High current with USB 3 cable split on PCB?

Other Hardware General Electronics
1

I want to control a high current LED (up to 1.4 A) via a Nano from USB 3 with 5 V and up to 1.5 A. I was advised to consider a N-MOSFET, which sounds like good advice.

But: I like to power the Nano the recommended way (for beginners): With the USB Mini-B connector. What I thought is, to use a custom male PCB USB Mini-B connector:
https://www.mouser.de/ProductDetail/TE-Connectivity/1734205-1?qs=o4qE4s2E%252BcwHLCQYxSm%252B8w%3D%3D

(I get already a headache only thinking about soldering that tiny connector.)

Where I split the voltage and ground into two sources, so that the USB source powers the high current LED directly, and the Nano controls only the MOSFET (or NPN transistor-base), regulating the power for the LED.

Does this make sense?
Do I need even a N-MOSFET if I do it this way, won't be a transistor enough?
Is there an even easier way?

2

To control anything more than a few 10's mA, you need a transistor. A FET is normally what's used for that.

What Nano do you got?

3

Maybe take a picture to post here of your hand drawn circuit CLEARLY labelled.

4

How do you plan on doing that. Post an annotated schematic showing what you want. If you have 5V you can probably drive the LED with a MOSFET but without know what LED you are using and what its Vf is the circuit cannot be completed.

Try this link it will be easier then soldering: https://www.aliexpress.us/item/3256806272462668.html

1 Like
5

You cannot.
Without USB PD, USB 3.0, 3.1 max current is 900mA

6

Thanks for all the answers.

@sonofcy
Here is the labeled circuit:

StrongLED
StrongLED855×875 7.65 KB

@ledsyn
It's for an "Arduino Nano", w/o anything extra. The NPN-Transistor Model-Name is just a placeholder, I've to find one for strong currents, but I don't think I need super-fast switch times. I'm not so keen on using N-MOSFETs, since I'm a beginner and not sure how to even use that correctly.
The switch SW1 exists so I can program the Arduino w/o interference from the high currents flowing through the LED circuit part.

@gilshultz That sounds great, unfortunately I can't open that link in my region. Can you tell me the keywords I must search for?

@jim-p Yes and no. You are correct: The specification clearly states that it's not OK to draw that much current. In practice though... Let's say: My own experience tell otherwise. It's not easy to find tests on how modern USB ports and powered hubs perform when devices demand too much load. Most results just quote the official specifications. However: The test I found showed that all random chosen USB devices delivered reliably much higher current than 900 mA.
And this nice Linus TechTips Video explains what common practice is: Most manufacturers just want to satisfy the customer and deliver as much power as needed. Even ignoring power negotiations for Battery Charging (although I think: Power Delivery is another story, that could become dangerous).
And: I have here a high current LED connected to a powered USB 2 hub, w/o any problems. It doesn't seem to have any logic, negotiating more than the official 100 mA. Still: The LED draws so much power, it's getting super hot (by design), extra glued onto a heatspreader. It's part of a lamp from a popular Etsy shop, where nobody seems to have a problem powering the LED via a USB-A connector. (I myself would not sell something like that, but in private it's my own risk.)

7

I'm quite familiar with the shoddy design practices of most PC/laptop manufacturers.

As long as you know.

BC847 is only good for 100mA
I would use an IRLZ44N

8

I do not remember but this is what the item is: USB Type C PD Converter 5V 9V12V Power Adapter PD6W USB Type-C to DC Jack Charging Cable for HP/DELL/Asus Laptops Router

9

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.