foulmist
0
- Joined
- Mar 29, 2011
- Messages
- 1,056
- Points
- 48
Hello there...
I am new in this forum this is my first post actually! But I've read a lot of threads here... and I surfed the net for hundreds of hours looking for laser info...
I have even build 2 laser drivers out of scratch ... I even made my own PCBs with the FeCl3 method...
So there is one thing that I did notice...
Why is everybody building their drivers with LM317???
It has voltage drop of 3V ??? WAY TOO INEFFICIENT!!!!
Ok some will say it can be deliver 1.5A current... So what?
I've been in electronics since a kid and now i repair all kinds of Mobile Phones and other electronics for living...
When using lm317 you have to use power supply +3V of the actual laser diode voltage needed to operate.. why waste so much energy when using 2 x lithium batteries at full charge you get
8.4V minus
3V (lm317) minus
~3V (red LD) minus
~0.7 (silicon diode) optimal (there are other diodes with less voltage dropout for rectifying electricity .......
===============
u actually need over 6 volts and the other is dissipated as heat... not two mention the extra space needed for 2 BATTERIES
I have build my own 2 drivers using a low dropout voltage regulator (L1117) which has the same circuit build as LM317 but with voltage dropout of MAX 1.2V at 1A :wave: and i don't use such high dropout diodes for regulating the polarity (it's not even needed that much but i like to add them :na
L1117 (adjustable) can deliver 1A max current which is WAY OVER THE MAXIMUM for a RED LASER DIODE... so why don't you use this one for the red lasers and even for all others except for those who got 1W or over lasers....
AS ALTERNATIVE - !!! LM117 can even actually deliver 1.5A !!!!!! (SO WHY LM317)
ALSO there is a super efficient voltage regulator (a little hard to find where i live but it exists) with a voltage drop of 170mV!!!! at 1A current :drool:
TPS72501 (Adjustable) a little more work on this because it has a pin terminal that acts like a switch to enable input.
when I use these voltage regulators (as current regulators) I use only one 18650 Lithium Battery and i get FULL POWER without worrying how should I get a larger host for my laser for 2 or more batteries!!!
WOW!!! way more efficient than LM317 !!!
So I thought I should share my experience :na::beer:
any comments are appreciated
I am new in this forum this is my first post actually! But I've read a lot of threads here... and I surfed the net for hundreds of hours looking for laser info...
I have even build 2 laser drivers out of scratch ... I even made my own PCBs with the FeCl3 method...
So there is one thing that I did notice...
Why is everybody building their drivers with LM317???
It has voltage drop of 3V ??? WAY TOO INEFFICIENT!!!!
Ok some will say it can be deliver 1.5A current... So what?
I've been in electronics since a kid and now i repair all kinds of Mobile Phones and other electronics for living...
When using lm317 you have to use power supply +3V of the actual laser diode voltage needed to operate.. why waste so much energy when using 2 x lithium batteries at full charge you get
8.4V minus
3V (lm317) minus
~3V (red LD) minus
~0.7 (silicon diode) optimal (there are other diodes with less voltage dropout for rectifying electricity .......
===============
u actually need over 6 volts and the other is dissipated as heat... not two mention the extra space needed for 2 BATTERIES
I have build my own 2 drivers using a low dropout voltage regulator (L1117) which has the same circuit build as LM317 but with voltage dropout of MAX 1.2V at 1A :wave: and i don't use such high dropout diodes for regulating the polarity (it's not even needed that much but i like to add them :na
L1117 (adjustable) can deliver 1A max current which is WAY OVER THE MAXIMUM for a RED LASER DIODE... so why don't you use this one for the red lasers and even for all others except for those who got 1W or over lasers....
AS ALTERNATIVE - !!! LM117 can even actually deliver 1.5A !!!!!! (SO WHY LM317)
ALSO there is a super efficient voltage regulator (a little hard to find where i live but it exists) with a voltage drop of 170mV!!!! at 1A current :drool:
TPS72501 (Adjustable) a little more work on this because it has a pin terminal that acts like a switch to enable input.
when I use these voltage regulators (as current regulators) I use only one 18650 Lithium Battery and i get FULL POWER without worrying how should I get a larger host for my laser for 2 or more batteries!!!
WOW!!! way more efficient than LM317 !!!
So I thought I should share my experience :na::beer:
any comments are appreciated
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