Author Topic: USB Charger Reverse Connection Protection  (Read 74 times)

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Offline catalyst

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USB Charger Reverse Connection Protection
« on: Yesterday at 06:12:07 pm »
Hi,

I have designed a USB Charger for busses. We assume that a person may do a short circuit by using metal pen or tweezers etc. Because automotive a place that has very vandalism. I have to think anti-vandal solution for this. Because USB connectors are fragile to bad external factor. Do you have any suggestions for me? How can i protect USB connector by using a component or etc. For example, a diode may be acceptable but, diode's threshold voltage will decrease my USB voltage(5V) and this effect will affect my charge performance.

Thank you for answering.
 

Online Mr. Scram

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Re: USB Charger Reverse Connection Protection
« Reply #1 on: Yesterday at 06:23:56 pm »
Hi,

I have designed a USB Charger for busses. We assume that a person may do a short circuit by using metal pen or tweezers etc. Because automotive a place that has very vandalism. I have to think anti-vandal solution for this. Because USB connectors are fragile to bad external factor. Do you have any suggestions for me? How can i protect USB connector by using a component or etc. For example, a diode may be acceptable but, diode's threshold voltage will decrease my USB voltage(5V) and this effect will affect my charge performance.

Thank you for answering.
Maybe you could use a diode between the rails and have a 1K resistor on 5V and neutral to keep current from flowing that way under reverse conditions? Though if you want to do it nicely, it'd probably be a good idea to use a transistor. That way you'll barely have a voltage drop.

http://www.electroboom.com/?tag=reverse-polarity
 

Offline Jeroen3

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Re: USB Charger Reverse Connection Protection
« Reply #2 on: Yesterday at 07:15:42 pm »
One of those power switches from Micrel. (Microchip)
MIC2505 for example.
 


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