Diode identification?

[DaveC]

From Japanese SMPS, looks like regular 1A rectifier diode. Labeled B320219
(the "02" is larger type than the others).

Can't find cross-reference. Any help would be greatly appreciated.

Thanks,

 

[Palindr☻me]

From Japanese SMPS, looks like regular 1A rectifier diode. Labeled B320219
(the "02" is larger type than the others).

Can't find cross-reference. Any help would be greatly appreciated.

Any chance of reverse-engineering the bit of the circuit it is used in,
and producing a bit of a circuit diagram?

 

[Pooh Bear]

Any chance of reverse-engineering the bit of the circuit it is used in,
and producing a bit of a circuit diagram?

It's probably not too tricky to acertain it's likely rating and speed by
judicious examination of where it lies in the gubbins.

Graham

 

[DaveC]

Thus spake Palindr☻me:

Any chance of reverse-engineering the bit of the circuit it is used in, and
producing a bit of a circuit diagram?

Not very good at this... just a component-test monkey (c:

But it (and its partner) seems to be across a c.t. winding of the SMPS
transformer. Electrolytic filter caps "downstream" from these are rated at
25v.

There are a dozen more of this type of diode in this SMPS, across other
trans. windings.

This is a multiple-voltage ps inside a 240v ac motor controller in a Japanese
printing press.

Thanks,

 

[Arfa Daily]

Thus spake Palindrâ~»me:


Not very good at this... just a component-test monkey (c:

But it (and its partner) seems to be across a c.t. winding of the SMPS
transformer. Electrolytic filter caps "downstream" from these are rated at
25v.

There are a dozen more of this type of diode in this SMPS, across other
trans. windings.

This is a multiple-voltage ps inside a 240v ac motor controller in a
Japanese
printing press.

Thanks,
--
DaveC
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If it's on the secondary side, it will not be a 'normal' 1A diode. It will
be a high speed Schottky type. If you try to use a standard silicon
rectifier diode, it will run very hot and fail, in short order.

Arfa

 

[ian field]

From Japanese SMPS, looks like regular 1A rectifier diode. Labeled B320219
(the "02" is larger type than the others).

Can't find cross-reference. Any help would be greatly appreciated.

Thanks,
--
DaveC
[email protected]
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Please reply in the news group

If testing it shows slight reverse leakage - it could be a Shottky-barrier
type, Most DMMs have a diode forward voltage test if the Vf is less than
about 0.4V and more than 0.1V it almost certainly is SB, if its glass
encapsulated - consider the possibility it's a zener, these show Vf about
0.7V, regular diodes show about 0.6V and fast silicon types usually
somewhere around 0.55V.

But if any of these tests pass - it's probably OK anyway!

 

[DaveC]

Thus spake ian field:

If testing it shows slight reverse leakage - it could be a Shottky-barrier
type, Most DMMs have a diode forward voltage test if the Vf is less than
about 0.4V and more than 0.1V it almost certainly is SB, if its glass
encapsulated - consider the possibility it's a zener, these show Vf about
0.7V, regular diodes show about 0.6V and fast silicon types usually somewhere

around 0.55V.

The other diode ("good" one) in the circuit measures 0.4v in DMM diode test
(Fluke meter). Not glass, epoxy (black stuff).

But if any of these tests pass - it's probably OK anyway!

Infinite both directions, according to diode test on the DMM.

Is SB type used as rectifier in SMPS? Or is vanilla Schottky used in this
application?

Thanks,

 

[ian field]

Thus spake ian field:



The other diode ("good" one) in the circuit measures 0.4v in DMM diode
test
(Fluke meter). Not glass, epoxy (black stuff).


Infinite both directions, according to diode test on the DMM.

Is SB type used as rectifier in SMPS? Or is vanilla Schottky used in this
application?

Thanks,
--
DaveC
[email protected]
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Please reply in the news group

Is "the other one" with 0.4Vf identical to the one you've taken out?

 

[DaveC]

Thus spake ian field:

Is "the other one" with 0.4Vf identical to the one you've taken out?

Yes, same markings. They're apparently a backward-connected set of rectifiers
across a SMPS ct transformer secondary.

Thanks,

 

[Pooh Bear]

Thus spake Palindr☻me:


Not very good at this... just a component-test monkey (c:

But it (and its partner) seems to be across a c.t. winding of the SMPS
transformer. Electrolytic filter caps "downstream" from these are rated at
25v.

You mean the anode ( or cathode ) of the diode is directly connected to a
reservoir cap ? It'll be a rectifier on the secondary side. It needs to be a high
speed type and from your mention of 25V, I'd probably use a 200V part ( for
safety's sake ). Current rating - you say it looks like 1A - would suggest a
UF4003 replacement. Are you sure about the current rating though ?
http://www.chipdocs.com/datasheets/datasheet-pdf/MCC/UF4001.html

Graham

 

[Pooh Bear]

If it's on the secondary side, it will not be a 'normal' 1A diode. It will
be a high speed Schottky type.

Not necessarily Shottky actually. ( btw - is it *meant* to have a 'c' in it or
not ? )

If you try to use a standard silicon
rectifier diode, it will run very hot and fail, in short order.

Oh I don't know. A subcontractor once fitted a 1N4004 where I'd specified a
UF4004 on a lightly loaded secondary. It ran for many hours before failing !

They did it second time round too ! I reckon that purchasing looked at the part
number and reckoned they could substitute. Lovely stuff working with Asians.

Funny thing was, my colleagues looked glum since it was our first smps design. I
( in my infinite wisdom ! ) smelt a rat and went to it almost straight off. It
was shorted. Just made the thing go into hiccup mode.

Graham

 

[DaveC]

Thus spake Pooh Bear:

http://www.chipdocs.com/datasheets/datasheet-pdf/MCC/UF4001.html

(That's a paid-subscription link...)

Re. the current rating, I'm just comparing the unit in question with a
non-schottky, vanilla 1A rectifier. They are similar in size.

Thanks,

 

[Pooh Bear]

Thus spake ian field:



The other diode ("good" one) in the circuit measures 0.4v in DMM diode test
(Fluke meter). Not glass, epoxy (black stuff).


Infinite both directions, according to diode test on the DMM.

Is SB type used as rectifier in SMPS? Or is vanilla Schottky used in this
application?

SB = Shottky barrier. Techy speak for 'shottky'.

Graham

 

[Pooh Bear]

Thus spake Pooh Bear:


(That's a paid-subscription link...)

Yabbut.... It gave a list of UF400x devices which I didn't find anywhere else
quickly. You can get the data easily with a bit of common sense. Oh sod it.....
http://www.fairchildsemi.com/pf/UF/UF4003.html get the pdf

Re. the current rating, I'm just comparing the unit in question with a
non-schottky, vanilla 1A rectifier. They are similar in size.

I ask for a reason. Do you know the current draw on the supply ? It pays to fit
a beefier device if unsure.

Graham

 

[Palindr☻me]

Thus spake Pooh Bear:




(That's a paid-subscription link...)

Re. the current rating, I'm just comparing the unit in question with a
non-schottky, vanilla 1A rectifier. They are similar in size.

The thickness of the wires coming out is often a better indication than
the size of the body.

IIUC, you aren't going into production with this thing, just trying to
get it working. So you can afford to err on the side of safety and put
in a well over-spec'ed schottky, even though a much lower spec'ed (i.e.
lot cheaper) device would be fine too.

Any idea why it failed?

 

[DaveC]

Thus spake Palindr☻me:

Any idea why it failed?

Nope. There are 4 identical controllers. They've all been purring along for
near 10 years without a hiccup.
--
Please, no "Go Google this" replies. I wouldn't
ask a question here if I hadn't done that already.

DaveC
[email protected]
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[DaveC]

Thus spake Pooh Bear:

SB = Shottky barrier. Techy speak for 'shottky'.

Not to get too bogged down in terminology, but
sb = schottky barrier = schottky ?

Thanks,

 

[DaveC]

Thus spake Pooh Bear:

I ask for a reason. Do you know the current draw on the supply ? It pays to
fit a beefier device if unsure.

Like this?:
http://www.nteinc.com/specs/500to599/pdf/nte580.pdf

I need it today and nte is the only maker available locally over-the-counter.


Thanks,

 

[Pooh Bear]

Thus spake Palindr☻me:


Nope. There are 4 identical controllers. They've all been purring along for
near 10 years without a hiccup.

Stuff gives up after a while sometimes !

Graham

 

[Pooh Bear]

Thus spake Pooh Bear:


Not to get too bogged down in terminology, but
sb = schottky barrier = schottky ?

Yes. The barrier bit is optional if you like. It's about the junction inside the
device. Like pn junctions. Except this one is a barrier. If one cares to be
verbose, ordinary silicon diodes could be called junction diodes.

Graham