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



Laser Pointer Store

Drivers for 445

HIMNL9

New member
Joined
May 26, 2009
Messages
5,416
Likes
193
Points
0
Has anyone used a LD1085V from ST Micro as a basis for a DDL driver? Just curious because we are using it in a prototype board at work to drive a power hungry RF amp. I might have a spare or two to try it out.

Output: 1.25 to 28V @ 3A
Dropout voltage: 1.3V @ 3A

Datasheet
I think yes ..... i never tried it, cause here is difficult to find, and the price is too high, but, looking at the internal schematic (the part that i have marked, being precise), you can see that the differential configuration of the ADJ pin is not referred directly to any ground plane, only to the output line, that is basically the same configuration that is used for the LM317 series, so probably is possible to use it with the same type of circuit .....

Only, remember that, at these currents, you need to dimension the set resistor for them ..... like, around 3A, you will probably need a 5W ceramic resistor, for not kill it ..... ;) (and, for sure, no trimmers allowed :crackup:)
 

Attachments


BShanahan14rulz

Well-known member
Joined
Dec 29, 2009
Messages
3,175
Likes
151
Points
63
Can the flexdrive actually provide 1.5A at 5V on the output? Because the datasheet says no, but that doesn't mean that it can't.
 

BShanahan14rulz

Well-known member
Joined
Dec 29, 2009
Messages
3,175
Likes
151
Points
63
Looks like I'm sold on the flexdrive. Microboost has more neat features, but I don't really think I'd use 'em. I'd get too ambitious trying to hack a 3-mode LED "driver" to drive the TTL input or something crazy like that when I might could just use a switch and a resistor to have high and low(er) modes
 

HIMNL9

New member
Joined
May 26, 2009
Messages
5,416
Likes
193
Points
0
Can the flexdrive actually provide 1.5A at 5V on the output? Because the datasheet says no, but that doesn't mean that it can't.
Uhm, as far as i remember, is matter of total efficency, and this vary with the input voltage, output voltage, and load current ..... i'm not 100% sure, but i think that the safe working range for a flexdrive that feed a load of 5V, with an input voltage of 3,7V, may be around 600 / 700mA ..... over this, maybe it still work, but i don't bet about the stability, survival, or diode safety .....
 

boscoj

New member
Joined
Jun 12, 2010
Messages
451
Likes
25
Points
0
So what type of wires are you guys using for a full power flexdrive and a 445?

Will the wires from my i7 heatsink fan be large enough? Seems like the largest wire I can fit in there but motor rating is .30 A @ 12V . . .
 

midias

New member
Joined
Mar 14, 2010
Messages
639
Likes
26
Points
0
So what type of wires are you guys using for a full power flexdrive and a 445?

Will the wires from my i7 heatsink fan be large enough? Seems like the largest wire I can fit in there but motor rating is .30 A @ 12V . . .
you are running a low duty cycle so you should be ok.


American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies Should be accurate for non mil spec




I think I used 22awg mil spec wire it was the biggest I could fit and it was rated for over an amp
 

boscoj

New member
Joined
Jun 12, 2010
Messages
451
Likes
25
Points
0
finally found my magnifying glass and it says AWG 26 . . .

found some 20 ga . . . that would probably be better . . .
 
Last edited:

boscoj

New member
Joined
Jun 12, 2010
Messages
451
Likes
25
Points
0

BShanahan14rulz

Well-known member
Joined
Dec 29, 2009
Messages
3,175
Likes
151
Points
63
Most modes are achieved using PWM. If using a simple linear reg with a set resistor, just use two different resistors.
 

boscoj

New member
Joined
Jun 12, 2010
Messages
451
Likes
25
Points
0
most modes for these Cree lights? hmm that wouldn't work I'm guessing?

should be an easy hack to disable I'm thinking???

Most modes are achieved using PWM. If using a simple linear reg with a set resistor, just use two different resistors.
 

plexus

New member
Joined
Dec 9, 2007
Messages
442
Likes
47
Points
0
most modes for these Cree lights? hmm that wouldn't work I'm guessing?

should be an easy hack to disable I'm thinking???
most <100% modes for LED flashlights use PWM. but thats handled with the driver in them. you might be able to use those as hosts for LD. maybe.
 

Fivos

New member
Joined
Sep 6, 2010
Messages
54
Likes
1
Points
0
Hey guys. I am new in laserpointerforums and I am building a 445nm laser. Can you please tell me if I can use a jayrob flashlights build in driver (I think its about 900ma) to power my laser diode without a flexdrive or microboost driver???
 

3zuli

New member
Joined
May 30, 2009
Messages
811
Likes
32
Points
0
what kit are you using? as long as the stock driver isn't boost driver or the host uses just 1 lithium battery it won't be able to deliver enough current into LD (LD needs >5V, but battery is only 3.7)
 
Last edited:

jib77

New member
Joined
Jun 19, 2010
Messages
718
Likes
69
Points
0
The drivers in Jayrob kits are flexdrive or microboost, which ever you want. Although the flexdrive may be out of stock for now. Lucky for you both can be used for 445.

If you are talking about the LED driver that comes with the host, they are usually not well protected against current spikes and can kill your diode.

Hey guys. I am new in laserpointerforums and I am building a 445nm laser. Can you please tell me if I can use a jayrob flashlights build in driver (I think its about 900ma) to power my laser diode without a flexdrive or microboost driver???
 
Last edited:




Top