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I am building a linear power supply. I need a bridge rectifier and the diodes I currently have can only handle up to a maximum of 1 amp, but I need 4-5 amps.

But I have a bunch of YG862C15R Schottky barrier diodes.

Can I somehow use them as a bridge rectifier or have I got this all wrong?

Since it only has three pins, two for the AC IN and only one for the DC OUT (I guess), won't there be any negative? Like in an IC rectifier which uses four pins. How do these work?

Kevin Reid
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Xane
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4 Answers4

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In this application Schottky diodes will work just as well as normal diodes, by arranging them as you normally would a bridge rectifier. They are not normally used in regulators because they are more expensive and sometimes physically larger. The advantages of a Schottky diode (low forward voltage, fast switching) will not provide any benefit for an ordinary bridge rectifier.

The best option for hobby projects is to get a purpose made bridge rectifier that has all of your rectifier diodes integrated in one package. These cost about $2 in small quantities.

However, the specific part you have selected should not be used in a 120V bridge rectifier, because it will experience a peak-to-peak reverse voltage of 336V, well above the maximum rated 150V reverse voltage for this part. Don't do it.

And make sure you have a GFCI or isolation transformer between mains and your power supply.

jbarlow
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  • Thanks for the answer! Since i live in europe i have 230v mains, that goes to a 230 - 14v step down transformer and then i want to rectify that 14v. – Xane Mar 24 '16 at 07:35
  • Also what do you mean with GFCI or isolation transformer? Do you mean the green EARTH wire that is in the AC wire?Thanks. – Xane Mar 24 '16 at 07:41
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    120 V mains peaks at 168V, but peak-to-peak is 336V. And the diode, while holding off the reverse peak voltage on the negative part of the cycle, will see the load voltage in series with that, so 336V. And that's why it's called the "peak inverse voltage". – gbarry Mar 24 '16 at 07:48
  • I was just about to google the peak inverse voltage but you explained it very well, Thank you! – Xane Mar 24 '16 at 08:36
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    @Xane A GFCI is known as an RCD over here. Different laws mean slightly different behaviour, but basically it's a safety device which cuts off the mains supply if it detects current flowing out along the live but not back along the neutral. Handy if that current is flowing though you. If you're in the UK and your house is relativley new, there will be one built into your house wiring, otherwise you can buy plug-in ones from hardware stores. – Jack B Mar 24 '16 at 10:51
  • I see thank you! I live in Sweden tho. But i understand your point! – Xane Mar 24 '16 at 11:05
  • @gbarry thanks for pointing that out mistake. Fixed. – jbarlow Mar 25 '16 at 00:12
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Silicon Schottky diodes have a much lower voltage drop than the standard silicon types. You can't use them on mains, because they don't make them with high breakdown voltages. In fact, they are difficult to find above 200 V. There is a manufacturing tradeoff between breakdown voltage and forward voltage drop.

In your low-voltage application you could use say 40-volt Schottky diodes, and they would waste about half the power of a standard bridge rectifier. I have used three TO220 isolated packages on battery chargers in a previous life. On larger stuff I would use four TO220 packages and four TO247 packages for special occasions.

Nowadays I bypass them with MOSFETs, because they are available with low-enough on resistance to beat the Schottky diode when the output voltage is low.

Peter Mortensen
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Autistic
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Yes, you can use these for a bridge rectifier 'somehow', but you will need three packages.

You can use one package for the two diodes from AC to +ve, but you will need to use two separate packages for the two AC to -ve diodes. It doesn't matter much what you do with the spare diode in the -ve packages, leave it unconnected or parallel it with the other diode.

Neil_UK
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    I'm gonna try this now! Could you maybe draw some example? I think i understand how you meant but i just wanna be sure. Thanks! – Xane Mar 24 '16 at 07:38
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I am surprised that the only answer that fully answered the question got the least amount of points. Awful. The question asked about how to configure a 3-pin dual diode package to create a 4 pin bridge rectifier. Using 3 of them if you only have the one polarity is correct however if you can find a 3 pin package with the opposite polarity you could make a bridge with 2 of them - that is 1 common anode and 1 common cathode. Simply connect the 2 ac pins together on both packages and the common pins become the +ve and -ve pins from the bridge. It is much simpler than using 3 packages but you might need to buy one if you don't have both polarities. Or you could use one 3 pin package and 2 discrete shottky diodes of similar specs.

Michel Mainville
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    You may be unhappy with the votings of the users here. Nevertheless an answer is not the right place to articulate your unhappyness. Use the comments section for opinions. – Ariser Nov 06 '21 at 20:05