USB cooling pad causes USB-A port to die, requiring an eject and re-insert

Hi all,

I have a USB cooling pad (Targus AWE55US) that I put under my laptop to keep it cool. I’ve used this fan with my previous Dell laptops without issue for years. It connects to my laptop via USB-A.

I’ve noticed a strange problem with my Framework laptop where the USB fan will abruptly stop running. This usually happens after being connected to the computer for a few minutes. Further investigation reveals that the entire USB-A port is dead. The USB-A port is completely unresponsive if I try to plug a USB-A flash drive into it. The other USB-A port on the other side of my laptop continues to work fine. However, if I plug my USB fan into that other USB-A port, then it will exhibit the same behavior: the fan runs fine for a few minutes, then dies along with the entire USB-A port. The USB-A port works normally after I eject and re-insert it.

Other possibly relevant details:

  • It doesn’t seem to matter if I’m connected to wall power or running off battery – the USB-A port dies in both circumstances.
  • My laptop has two USB-C and two USB-A ports installed (one USB-A and one USB-C on each side).
  • My USB-A ports otherwise work normally – no issues with flash drives – they only seem to die when connected to the USB fan for a few minutes.
  • Keeping a USB flash drive plugged into a USB-A port for an extended amount of time does not cause the USB-A port to die (i.e., only the USB fan seems to cause it to die).

Has anyone else experienced this type of behavior? Any thoughts on what might be causing this issue?

Thanks!

I wonder if the fan is pulling too much current or something. Which OS is this under? If Linux, does the journal/syslog have anything interesting around that time?

3 Likes

If you’re linux running powertop would also be a good idea to get an estimate of the current pulled by the cooling pad.

I’m running Windows 10. I tried using USBDeview to get a power reading, but it wasn’t giving me anything when I connected the USB cooling pad.

I went out, bought another cooling pad from the store and it works fine. Connected for a few hours now without issue. It must be the power draw on the old cooling pad I’ve had.

I wasn’t aware that a device could draw too much power from a USB port – I thought the USB port itself would control the amount of draw allowed… I guess that’s incorrect?

It’s limited to a extent, with fans they can have reasonably high current draw. I cannot remember if the ports are 2.4 or 1 amp ports. Was it being suffocated as that can cause more current draw? The only exception to it being limited is if it’s directly connected between the plug and switch then the fans as there is no control circuitry. Does the old cooling pad have a current draw on the pad?

Unfortunately not… The port is usually just shut down by the USB controller if it exceeds the current limit. For USB2 that is 500mA, for USB3 it was 900mA (I have no idea what it is now).

Some desktop computers I’ve used don’t care about the limits, but laptops tend to be especially picky.

Depending on your drivers (if you’re on Windows) there used to be a pop-up notifying you that a port was shut down due to a power surge

I modified my Targus and am running two Noctua NF-A12x25 (5V version) off a single USB-A module continuously without any problem. The fans I removed from the Targus were lower spec’d.