Erdabyz's switching laser drivers

erdabyz said:

HIMNL9: I doubt a lot that your driver could only give 140mA to the load having a 1A switch. You did something wrong.
I did extensive testing with the LT1930 and i can assure you that this IC, having a 1A switch, can perfectly give around 650mA at 5.5V from a 4V source. Even more with LT1930A. It's REALLY important to make a well designed PCB for this drivers and to carefully pick the inductor and output capacitors. A fail in that will result in a fail in performance.

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Yes, is possible that you're right (also if was a led driver, not a laser driver) ..... as i've said, i have very small time for work on my projects, and no professional tools, so probably the pcb was not good (i know that about high frequency boost drivers, the pcb design is important, but i mainly do all my prototypes "hand made", so, nothing professional )

As example, when i made the prototypes for try the MAX8715, i ruined all the pcb for a stupid error (my guilty, too much hydrogen peroxide in the HCl), and i'm actually waiting for other thin coppered plates, so i'm stopped til they arrives.

Probably, making them done from a professional company can be better, but for tests and prototypes, it don't worth the effort and the needed money.

HIMNL9 said:

As example, when i made the prototypes for try the MAX8715, i ruined all the pcb for a stupid error (my guilty, too much hydrogen peroxide in the HCl), and i'm actually waiting for other thin coppered plates, so i'm stopped til they arrives.

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When making a PCB using insolation method there are some points in the process where epic fail is typical:

1º The printing in the transparency is not opaque enough.
Solution:
If using a laser printer, use maximum toner setting and use toner darkener spray.
If using an inkjet printer, print it with the highest photo quality available, and IMMEDIATELY after the printing is finished pour some talcum powder in the ink side and extend it properly. Then remove the leftovers with a soft tissue. That will both dry the ink and make it more opaque. That's the method I use and I can achieve almost professional resolutions.

2º There are air gaps between the transparency and the boad, so the contact is not perfect and some shadows appear. This may ruin thin tracks.
Solution:
The cheapest and most effective method available for holding the transparency against the boad with pressure is just sandwiching the board and the transparency between twho pieces of glass, and holding it with paper with this kind of clips:
http://www.exchange3d.com/cubecart/images/uploads/aff586/aa.jpg
Don't forget to put a small piece of board material where the clip clips the two pieces of glass, to avoid cracking it. This method also allows easy double-layer PCB's. You align both transparencies and glue them together making an envelope that will sandwich the double layer PCB

3º The PCB gets overdeveloped: lower the exposure time
4º When etching, the PCB gets more etched in the center than in the borders or the etching is irregular or excessive:
Use a slower etchant such as ferric chloride, and use it in small amounts. Instead of pouring half a litre of etchant in the tray and reuse it for a long period, just pour enough etchant to cover the PCB or even less, and keep rubbing the PCB with latex gloves during the etching process. Be careful not to breath the vapors. After the PCB is done just discard the etchant. It's way better to always start with fresh etchant than to reuse a big amount of etchant until it stops working. Same applies with the developer.

^ yes, this for photoresist ..... unfortunately, my bromograph died almost a year ago, and still had no time to build something better, so, the few pcb that i actually made, are all made with the "old, good system" ..... wax transfers, modelers painting, or adhesive plate cutted on the draw.

No good results, but better than nothing, at least til i find the time

Count me in for a few. I can't even afford anything more expensive than a PHR right now. So this is perfect. When will some be available?

They are not even designed yet... it will be a while before production
Driver would be ready... IMO
Correct me if I'm wrong...


Jerry

He's got pictures of them completed...so, it sounds like the design process is about done...

Bump, can't wait to see these available for sale.

Yeah, me too. They'll pwn.

Bearded_Galaxy said:

He's got pictures of them completed...so, it sounds like the design process is about done...

Click to expand...

The pictures are of the first design, which failed. He is now trying to make another one with different components but with the main design.