USB ports VDD too low.

userHead jinlatt 2017-08-02 02:09:20 3119 Views1 Replies
Hi
Please check your 5V power supply for the USB ports.
From what I observed, (I am using a USB multimeter to monitor the Voltage level of the USB ports), the voltage level is at ~5V when there is no down stream devices connected.
However, when I connected a mobile device to it, the voltage drops to ~4.2V ish.
Moreover, I tried on both USB 2 and USB 3 ports, the current it can draw from both are similar, 0.46A, which is about right for USB 2, but for USB 3, the spec says it should support up to 0.9A of current. In other word, it does not meet the USB3 spec.

Please check and confirm.
thanks Attachments 51501610755_.jpg using USB 3 port 51501610755_.jpg (85.03 KiB) Viewed 2889 times 61501610759_.jpg using USB 2 port 61501610759_.jpg (91.79 KiB) Viewed 2889 times