top whatever I as a lone internet user write in a forum. Still, thanks for having taken the time to reply.

@pullman
"I mean 100W for the TB4 chip seems a lot."
That's a simplification. But the PSU's for my two TB3 docks are 180W and 155W, so I was giving a ball-park figure.
The simple three TB4 port + one USB 3.1 Gen 2 port TB4 hubs have a 20V@5.5A = 110W PSU.

Your problem is that no one is making your 'perfect device' that has a low power standby mode for low bandwidth use...
The market is for high bandwidth performance, with simple PSUs, which don't require an embedded computer to handle power demand.
USB PD is too new to be ubiquitous, except for direct connection to battery charge computers and smart phones.
People would have too many of the 'wrong' sort of USB-C PSU... 😶

EDIT: There is one class of hub that has viewed things the same way as you,
The docks that are appearing which are made to fit under the M4 mini...
Where they are unable to function because they bare exceeding the available bus power from the mini, they allow a USB-C charger to be plugged into a USB-C port to power the dock's additional needs.

So it is possible something like that may appear for the MBP/MBA?

 

[drrich2]

But it honestly baffles me that manufacturers like OWC, Plugable, Ugreen and Baseus keep using power adapters for their docks when they build hubs that can be powered by USB C chargers. I just don't understand this logic.

I'm passing along an idea on this someone else mentioned in another thread, and expanding on the idea. Ever notice how there are many devices that use an external 'round DC IN power brick,' as you say, to supply electrical current to the device? Now, when you think about it, have you noticed the round DC insert for one device usually doesn't fit into most others? They might look superficially similar, but the round plug in piece diameter varies.

That way, the device always gets the proper charger characteristics, in voltage, current, wattage, etc...

That is so not true with USB chargers and cables. Even if you stick with USB-C, that charger might be 20W for charging iPhones, 45W for charging an iPad Pro, 60W for charging a notebook Mac, etc... And just because the side of the charger says '100W,' doesn't mean any one port can put out that much wattage.

Now look at the cables. What power delivery a USB-C cable is rated for varies widely, and never mind USB-C vs. Thunderbolt cables.

Another issue with USB-C chargers and cables is users might grab some cheap 'Brand X' product at the truck stop or similar and use that.

I get that, if you have a powerful charger and high power delivery cable, it might sound neat to have your new Thunderbolt hub get external power via USB-C cable, rather than you having to bring a separate power brick for it.

But look at it the way the manufacturer does. Who wants tech support contacts from people who don't understand their low wattage phone charger isn't delivering enough power, or that cute pink Brand X USB-C cable from the truck stop isn't rated for the needed wattage, etc...?

Sometimes you save yourself headaches if you leave the end user only one way to hook something up...the right way.

 

[drrich2]

I am looking for a hub to use with my M1 MBA but am surprised to find rather few that offer thunderbolt connections.

Many, even from known brands, are advertised as thunderbolt hubs but that's only because of the connection to the computer, not because they offer outgoing such ports for peripherals.

So you want more than 1 downstream Thunderbolt port, which rules out a Thunderbolt 3 hub or dock from what I understand, leaving you the option of TB 4 or 5. You mentioned the OWC Thunderbolt hub; did you see the CalDigit Thunderbolt 4 and 5 versions of their Element hub?