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ArcticMyst Security by Avery

how to limit driver voltage

Joined
Jan 7, 2012
Messages
149
Points
18
I am looking at this diode on ebay.
In this case below, I assume the "Operating voltage" of this diode is the same as (V out) to the diode (Max 2.3V) from the driver.
So this is a one battery setup. 1x18650.

Some driver sellers today will set the current (I out to the diode) for the buyer but say nothing about setting the voltage (V out).
How do I find the correct driver for it?

Thank you for any help you can provide!


Brand: OpticsLD
Model No.: OPT808NM-1W
Center wavelength: 808nm
Output power: 1w
New/soldered: New
Can type: TO5-9mm
Operating current: Max 1.2A
Operating voltage: Max 2.3V
 
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WizardG

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Diodes are current driven devices. The driver is set for the desired current and it maintains that current regardless of the voltage to the diode. The voltage shown on the list of characteristics is just a typical voltage for running the maximum rated current through the diode.

As a diode warms up its forward voltage will drop. The driver will adjust its output voltage to whatever is required to keep the same amount of current flowing. That's the big reason you need to test boost drivers with a load. With no load they'll try and force current to flow by upping the voltage until they kill themselves.
 
Joined
Jan 7, 2012
Messages
149
Points
18
Hi WizardG - thank you for your answer!

1) So for the above diode, if I buy a single battery driver set to 1.2 Amps, I do not need to be concerned with the voltage since it should be within the spec of the diode?
2) I also assume the seller, when setting the current, has already connected the driver to a load to set the current in the first place?
3) I also assume the driver is a buck driver or buck/boost since a single battery will input 3 - 4 volts and the diode is stated to run at 2.3 volts when running at 1.2 amps?
4) Can you recommend some drivers or the best driver?
 
Last edited:

gazer101

Well-known member
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Feb 23, 2020
Messages
700
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Most of the time buck drivers will output slightly under what you put in (voltage wise). So if that diode calls for 2.3 volts, at most use 1 LiIon battery to power it. You should make a dummy load with the same Vf as the laser and hook it up to your driver to make sure the voltage and current check out before hooking it up to your actual laser
 
Joined
Sep 12, 2007
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Think of that particular specification as a passive value. The voltage of the diode will be - at most - 2.3V.

Just as a 1000Ω 1% resistor will be - at most - 1010Ω. You will not be able to alter this value, nor will you be able to alter the diode's maximum forward voltage. The exception of course is if you destroy them. Just as a resistor may begin to read ∞Ω if you overload it, a diode may also begin to behave with ∞Vf if overloaded.
 




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