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The XBOX 360 HD-DVD high power laser thread

So some of the HD DVD diodes are more powerful then the ps3 diodes? :-?
I am thinking that some of the "broken" HD DVD drives
are the ones with the freak diodes in them. ::)

--hydro 8-)
 





Both of the diodes in the XBOX drives are more powerful than the PS3 diode.. The 811 diode can be pushed to 60mW, and the 803T diode cn be pushed to over 100mW ;D

This thread is a LONG read, but worth it for all the info.. along with the IP thread for the 811 diode..
 
clajef said:
One more dumb question - and if it's in the instructions with the lavadrive, just ignore me. The dummy load of 5 1N4007 silicon diodes: is that wired series or parallel? I'll start looking through the forums to see if I can dredge this up myself... Thanks again
Click to expand...

I don't know what exactly is in the LavaDrive instructions.. I do know it says that you shouldn't power the driver up without a load, because i am using a very similar driver, and i know this kills them, so i asked Dr_Lava if his is the same, and he said it's in the instructions..

The dummy load should be diodes wired in series. In parallel, they won't do you much good. Each diode has a certain forward voltage (Vf), and if you wire them in series, this voltage drop increases.

In any case, you NEED to get a higher Vf than 2.4V or the LavaDrive won't work properly and you won't be able to set the current. That is why i told you to measure the voltage on the circuit output, to verify it is above 2.4V, just in case..

And using the 1 Ohm resistor i mentioned is much safer than putting a DMM between the driver and the diode. And in the end you can just leave it in.


BTW, since these questions are much more related to the driver side of a laser build, you should be asking them in Dr_Lava's thread..
 
I'm going to modify a mini driver from 38ma to 88ma.(just ad a 25ohm resistor)
 
Are you using a rkcstr driver?

How low can the batteries discharge, before it drops out of regulation?
 
The regulator works until battery voltage drops below 2.5v OVER what the diode draws. A bluray diode draws~5v, so minimum supply voltage on a rkcstr driver is 7.5v.
 
You mean resistor? A pot might not be able to handle the current...

The theoretical dropout voltage is 2.25V, and a diode needs ~5.15V for 90mA. So the driver should remain in regulation down to 7.4V...

This means the current will stay constant down to 3.7V per battery. When they are full, they have 4.2V, so it would work for a while, before the current would start dropping.
 
Glaserfan said:
The regulator works until battery voltage drops below 2.5v OVER what the diode draws. A bluray diode draws~5v, so minimum supply voltage on a rkcstr driver is 7.5v.
Click to expand...

Isn't it 2.25V for his driver?

Anyway, there are tiny variances in each component, so some might be able to go lower than that. The specified dropout voltage is just what is guaranteed by the manfacturer..



This configuration doesn't make full use of the battery capacity, but it would work for a while, and since we're all using rechargables anyway, it really doesn't matter.
 
Correct.. I wat just going for the "safe" range 8-). I see no sense in risking diodes just to get the last few drops out of a battery:)
 
IgorT said:
[quote author=Glaserfan link=1209940381/408#408 date=1211651581]The regulator works until battery voltage drops below 2.5v OVER what the diode draws. A bluray diode draws~5v, so minimum supply voltage on a rkcstr driver is 7.5v.
Click to expand...

Isn't it 2.25V for his driver?

Anyway, there are tiny variances in each component, so some might be able to go lower than that. The specified dropout voltage is just what is guaranteed by the manfacturer..



This configuration doesn't make full use of the battery capacity, but it would work for a while, and since we're all using rechargables anyway, it really doesn't matter.[/quote]

Yeah if it works in regulation down to 3.7volts per cell, thats perfect. Past 3.7 volts, lithium cells drop in out put extremely fast, thats why i prefer lithiums over alkaline because the graph curve of lithium puts out almost full power until its drained, Then it just suddenly drops.

edit: oh and the dx trustfire cr123 seem to have a nominal voltage of 3.8volts not 3.6 because thats where mine settle too for hours.
 
Glaserfan said:
Correct.. I wat just going for the "safe" range 8-). I see no sense in risking diodes just to get the last few drops out of a battery:)
Click to expand...

You would not be risking a diode if you let it run below the minimum voltage for regulation..

The current starts dropping, not raising. :) The only way you can kill a diode is if you adjust the current when the driver is below the minimum voltage required for regulation. Then, when there is enough current again, the driver will put out what you actually set it to, and kill the diode.

But since there is no pot here, and only a resistor setting current, this can not happen. The only thing that would happen is, that you would notice the power dropping,
 
Lets see... (1) Thanks again, IgorT - great information. I am certainly going to take all of your advice including the 1 ohm resistor trick. (2) I spotted the warnings about no load conditions in some other posts - seems DrLava's trogulating framistator has the same issue that your driver circuit does... I might have that component name wrong. (3) OK, dummy load Vf must be>=2.4V or we might not be setting current correctly and endangering our LD when we connect it later. I assume we are also at some point endangering the driver itself if the Vf is low enough. And Finally, (4) Sorry for the forum faux pax. I will stop speaking driverese here in this thread. Thanks again.

JeffP
 
Trogulating framistator?!? ;D

I've never heard of that. :D It's usually called a regulator or a driver IC. And the no load issue is not really an issue, it's just the way current sources work. A current source always tries to give the load as much voltage as needed for the desired current to flow through it.

A linear regulator, like the 317 will also behave the same way. With no load it will try to increase the voltage to reach the current that is set, but it can't, so it maxes out at slightly below the supply voltage.

But since LavaDrive is a buck/boost driver, it can make a voltage lower or higher than the source. And with no load, it will do the same thing - try to increase the voltage, to make the desired current flow through the load. But since the load is air, it will just keep trying to increase the output voltage untill it fries itself.

This issue can be solved by soldering a Zener diode of a high enough breakdown voltage (higher than the Vf of the laser diode) across the output in reverse. As the driver would increase the voltage, it would reach the zener voltage, and the current would flow through that diode, and the circuit would be saved. This would cost some PCB real estate, and the driver would be bigger, but in most hosts it should even be possible to use a regular through hole zener.. You can ask Dr_Lava how to do this if you're worried, but if you have your LD permanently soldered, everything will be just fine.

When the Vf is too low, this doesn't endanger the driver itself. It is just, that it will dump all the current it can through the load instead of the current you set. With a diode this can't happen, as it's voltage drop won't change unless it's dead already. The only way this could be a problem would be if you were setting the current in this state. Once the driver would again have the proper load, the current would not be what you thought you set it to. It would be lower i think, or maybe you couldn't change it under those conditions anyway..


If you follow the instructions i already gave you, and are careful with the diode, everything will be ok.


Anyway, good luck on your build! Looks like you're all set. Make sure you post some pics when you're done.
 
clajef: You really made my day with the "trogulating framistator" ;D

I can't stop laughing! :) The name is so incredibly funny.. :D


Can i name my lasers after it? ;)
 
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