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



Laser Pointer Store

Suutable driver for LPC-840

Mattronium

Active member
Joined
Dec 12, 2012
Messages
729
Points
43
I've used a amc7135 driver for my ML101U29 diode in my signature. As long as 350mA or 370mA is OK for you.
Just be careful as the amc7135 has a max input voltage of 5.5V IIRC so two Li-ion's will kill it.
 
Last edited:

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
14,600
Points
113
That's all any laser diode driver does. It regulates the current, not the voltage.
 

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
14,600
Points
113
Power supplies are called constant current and constant voltage controlled. Drivers are just drivers. They are supposed to be current controlled, but you often run up on Chinese drivers that are only voltage controlled. Caveat Emptor.
 

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
14,600
Points
113
Yes, there is a very good reason not to use this as your driver. They were made to drive LEDs and because LEDs are more forgiving of spikes and shifts in current they don't bother to filter them out. That is why these drivers are so cheap. I tried using them once many years ago and the failure of them kept me from ever making that mistake again.
 
Last edited:

hakzaw1

Well-known member
Joined
Apr 2, 2009
Messages
9,621
Points
113
are you wanting to sell it?,,
they cost about $2usd..
buy a laser driver..
 

KrombopulosRik

New member
Joined
Jul 29, 2018
Messages
12
Points
0
That's all any laser diode driver does. It regulates the current, not the voltage.

Not to challenge you here man but my studies of circuits and drivers says they control both? Or else you'd have bad voltages also flowing through the LD not just amps?
 

KrombopulosRik

New member
Joined
Jul 29, 2018
Messages
12
Points
0
Oh .So what about LM317?

LM is linear and regulates voltage via feedback loop, well too, but you MUST add a thermal runaway protection and amp/voltage limiting/breaker resistors/relays which ever way ya wanna go with it. The reason for this is the internal resistance of the LD varies under heat and the feedback loop will keep adding voltage and current to try to maintain that steady reference voltage. So no thermal protections = whats known as thermal run-a-away.
 
Last edited:

lasersbee

Well-known member
Joined
Sep 20, 2008
Messages
17,522
Points
113
Not to challenge you here man but my studies of circuits and drivers says they control both? Or else you'd have bad voltages also flowing through the LD not just amps?
LM is linear and regulates voltage via feedback loop, well too, but you MUST add a thermal runaway protection and amp/voltage limiting/breaker resistors/relays which ever way ya wanna go with it. The reason for this is the internal resistance of the LD varies under heat and the feedback loop will keep adding voltage and current to try to maintain that steady reference voltage. So no thermal protections = whats known as thermal run-a-away.
Double posting on the Forum in a short period
of time is frowned upon by the community...

It is easy to Combine and Edit your Posts by
using the [EDIT] button at the bottom right
of each of your Posts.


Jerry
 

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
14,600
Points
113
Not to challenge you here man but my studies of circuits and drivers says they control both? Or else you'd have bad voltages also flowing through the LD not just amps?
If you are talking about filtering out spikes and transients, that is only a side issue and not a control of voltage like one would see in a voltage regulator. If you are using a red diode you should know the the forward voltage is going to be low and therefore you wouldn't use a boost driver on that diode. If you are using a 490nm diode, you should know the forward voltage is quite high and you would want a boost driver. But, in the end, they are all just current regulators and nothing more. You can add a TTL input for PWM control of the output or and analog control that will vary the current between two set points, but it is still just a current regulator.
 

Cyparagon

Well-known member
Joined
Sep 12, 2007
Messages
9,601
Points
113
Not to challenge you here man but my studies of circuits and drivers says they control both?
"Not to challenge you, but here's a challenge"
Well, not to say you're wrong, but you're wrong.

You need only to look at a sample IV curve of a diode to see why:



Minor thermal effects aside, the diode can ONLY operate along this curve. For example, it is possible to apply 0.9V to a diode, and it is possible to send 5mA through a diode, but you CANNOT do both at once.
 




Top