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General => General Technical Chat => Topic started by: Memphis on July 15, 2013, 03:08:28 pm

Title: PnP supply protection [Guess the function of following scheme]
Post by: Memphis on July 15, 2013, 03:08:28 pm
So guess/examine/explain the usage of the following scheme  >:D:

Title: Re: Guess the function of following scheme
Post by: hlavac on July 15, 2013, 03:42:47 pm
Ummm, failed attempt at a synchronous rectifier? :)
Title: Re: Guess the function of following scheme
Post by: Memphis on July 15, 2013, 03:52:31 pm
Ummm, failed attempt at a synchronous rectifier? :)

Actually it works as it is :D ... it is not a synchronous rectifier but you are very close to the main function :)
Title: Re: Guess the function of following scheme
Post by: free_electron on July 15, 2013, 03:59:40 pm
lossless rectifier. the mosfets short their internal bulk diodes so you don't lose 1.2 volt per alternance.
Title: Re: Guess the function of following scheme
Post by: Memphis on July 15, 2013, 04:05:03 pm
lossless rectifier. the mosfets short their internal bulk diodes so you don't lose 1.2 volt per alternance.


True, it disallow reverse polarity, and it does one more, very important job.
Title: Re: Guess the function of following scheme
Post by: hlavac on July 15, 2013, 04:18:14 pm
True, it disallow reverse polarity, and it does one more, very important job.

So its protection circuit for DC power adapter input that protects from reverse polarity and overvoltage?
That could be said about the left side, what about the right side?

Title: Re: Guess the function of following scheme
Post by: Memphis on July 15, 2013, 04:32:34 pm
True, it disallow reverse polarity, and it does one more, very important job.

So its protection circuit for DC power adapter input that protects from reverse polarity and overvoltage?
That could be said about the left side, what about the right side?



The right part prevents current flowing when only positive polarity is connected to the left part and ground from right part is connected for example via signal cable to power supply. So it is some kind of Plug&Play supply. The "PnP bridge" will be opened only if both negative and positive polarity is connected on left side.  ;)
This is very useful when you have lazy technician which connects/disconnects everything under the powered source, it will save you signal/bus drivers.  :-BROKE
So it is much better than the simple diode and also a cheap solution.  :-+