BLuRay mod #2. 1xAA boost circuit.

[IgorT]

Cool picture time.  Here's a shot of my Bluray's beam bouncing around inside my watch crystal.

That IS a very cool picture! Why is it bouncing around like that, and how come the beam is so thin?


BTW: I'll take some macros tomorrow. The camera i have here sucks at macros for some reason.. Otherwise it would seem these are a little more powerfull from the originals. My BR has a very high Vf after the premature death, and it was still getting 155mA @ 5.35V. The other model gives out 10mA less. And this is with a Ni-MH at 1.33V.

They might just be able to power a red through an AMC.. Quite impressive for such a tiny circuit.

 

[chimo]

It's below the critical angle .  <--------- Click the link.

I focused the Bluray to a narrow point.

[quote author=chimo link=1199303658/45#46 date=1205705780]Cool picture time.  Here's a shot of my Bluray's beam bouncing around inside my watch crystal.

That IS a very cool picture! Why is it bouncing around like that, and how come the beam is so thin?


BTW: I'll take some macros tomorrow. The camera i have here sucks at macros for some reason.. Otherwise it would seem these are a little more powerfull from the originals. My BR has a very high Vf after the premature death, and it was still getting 155mA @ 5.35V. The other model gives out 10mA less. And this is with a Ni-MH at 1.33V.

They might just be able to power a red through an AMC.. Quite impressive for such a tiny circuit.[/quote]

 

[IgorT]

Thanks! I'll look into it.

 

[IgorT]

I took some pictures of the Charge2Go clone PCBs..
The hard to read resistor is 1801.

It would be great, if this thing could supply 350mA at more than 3.3V, for the AMC to drive a red with a Ni-MH, and stay above 3.3V for a while, as the battery voltage drops.


Otherwise, i can use a 14500 Li-Po, throw the circuit out and only use the AMC... But this would kinda defeat the purpose.. They will definatelly work with blue rays, if i use a resistor close to the one you used.

 

[chimo]

This is definitely a much simpler circuit. It looks like a basic 5V boost controller.

Key components (top mark/code):
switcher chip - STVD
transistor - 2300
Schottky diode - SS14

Not many options to make any mods - the feedback goes right to the switcher chip so it's probably a fixed voltage.

I took some pictures of the Charge2Go clone PCBs..
The hard to read resistor is 1801.

It would be great, if this thing could supply 350mA at more than 3.3V, for the AMC to drive a red with a Ni-MH, and stay above 3.3V for a while, as the battery voltage drops.


Otherwise, i can use a 14500 Li-Po, throw the circuit out and only use the AMC... But this would kinda defeat the purpose.. They will definatelly work with blue rays, if i use a resistor close to the one you used.

 

[woop]

Re: BLuRay mod #2.  1xAA boost circuit.

that looks exactly the same as the one i have, and posted about ages ago in the ' Using a DC/DC converter to power the laser' thread

 

[IgorT]

that looks exactly the same as the one i have, and posted about ages ago in the ' Using a DC/DC converter to power the laser' thread

Did you get it out of a DX Charge2Go clone too?

I'll look into it.

EDIT: That was right at the beginning of the thread.. I see you bought it on e-bay.. Did it come from HK? It could have been someone drop shipping them from DX.

This is definitely a much simpler circuit.  It looks like a basic 5V boost controller.  
Not many options to make any mods - the feedback goes right to the switcher chip so it's probably a fixed voltage.

Thanks for the analysis.

If it was constant voltage, it should stay at that voltage up to a certain current, right? At low currents it would seem it is capable of keeping the voltage constant, so it should be good for a blue ray. Can't wait to get them!


I did some more testing, and it is definatelly going to be capable of powering an AMC, to get constant current for a while.. Next i need to check the lowest battery voltage, where it can still supply 350mA. So far it looks promising, and won't require any modification except for the AMC.. I'm gonna make at least one red using this, for variety.

 

[woop]

Re: BLuRay mod #2.  1xAA boost circuit.

ok whats this AMC you are all talking about?

 

[chimo]

[quote author=woop link=1199303658/45#53 date=1205789877]that looks exactly the same as the one i have, and posted about ages ago in the ' Using a DC/DC converter to power the laser' thread

Did you get it out of a DX Charge2Go clone too?

I'll look into it.

This is definitely a much simpler circuit.  It looks like a basic 5V boost controller.  
Not many options to make any mods - the feedback goes right to the switcher chip so it's probably a fixed voltage.

Thanks for the analysis.

If it was constant voltage, it should stay at that voltage up to a certain current, right? At low currents it would seem it is capable of keeping the voltage constant, so it should be good for a blue ray. Can't wait to get them!


I did some more testing, and it is definatelly going to be capable of powering an AMC, to get constant current for a while.. Next i need to check the lowest battery voltage, where it can still supply 350mA. So far it looks promising, and won't require any modification except for the AMC.. I'm gonna make at least one red with using this, for variety. [/quote]

Make sure you provide a power input reality check.

This may get a little complex. It depends on how it maintains regulation.

To put out 350mA at 5V (1.75 Watts) at an efficiency of say 70%, you would need to supply 2.5Watts. An alkaline will not last long at that power draw. A single NiMH would have to supply over 2 Amps to maintain that. Ouch!

 

[IgorT]

You are correct. I measured the current draw yesturday, and it was 2A, but the circuit was putting out >600mA at around 3.3V, if i remember correctly.. Besides, i never leave these on for long anyway.. I usualy don't go over 30 seconds.

I have one 16x red waiting for a host, and i really want to use this. I'm gonna keep the duty cycles even shorter than usual, so the battery can recover in the meanwhile. I also have to keep them short because of the diode itself, as it won't have much heatsinking other than the AixiZ module.


Besides, is there a better option when powering a red from a single AA cell? Matajumotors used a 5V boost circuit from DX and the AMC. And that circuit is supposed to have an even lower efficiency, so his current draw must be even higher.

 

[IgorT]

ok whats this AMC you are all talking about?

AMC7135 is a very LDO constant current regulator. It's not adjustable and can only put out 350mA. For a red, it works down to 3.3V, so it can be used with a single Li-Po cell.

You can get them from DX as flashlight drivers..  They come on small round boards, the same size as the charge2go boost circuits, and have a different number of AMCs on it, for different currents. You can buy one board with three for 4 or 5 dollars, or a larger number of boards, still held together in one large PCB sheet (cut out and perforated, so you just break them away). I ordered the one with 10 circuits with three AMCs each for $15.. They should be here towards the end of next week.


Gazoo wrote a thread about these, and tested them extensivelly. Many people here use them, and simply put a resistor in parallel with the load, to lower the current a little.


The only drawback is, that you can not ground the aixiz module, since the load minus is not at ground potential. Here's the datasheet: http://www.micro-bridge.com/data/ADD/AMC7135.pdf