Daisy chaining

[Anonymous]

Hi,

We are working on a application where we need to daisy chain up to 100 adjacent devices together with USB-C. This is for a collaborative robotics solution. Each robot will have a USB-C controller with an upstream and downstream USB-C port. The daisy chain is used for power and data, including images. The hope/goal is that we can provide power to one of the robots and all the other robots get their power/data via the daisy chain. Couple of questions:

1) What is the maximum number of USB-C devices/controllers that can be daisy changed together?

2) Assuming each robot consumes at most 30 Watts, will there be a limit on the number of devices that can be daisy chained via a single power outlet?

Apologies if these questions seem naive. We're trying to validate if USB-C is the right solution or whether we should use something else. I'm still ramping up on the USB-C spec.

If any of the experts have suggestions/ideas on how to go about solving this, it would be greatly appreciated.

Best,

Randy.

[ShifangZ_26]

Hi Randy,

1) What is the maximum number of USB-C devices/controllers that can be daisy changed together?

>> There are two Type-C controller for each robot which is responsible for power sink and data device, power source and data source.

2) Assuming each robot consumes at most 30 Watts, will there be a limit on the number of devices that can be daisy chained via a single power outlet?

>> The Type-C connector with Power delivery can be support up to 100W. If all of robot is bus powered, 100W/30W, there are only 3 can be supported. If it is self-powered, the number is not limited.

Best Regards,

Lisa

[Anonymous]

Hi Lisa,

Thanks for the quick response. Regarding #2, we would very much like to power all the robots from the same USB-C bus. Alas, due to space/cost reasons, we can't put a battery in each robot and also, we can't run 100 individual power cords from the wall outlet.

This may seem like an impossible question, but are there any techniques to "propagate" or "amplify" the power at each device (robot) so that every robot in the daisy chain can receive 30W? For example, while the entire 100 fleet of robots may draw 3,000W (100 x 30W), the 3,000W is distributed among the 100 robots.

I was reading the spec some more and there is a mention of "USB-C pass through charging". Could each robot "pass through" the power to the next robot?

Unfortunately, I don't know anything about power distribution/load schemes, so any other suggestions on how to solve the power requirements for our fleet of robots would be greatly appreciated.

In a nutshell, here is a diagram of the desired outcome, i.e. one power source feeding all 100 robots.

                    01          02           03           100

+------+         ['']           ['']            ['']            ['']

|Power| ---└[__]┘---└[__]┘---└[__]┘ ... └[__]┘

+------+          ||             ||            ||               ||

Thanks again for your help.

Randy.

[ShifangZ_26 · Accepted solution]

Hi Randy,

If one power source feeding all 100 robots, I could like to recommend you design two Type-C port on each Robert (Recommend CCG5 with dual ports), and the Type-C port is Dual Role port. If any one of Type-C port will plugged in and identified as power sink role, the other one will refresh to  power source only to supply power to other Robert.  So that you could connect them and charge them as your picture above.

Best Regards,

Lisa