Author Topic: Variable power supply output protection  (Read 829 times)

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Offline crystiTopic starter

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Variable power supply output protection
« on: May 22, 2022, 06:19:26 pm »
Hi guys!
What is the simplest output protection for reverse battery connection (blocking reverse input current) on 0-60V/5A variable power supply with two N-Channel transistors?

Example BJC polarity protector
  http://www.geofex.com/article_folders/cheapgoodprot.htm
Example single Mosfet protector
https://youtu.be/7Tk5ghH_U2s
Thanks in advance!
« Last Edit: May 22, 2022, 08:02:02 pm by crysti »
 

Offline jonpaul

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Re: Variable power supply output protection
« Reply #1 on: May 23, 2022, 08:02:55 pm »
séries and shunt diodes, eg Schottky,  inside feedback loop

j
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Offline David Hess

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Re: Variable power supply output protection
« Reply #2 on: May 24, 2022, 02:12:51 am »
séries and shunt diodes, eg Schottky,  inside feedback loop

That is how I do it.  At lower currents and voltage, a bipolar transistor can be used for lower voltage drop to do the same thing.

Some power supplies have a class-B or class-AB output so that they can also sink some current which helps keep the output voltage lower than the regulated voltage, but a series diode should still be used.
 

Offline jonpaul

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Re: Variable power supply output protection
« Reply #3 on: May 24, 2022, 05:31:18 am »
Dave, fine HP, Lambda lab variable power supplies have such protection diodes.

Faults occasionally blow up the diodes but the power supplies survived.

One other protection is an overvoltage crowbar, with an SCR and Zener at gate, in shunt with the output.

Jon
« Last Edit: May 24, 2022, 06:26:41 am by jonpaul »
Jean-Paul  the Internet Dinosaur
 

Offline crystiTopic starter

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Re: Variable power supply output protection
« Reply #4 on: May 25, 2022, 07:05:34 pm »
With diode protection power supplies not survives on reverse connection large capacity battery ex. >70Ah lead acid because sudden increase input current


Dave, fine HP, Lambda lab variable power supplies have such protection diodes.

Faults occasionally blow up the diodes but the power supplies survived.

One other protection is an overvoltage crowbar, with an SCR and Zener at gate, in shunt with the output.

Jon
 


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