Laser pointer discussion. Read/write reviews of laser pointers and laser pointer companies. Learn about all types of laser pointers and lasers





Welcome to Laser Pointer Forums! If you are looking for a laser pointer or want to compare different laser pointer companies, you may want to check out the LPF Laser Pointer Company Database. The link will open in a new window for your convenience.








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes
Laser Technology Laser Pointer Parts Lasers by Wavelength
Top 10 Laser Pointer Companies Laser Pointer Company Database Visible Beam Laser Pointers


One laser store meets all your needs

























Go Back   Laser Pointer Forums - Discuss Laser Pointers > Lasers > Tutorials, Help & Repairs



LPF List of Laser Pointer Companies (link opens new window)



Reply
 
LinkBack Thread Tools Display Modes
Old 12-22-2009, 09:43 AM #1
Class 1M Laser
 
Join Date: Sep 2008
Posts: 230
Rep Power: 9
LiveRock is on a distinguished road
LiveRock LiveRock is offline
Class 1M Laser
 
Join Date: Sep 2008
Posts: 230
Rep Power: 9
LiveRock is on a distinguished road
Default Building a low voltage, high power constant current laser diode driver

Hi

I need to build a constant current laser diode driver.
I have all the logic circuit designed to monitor temperature, TEC cooling control and turn off/on the laser diode power input but I am still lacking a high power constant current driver.

In another post (WTB: laser Power Supply), I mentioned I will be using a TI PTH08T250W unit.
I will feed it 12 V from a PC power supply.
It will regulate the output to about 2.2V; which is the estmated lasing voltage for the laser diode.

However, I need to regulate the current as well to about 40-49 amps.

Does anyone has a circuit (MOSFET, etc.) to do that at about 1.5V to 2.5V?

Thanks!


LiveRock is offline   Reply With Quote







LPF List of Laser Pointer Companies (link opens new window)







Old 12-22-2009, 10:10 AM #2
HIMNL9's Avatar
Class 4 Laser
 
Join Date: May 2009
Location: Lost somewhere in the EU mess ;)
Posts: 5,416
Rep Power: 404
HIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond repute
HIMNL9 HIMNL9 is offline
Class 4 Laser
HIMNL9's Avatar
 
Join Date: May 2009
Location: Lost somewhere in the EU mess ;)
Posts: 5,416
Rep Power: 404
HIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond repute
Default Re: Building a low voltage, high power constant current laser diode driver

Wait, you can OR build a constant voltage regulator, OR build a constant current regulator, not both together (cause constant current regulators keep the current stable changing the voltage, ofcourse)

You can use the same schematic that i use for make my constant current sources (attached the principle schematic), but you have to change the sense resistor and, ofcourse, parallel enough mosfets for hold the current that you need (and not knowing what mosfets you have, i cannot say you the related values, sorry)
Attached Thumbnails
Building a low voltage, high power constant current laser diode driver-highcurrent-reg.jpg  
__________________
High Impulse Multipath Neutron Laser (mark 9 ) (LOL)
Dare mo mita koto no nai, kaze, kumo, suna, umi ..... Kokoro no hate no doko ka eien ga kagayaku.
HIMNL9 is offline   Reply With Quote
Old 12-23-2009, 12:29 PM #3
HIMNL9's Avatar
Class 4 Laser
 
Join Date: May 2009
Location: Lost somewhere in the EU mess ;)
Posts: 5,416
Rep Power: 404
HIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond repute
HIMNL9 HIMNL9 is offline
Class 4 Laser
HIMNL9's Avatar
 
Join Date: May 2009
Location: Lost somewhere in the EU mess ;)
Posts: 5,416
Rep Power: 404
HIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond repute
Default Re: Building a low voltage, high power constant current laser diode driver

IRFP054 is a good choice for high currents, it can easily keep 60A (64 max) continuous in ON state with a maximum voltage of 60V and can dissipate til 230W max ..... but for use it as current source in a current stabilizer, if you plan to build a variable or "modulable" system, i suggest you to use at least 2 of them, with a good heatsink (not that just one can't hold it, but i'm a maniac of safety ..... paralleling 2 of them, you divide the power dissipation that each one have to dissipate, and double the safety level of the circuit) ..... the only possible problem is that they require too much current for the gate, so you need to use a second op-amp as buffer, but this is the least problem.

Anyway, also with just one of them, coupled with a good heatsink, just for precaution, you must be safe, if you need a decent output current regulator ..... it have a decently low RDSon, so also the dissipation is relatively low ..... just optimize the input voltage of the circuit for keep the dissipated energy as low as possible, (say, 3V, max 3,5V) without compromise the function of the regulation, and you're OK (but with this current value you probably have to lower the resistance that is connected from the potentiometer and ground ..... all these values depend from the final current that you want ..... as example, i suggest you to change that part of the circuit in this way: in place of the 1 K resistor, a 4.7 Kohm trimmer, and in place of the 1 K potentiometer, a 3.3Kohm one, and considering that this circuit was designed for lower mosfets, change the 47K resistor between the positive and the gate with a 10Kohm one .....

Depending from your setup, may also be necessary to use a 0.05 ohm or less resistor as sense resistor, instead 0.1 ohm ..... with these low values, is usually better to use constantane wire resistors, or constantane plate ones, and can be put more than one in parallel, if you don't find the needed values ..... it's practically impossible to measure them with normal multimeters, you need a milliohmeter, or just buy them already made for the needed values ..... also, considerate that also this resistor hold the same current that you have at the output, so you need to dimension it for the right power ..... just as example, if you use a 0.01 ohm one, with 50 A you have 0.5V on it, that means 25W of dissipation ..... so, at least 40 or 50W resistor is needed for not "cook" it .....

Then, you can set a maximum current that is under the limit of the mosfet, during the setup ..... turning both the trimmer and the potentiometer for the minimum current, with an amperometer in serie to the load, powering up the unit, turning the potentiometer for the maximum current (keeping an eye on the amperometer ), then turning the trimmer until you reach the maximum value that you want, paying attention to never go over 55A or similar ..... in this way, the current remain regulable in a certain range, but never go over the limit set with the trimmer.

Ofcourse, i suggest you to do these tests using a dummy load that can hold these currents and dissipate these powers ..... the better choice can be a LEDed diode bar similar to the good one, still working as diode and eating power, but already damaged as laser, so it's the more similar to the real one ..... in alternative, a low value BIG resistor, like, 0.1 ohm 200W wire resistor, can be ok

BTW, if you find a precision 0.01 ohm resistor, you can easily use it also for measure the current, just placing a millivoltmeter in parallel with the resistor ..... at 200mv scale, the usual scale of these meters, each mV is 1A, and cause they are 3 1/2 cyphers, you have an instrument that measure til 199A with 100mA steps

And, just as suggestion, if you don't find the right type of shunt resistor in any electronic shops (is not easy, i know it for personal experience), there's an alternative on ebay, that is a bit uncommon, but that can work good ..... there's for sale a lot of relatively cheap lcd or led meters, that are proposed already set for certain ranges, like, 200VAC, 20VDC, 200ADC , and so on ..... the 200A DC ones, are sold with a shunt resistor that is already the right value and power that you probably need .....
__________________
High Impulse Multipath Neutron Laser (mark 9 ) (LOL)
Dare mo mita koto no nai, kaze, kumo, suna, umi ..... Kokoro no hate no doko ka eien ga kagayaku.
HIMNL9 is offline   Reply With Quote
Old 12-23-2009, 12:35 PM #4
HIMNL9's Avatar
Class 4 Laser
 
Join Date: May 2009
Location: Lost somewhere in the EU mess ;)
Posts: 5,416
Rep Power: 404
HIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond repute
HIMNL9 HIMNL9 is offline
Class 4 Laser
HIMNL9's Avatar
 
Join Date: May 2009
Location: Lost somewhere in the EU mess ;)
Posts: 5,416
Rep Power: 404
HIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond repute
Default Re: Building a low voltage, high power constant current laser diode driver

Uh ..... why my posts are gone before your one ? ..... i posted after you ..... your post hour shifted from AM to PM ..... maybe Avery is upgrading something in the forum DB .....

EDIT: heard about this from c0ld, and he said that it's due to a MB change and clock problems ..... it's normal, and will cause some troubles with post orders for the next few hours (probably 3 or 4, if the time that i see is right.

Posted this as advice, as c0ld asked, for the others that may have or notice the same thing.
__________________
High Impulse Multipath Neutron Laser (mark 9 ) (LOL)
Dare mo mita koto no nai, kaze, kumo, suna, umi ..... Kokoro no hate no doko ka eien ga kagayaku.

Last edited by HIMNL9; 12-23-2009 at 01:46 PM.
HIMNL9 is offline   Reply With Quote
Old 12-23-2009, 04:52 PM #5
Class 1M Laser
 
Join Date: Sep 2008
Posts: 230
Rep Power: 9
LiveRock is on a distinguished road
LiveRock LiveRock is offline
Class 1M Laser
 
Join Date: Sep 2008
Posts: 230
Rep Power: 9
LiveRock is on a distinguished road
Default Re: Building a low voltage, high power constant current laser diode driver

Thanks, HIMNL9.

I have no idea what MOSFET to get. With your experience, would you recommend something to do 40 to 49 amps?
LiveRock is offline   Reply With Quote
Old 12-23-2009, 09:12 PM #6
billg519's Avatar
Class 3R Laser
 
Join Date: Feb 2008
Location: London, Ontario, CANADA
Posts: 1,056
Rep Power: 129
billg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond repute
billg519 billg519 is offline
Class 3R Laser
billg519's Avatar
 
Join Date: Feb 2008
Location: London, Ontario, CANADA
Posts: 1,056
Rep Power: 129
billg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond reputebillg519 has a reputation beyond repute
Default Re: Building a low voltage, high power constant current laser diode driver

Also with MOSFETs, you must be concerned with the Vgs, or voltage required to turn on the gate. Some MOSFETs need 20V to be fully "on". A logic level MOSFET will have a more reasonable gate voltage requirement. There are logic level MOSFETs that can handle a lot of current, and 5V to the gate will have it fully turned on.

EDIT : Nearly forget ... you also need the lowest possible Rds ON value for your MOSFET.
__________________
I have a few lasers ... (62 handhelds, 11 labbies, 7 gas lasers, and 6 LPM's) I need more ... I have lots of goggles too! Eye safety comes first!

Last edited by billg519; 12-23-2009 at 09:18 PM.
billg519 is offline   Reply With Quote
Old 12-24-2009, 03:31 AM #7
Class 1M Laser
 
Join Date: Sep 2008
Posts: 230
Rep Power: 9
LiveRock is on a distinguished road
LiveRock LiveRock is offline
Class 1M Laser
 
Join Date: Sep 2008
Posts: 230
Rep Power: 9
LiveRock is on a distinguished road
Default Re: Building a low voltage, high power constant current laser diode driver

Thanks for all that information!!

I think I have a problem..
I an using a TI PTH08T250W to regulate the voltage from a PC power supply 12V to around 2.2V output...

With 2.2V, I can't even turn on the MOSFET whether logic level or not....
this is getting tough... HELP!!
LiveRock is offline   Reply With Quote
Old 12-24-2009, 03:41 AM #8
Hemlock_Mike's Avatar
Class 4 Laser
 
Join Date: Jan 2007
Location: North Iowa
Posts: 6,184
Rep Power: 3654
Hemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond repute
Hemlock_Mike Hemlock_Mike is online now
Class 4 Laser
Hemlock_Mike's Avatar
 
Join Date: Jan 2007
Location: North Iowa
Posts: 6,184
Rep Power: 3654
Hemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond repute
Default Re: Building a low voltage, high power constant current laser diode driver

I believe there is a circuit which feeds the sence input of the PTH08 module to make it CC. It may be on the data sheet for the device. It uses an external OP amp and a sence resistor. It can be done.
I plan to run mine with manual voltage control metering V & A. I don't need full power yet. I'm just trying to get the beam under control.

HMike.
__________________
It's a dog's life
Hemlock_Mike is online now   Reply With Quote
Old 12-24-2009, 05:53 AM #9
Class 1M Laser
 
Join Date: Sep 2008
Posts: 230
Rep Power: 9
LiveRock is on a distinguished road
LiveRock LiveRock is offline
Class 1M Laser
 
Join Date: Sep 2008
Posts: 230
Rep Power: 9
LiveRock is on a distinguished road
Default Re: Building a low voltage, high power constant current laser diode driver

Hi Mike

I read thru the data sheet. There is no mention about Current Control using an external OP amp....

There are stuffs like external resistor to fix output voltage, calculation of input and output capacitors, TurboTrans feature, inhibit pin, low voltage lock .... etc .... but no mention of current except that if there is a over current, the unit will shut down and attempt to resume function....

Where can I find this CC information? Thanks!
LiveRock is offline   Reply With Quote
Old 12-24-2009, 08:53 AM #10
HIMNL9's Avatar
Class 4 Laser
 
Join Date: May 2009
Location: Lost somewhere in the EU mess ;)
Posts: 5,416
Rep Power: 404
HIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond repute
HIMNL9 HIMNL9 is offline
Class 4 Laser
HIMNL9's Avatar
 
Join Date: May 2009
Location: Lost somewhere in the EU mess ;)
Posts: 5,416
Rep Power: 404
HIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond reputeHIMNL9 has a reputation beyond repute
Talking Re: Building a low voltage, high power constant current laser diode driver

^ scroll up, i posted yesterday, but cause the server clock problem, the posts gone before your one (just in case you have not see it )
__________________
High Impulse Multipath Neutron Laser (mark 9 ) (LOL)
Dare mo mita koto no nai, kaze, kumo, suna, umi ..... Kokoro no hate no doko ka eien ga kagayaku.
HIMNL9 is offline   Reply With Quote
Old 12-26-2009, 03:30 AM #11
Class 1M Laser
 
Join Date: Sep 2008
Posts: 230
Rep Power: 9
LiveRock is on a distinguished road
LiveRock LiveRock is offline
Class 1M Laser
 
Join Date: Sep 2008
Posts: 230
Rep Power: 9
LiveRock is on a distinguished road
Default Re: Building a low voltage, high power constant current laser diode driver

Hi Mike

I think the sense pin you mentioned is the voltage sense; there are 2 sense + and sense -.

There is no current control for this module; looks like I just blew another $79
LiveRock is offline   Reply With Quote
Old 12-30-2009, 06:08 AM #12
Class 1M Laser
 
Join Date: Sep 2008
Posts: 230
Rep Power: 9
LiveRock is on a distinguished road
LiveRock LiveRock is offline
Class 1M Laser
 
Join Date: Sep 2008
Posts: 230
Rep Power: 9
LiveRock is on a distinguished road
Default Re: Building a low voltage, high power constant current laser diode driver

anyone?
LiveRock is offline   Reply With Quote
Old 12-30-2009, 07:40 AM #13
jaycey's Avatar
Class 2 Laser
 
Join Date: Apr 2009
Location: London
Posts: 482
Rep Power: 24
jaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud of
jaycey jaycey is offline
Class 2 Laser
jaycey's Avatar
 
Join Date: Apr 2009
Location: London
Posts: 482
Rep Power: 24
jaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud ofjaycey has much to be proud of
Default Re: Building a low voltage, high power constant current laser diode driver

Is this of any use?

http://www.die4laser.com/D4Chill/D4Chill.jpg
http://www.die4laser.com/D4Chill/D4Chill.txt
http://www.die4laser.com/D4Chill/D4Chill_Sch.pdf
jaycey is offline   Reply With Quote
Old 01-17-2013, 03:59 AM #14
Junior Member
 
Join Date: Jan 2013
Posts: 1
Rep Power: 0
baothanh123 is on a distinguished road
baothanh123 baothanh123 is offline
Junior Member
 
Join Date: Jan 2013
Posts: 1
Rep Power: 0
baothanh123 is on a distinguished road
Default Re: Building a low voltage, high power constant current laser diode driver

Quote:
Originally Posted by HIMNL9 View Post
^ scroll up, i posted yesterday, but cause the server clock problem, the posts gone before your one (just in case you have not see it )
Hi HIMNL9, I am Thuong, i come from Vietnam. Now i have a project about constant current use to hight power laser diode. But i can not understand how to designe the circuit constand current. Can you help me about it?
baothanh123 is offline   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On











Loading








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes






Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 01:21 PM.


Powered by: vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC