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Fuses?

rhd

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Ok - in theory, could you:

1) Use an IR diode with bond wires that burn up at just under the COD current for your valuable diode.
2) Bridge solder across the emitter of your cheap IR, such that the pins effectively become continuous.

Premise being that without COD to deal with on your cheap IR, it basically IS just as fuse, not a diode. Assuming you could find a cheap IR diode with a bond-wire-death current that was the max you wanted to protect against, wouldn't this work? It would be a PITA and nowhere near worth the time, hassle, and complexity it would add - not to mention the fact that it isn't really necessary in the first place.... but wouldn't this work?

EDIT: Probably not. Because I'm betting the bond wires aren't "fast" to trip either.
 
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Well, the idea here was just to protect against mistakes, I guess. Say you have a driver driving a 12x 405, right? The driver is set to 450mA. However, the driver fails somehow, and starts pumping out 600mA. Now, most 405s could probably handle 600mA for a short period, but, if it was left on during this failure (maybe the user failed to notice), the diode could quickly die. I guess that was the basis for this thought experiment.
 

HIMNL9

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Still none think about the other possible problem ?

I mean, suppose you have a boost current drive that cannot work open-circuit, like the flexdrive ..... what happens when the fuse blow ? ..... open circuit, then "byebye flexdrive" too ..... the result ? ..... a diode AND a flexdrive to waste away, instead only the diode .....

EDIT: or also worse, the flexdrive die in shortcircuit, but you don't notice it, and thinking it was only the diode, you hook a second diode and turn it on again ..... the result ? ..... a flexdrive and TWO diodes to waste away .....
 
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Well, why would we need a fuse with an expensive and effective driver like the flexdrive? Those are proven to work. This was supposed to be with experimental drivers like LED ones from DX or whatever. And if the fuse blew and the driver blew, then the diode would live, would it not?
 

HIMNL9

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That, or just a 100nF + 1Kohm + 1N4148 (reversed) in parallel to the LD

Exagerating, also a 6V zenamic (just for be paranoid :p)


EDIT: just remembered that Zenamic don't make VDRs lower than 18V ..... other manufacturers do them, also SMD, anyway :p
 
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