EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: lhc on July 12, 2010, 08:00:47 pm
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I'm currently looking for some kind of USB galvanic isolation to protect my computer from too high voltages connected to USB ports. It has to be quick and support USB 2.0 at full speed (optocouplers are too slow for this, they only work good for RS-232 speed)
I have a ISP programmer with optoisolation but there are other devices that would need that kind of protection (i will be buying logic state analyser in the future and some other USB stuff).
There are few expensive isolators, maybe somebody has some nice schematics or links to some inexpensive devices?
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How about pulse isolation transformers?
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USB isolators are going to be expensive because of the high frequencies involved, it would probably require and USB transceiver on both sides of the transformer. If the USB is converted to something like UART or SPI inside the device, it's much easier to isolate that. I like the RF isolation devices like the AD iCoupler and similar devices from Silabs. There is a USB device in that line, but it's expensive and only does USB 2.0 full speed (which ironically is not at full speed).
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If you wait for a deal, you can get a wireless USB hub kit for about $20.
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You can have a look at http://www.circuitsathome.com/products-page/usb-interfaces . They sell a kit based on ADuM4160. The chip supports USB 2.0 full speed, not high speed.
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Try Silicon Lab's Si8410/20/21
Supports speed up to 150Mbps. Easy to use. The only trade of is that you need to provide power to it from each side.