Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

Basic Electronics Questions. AMC7135

KRNAZNBOY

KRNAZNBOY

0
Joined
Mar 29, 2013
Messages
1,221
Points
63
I have designed a board in EAGLE. Does this look alright?

The pads on the left side are Bat+ and LD+ (bottom & top respectively)
Pads on the right are Bat- and LD- (bottom and top respectively)

BOARD_zps6151876b.png


Thanks in advance!
-Matt

^^^ Question above still stands. That design all right? It uses a 0.1uf cap (big rectangle) and the AMC7135 chip.

About the size of a MOH linear driver. Maybe a bit smaller.

The only reason i used a large cap is cause my soldering sucks.

Want to get these ordered so i can order the rest of the parts.

:beer:
-Matt
 
Last edited:





Bionic-Badger

Bionic-Badger

0
Joined
Oct 26, 2007
Messages
5,438
Points
83
crazyspaz said:
You realize they are 400mW PULSE diodes right?
CW is like 150mW for them
Click to expand...

Everyone here overdrives their diodes at the "pulse" ratings (or even above). Otherwise we'd be using some craptastic recommended figures, even if they lasted longer.

KRNAZNBOY said:
I have designed a board in EAGLE. Does this look alright?
Click to expand...

Dude, nobody wants to look at your PCB masks. Post the schematic.

You said you don't know how to read schematics? Learn to read schematics. Learn to write schematics. It's fundamental. In fact, you shouldn't be doing any board layouts until you've learned how to read, interpret, and write circuit schematics. Hell, even your board should be initially routed by your program from the schematic you design.

And why are you jumping to making a driver board first before testing the whole thing out on a breadboard? You don't even know if your circuit works! Don't ask us if your chip is within tolerances. You should be doing the experiments or gauging it from the datasheet (again, learn how to read schematics). Just because PCB manufacturing is cheaper these days doesn't mean you shouldn't be doing prototyping before you send your masks off to get fabbed.

Get some of those chips and wire them up to a breadboard. If you need heatsinking or can't wire it up properly, get a breakout board for your chip. If you want to know if you can power it with a single cell, do the experiment yourself on the prototype! Don't try to run when you can't even crawl.

Overall, some of your questions above qualify as "stupid questions". Why? Because you haven't done your homework first. If you don't know how to read a schematic, then you should learn that before asking basic schematic questions. If you haven't even prototyped your circuit, don't ask us to look at your PCB masks to check if they're correct. Come on dude. Get real. You shouldn't be expecting us to hand-hold you through basic electronics like this.

Don't make me break out the spoonfeeding picture again!
 
Last edited:
djQUAN

djQUAN

0
Joined
May 27, 2013
Messages
1,154
Points
63
If you rotate the chip 180degrees, you'll find that the lines will be much shorter and neater.
 
BShanahan14rulz

BShanahan14rulz

0
Joined
Dec 29, 2009
Messages
3,136
Points
63
With suitably short traces and diode leads, does the cap contribute anything worthwhile? I had made a crappy 1xAMC7135 + LOC build a while back, and it died after several months of torture (hooking it up to random batteries, living in a box full of metal parts, you know...)

I had the bare chip soldered between the leads, with a random insulated solid copper wire soldered to tab as a heatsink, and stuffed into an aixiz back-end. Never will know cause of death, but wondering if the capacitor would have helped in my case, or what even that capacitor is meant to do in general. Just about everything has a cap across inputs and outputs.
 
Last edited:
KRNAZNBOY

KRNAZNBOY

0
Joined
Mar 29, 2013
Messages
1,221
Points
63
BShanahan14rulz said:
With suitably short traces and diode leads, does the cap contribute anything worthwhile? I had made a crappy 1xAMC7135 + LOC build a while back, and it died after several months of torture (hooking it up to random batteries, living in a box full of metal parts, you know...)

I had the bare chip soldered between the leads, with a random insulated solid copper wire soldered to tab as a heatsink, and stuffed into an aixiz back-end. Never will know cause of death, but wondering if the capacitor would have helped in my case, or what even that capacitor is meant to do in general. Just about everything has a cap across inputs and outputs.
Click to expand...

I think they are meant to absorb starting current spikes/overshoots.

Right?

:beer:
-Matt
 
Gazoo

Gazoo

0
Joined
Jun 9, 2007
Messages
3,206
Points
38
KRNAZNBOY said:
NOOOO PLEASE :p

I will google it tonight.

But, does it look ok? Pretty please?

Bionic-Badger is right. A little homework goes a long way and there are tons of schematics and images ....Google it and learn. Your drawing is confusing. Good luck.
Click to expand...
 
Last edited:
KRNAZNBOY

KRNAZNBOY

0
Joined
Mar 29, 2013
Messages
1,221
Points
63
Gazoo said:
No. If I am looking correctly you have B- going to Out. Shouldn't it go to ground? Bionic-Badger is right. A little homework goes a long way and there are tons of schematics and images ....Google it and learn. Good luck.
Click to expand...

Ummmmmm. No. I hope you are not assuming that the left side is b- and right is b+

It is the opposite, and the only thing B- is going to is through the cap and to the GND tab of the chip....
 
Sigurthr

Sigurthr

0
Joined
Dec 11, 2011
Messages
4,364
Points
83
The cap prevents the chip from oscillating which can cause random diode death.


Sent from my iPhone using Tapatalk
 
Gazoo

Gazoo

0
Joined
Jun 9, 2007
Messages
3,206
Points
38
KRNAZNBOY said:
Ummmmmm. No. I hope you are not assuming that the left side is b- and right is b+

It is the opposite, and the only thing B- is going to is through the cap and to the GND tab of the chip....
Click to expand...

I edited my previous post. My bad but still when I started with the chip, and building lasers for that matter I knew nothing about them. I preferred to learn through trial and error. I gained much experience that way as well as reading this forum and using Google. Of course I asked questions if I got stumped. But I didn't want to be spoon fed. I know you can learn too if you take the time and have some patience.
 
KRNAZNBOY

KRNAZNBOY

0
Joined
Mar 29, 2013
Messages
1,221
Points
63
The only caps i found that are decent in price are here:

Invalid Request

Will these work. They are the right capacitance and size, but are rated for 250 volts :p

I don't know maybe the voltage rating affects how they work?

:beer:
-Matt
 
Sigurthr

Sigurthr

0
Joined
Dec 11, 2011
Messages
4,364
Points
83
Capacitor voltage rating doesn't affect performance, it simply needs to be larger than the worst case expected voltage seen at the node. Generally a safe margin multiplier is applied to determine the minimum rating suitable.
 
KRNAZNBOY

KRNAZNBOY

0
Joined
Mar 29, 2013
Messages
1,221
Points
63
Sigurthr said:
Capacitor voltage rating doesn't affect performance, it simply needs to be larger than the worst case expected voltage seen at the node. Generally a safe margin multiplier is applied to determine the minimum rating suitable.
Click to expand...

Schweet. I will hold off on ordering some PCBs until i test my design on a protoboard or something :)

Thanks guys
 
BShanahan14rulz

BShanahan14rulz

0
Joined
Dec 29, 2009
Messages
3,136
Points
63
Sigurthr said:
The cap prevents the chip from oscillating which can cause random diode death.


Sent from my iPhone using Tapatalk
Click to expand...


dag, sig, can't rep you, but that makes more sense. So it is the longer leads that could change how it senses the load might make the chip oscillations swing too far. Berry Interesting!
 
You must log in or register to reply here.




Top