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Post by Rick Flair on Nov 28, 2016 14:41:40 GMT -5
You said that the peak current is 1.2A to 1.3A, I’d like to know under what circumstances it will need that much current?
I’m currently using USB 2.0, which only has 0.5A, but the monitor works fine. I just want to make sure that the monitor will work fine under other circumstances.
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Post by Admin on Nov 28, 2016 14:42:54 GMT -5
It will draw 1.0-1.2A most of the time. Power will vary over brightness, so the higher the brightness, the higher the current. It is most certainly drawing more than 500 mA from his USB port right now.
The USB2.0 500mA limit is almost never enforced anymore. It is true that USB2.0 is supposed to only supply only 500 mA, which is why the Magic Touch models came with Y-cables to take power from multiple ports. However, USB2.0 spec is old, and there are newer products (displays, HDD, audio) that draw more power than that. Most every USB port now will happily supply more than 500 mA.
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Post by Rick Flair on Nov 29, 2016 12:26:18 GMT -5
Thanks for the quick response. In our design we have many USB devices on a HUB along with the MIMO monitor. The HUB is powered but I still have concerns about over loading it. We have 5 VDC output available on out PCB. Can we use that to supplement the USB 5DVC? Basically the same as the “Y” usb cable that was previously used but instead of going to another USB port going to a dedicated 5 VDC supply?
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Post by Admin on Nov 29, 2016 14:20:31 GMT -5
It would probably not work as a 'Y' connection. The issue is that you would be shorting 2 separate 5V power supply connections together. If they are not EXACTLY the same voltage then the stronger supply is going to win and the weaker supply will be giving 100% trying to control the voltage. If they want to use the PC 5V supply, my suggestion would be
1) a custom cable that ONLY takes power from the 5V signal. So long as the supplies are within spec then everything should work fine. The data and ground lines would come from the hub, and the power would come from the PC. I would suggest shorting the grounds together between the PC and the hub, which is probably already there between the cables
2) Use a hub that can handle the power needed. A USB 3.0 powered hub should work.
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