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 > Drivers, Test-load, Power Supply, & Batteries



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



Reply
 
LinkBack Thread Tools Display Modes
Old 04-18-2015, 09:04 AM #1
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default Inverting buck/boost - Case Positive Diode Driver

Inverting buck / boost drivers have always hurt my head, but as I think about it, I'm starting to wonder whether this variant if switching driver may actually be the solution for case positive diodes.



The V- essentially becomes continuous with the LD+, even though technically they're never part of the same closed circuit. Out seems to me that you could have the LD+ attached to the host, and the host would actually be tailcap negative (which sounds strange, I realize).

What am I missing? Wouldn't this work?


__________________
CURRENT WAVELENGTHS:
405|441|450|467|473|495|505|520|532|556|PGLRG|589|594|632|638|660


SAFETY & IMPORTANT READING (threads authored and contributed to by various members of LPF):
- Federal Aviation Administration - Laser Safety Initiative (link)
- Info release from Laserglow - Default Canadian restrictions on portable lasers (link)
- The Necessity of Safety Goggles (link)


Last edited by rhd; 04-18-2015 at 07:32 PM.
rhd is offline   Reply With Quote







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







Old 04-18-2015, 05:25 PM #2
djQUAN's Avatar
Class 3R Laser
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
djQUAN djQUAN is offline
Class 3R Laser
djQUAN's Avatar
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
Default Re: Inverting buck/boost - is this the easy answer for case positive diodes?

It will work but the current control loop / current sense IC would be a nightmare unless you figure out a neat trick or something.
djQUAN is offline   Reply With Quote
Old 04-18-2015, 05:31 PM #3
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default Re: Inverting buck/boost - is this the easy answer for case positive diodes?

Quote:
Originally Posted by djQUAN View Post
It will work but the current control loop / current sense IC would be a nightmare unless you figure out a neat trick or something.
And here's the neat trick I'm thinking of:



Long story short, we buck in constant voltage mode, using the approach the boost/buck IC is expecting rather than trying to make inverted current sensing work (which I hurt my brain trying to problem solve, and didn't end up with a workable solution to). Rather, we get current control via a continuous-positive linear like an AMC7135, after the fact. Bucking to 3.75V gives us efficiency so that the linear is just doing a little bit of work controlling current.
Attached Thumbnails
Inverting buck/boost - Case Positive Diode Driver-schem.png  
__________________
CURRENT WAVELENGTHS:
405|441|450|467|473|495|505|520|532|556|PGLRG|589|594|632|638|660


SAFETY & IMPORTANT READING (threads authored and contributed to by various members of LPF):
- Federal Aviation Administration - Laser Safety Initiative (link)
- Info release from Laserglow - Default Canadian restrictions on portable lasers (link)
- The Necessity of Safety Goggles (link)

rhd is offline   Reply With Quote
Old 04-18-2015, 05:55 PM #4
djQUAN's Avatar
Class 3R Laser
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
djQUAN djQUAN is offline
Class 3R Laser
djQUAN's Avatar
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
Default Re: Inverting buck/boost - is this the easy answer for case positive diodes?

Yes I think that would work. Although I think there should be a pot to adjust output voltage to be able to trim off right at the dropout voltage and the differences in diodes.
djQUAN is offline   Reply With Quote
Old 04-18-2015, 06:49 PM #5
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default

Quote:
Originally Posted by djQUAN View Post
Yes I think that would work. Although I think there should be a pot to adjust output voltage to be able to trim off right at the dropout voltage and the differences in diodes.
I'll add that.

Unfortunately, AMC7135s don't scale well, you just have to keep adding more, so this approach becomes bulky at higher currents. I thought about adding the traditional MOSFET + transistor current source, but that adds a 0.7V drop.

EDIT: Here's a first pass at a board. It's proof of concept only (large, only setup for 350mA). But if it works, then at least we have a boost-buck driver that can run case positive diodes, and can scale up to 5A or so before size becomes too obnoxious. If it works and people use it, it's going to drive everyone nuts that they'll be attaching the battery (-) to their tailcap, even though the diode is case (+). I'd expect a lot of confused forum posts!



Attached Thumbnails
Inverting buck/boost - Case Positive Diode Driver-board.png   Inverting buck/boost - Case Positive Diode Driver-schem.png  

Last edited by rhd; 04-18-2015 at 07:20 PM.
rhd is offline   Reply With Quote
Old 04-19-2015, 05:03 PM #6
djQUAN's Avatar
Class 3R Laser
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
djQUAN djQUAN is offline
Class 3R Laser
djQUAN's Avatar
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
Default Re: Inverting buck/boost - Case Positive Diode Driver

Looks good.

Scale up to 5A? that's a lot of AMC chips in parallel

With the same PCB, it may be possible to get 700mA by putting another right on top of the existing AMC chip. Or even 1050mA if you're adventurous
djQUAN is offline   Reply With Quote
Old 04-19-2015, 05:13 PM #7
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default Re: Inverting buck/boost - Case Positive Diode Driver

Does anyone know how the AMC7135 internally works such that the voltage drop can get so low? Can we replicate that? I thought about using a MOSFET current regulator schematic but swap the transistor for a germanium transistor so that it wouldn't drop 0.7V. But it turns out germanium transistors are hard to find in SMD.
rhd is offline   Reply With Quote
Old 04-19-2015, 05:26 PM #8
DashApple's Avatar
Class 3R Laser
 
Join Date: Jan 2009
Posts: 1,353
Rep Power: 5965
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
DashApple DashApple is online now
Class 3R Laser
DashApple's Avatar
 
Join Date: Jan 2009
Posts: 1,353
Rep Power: 5965
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
Default Re: Inverting buck/boost - Case Positive Diode Driver

looking at the data sheet , in the basic diagram it uses a very low resistance N channel mosfet as the pass item

I have no idea about the switching regualtor stuff but Could you use a LDO controller and a external pass mosfet to give you the low dropout regualtor your after , ideally the same as the 7135 but with a external mosfet ( with higher current capability ) ?
__________________


Stuck In The places I Hated The Most , Reboot My Memory , Restart My heart , Seal Up All Of My Wounds Take Me Back To The Start !
Rip Me To Peices , Replace What You Can , Bury The Rest And Build A New Me To Plan !

Last edited by DashApple; 04-19-2015 at 05:54 PM.
DashApple is online now   Reply With Quote
Old 04-19-2015, 08:56 PM #9
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default Re: Inverting buck/boost - Case Positive Diode Driver

I wonder if this works? Everything about it looks wrong, but I think it might work given that the the final output portion is linear regulation... why not regulate on the (-) rail of the LD output.

Attached Thumbnails
Inverting buck/boost - Case Positive Diode Driver-schem.png  
__________________
CURRENT WAVELENGTHS:
405|441|450|467|473|495|505|520|532|556|PGLRG|589|594|632|638|660


SAFETY & IMPORTANT READING (threads authored and contributed to by various members of LPF):
- Federal Aviation Administration - Laser Safety Initiative (link)
- Info release from Laserglow - Default Canadian restrictions on portable lasers (link)
- The Necessity of Safety Goggles (link)


Last edited by rhd; 04-19-2015 at 09:06 PM.
rhd is offline   Reply With Quote
Old 04-20-2015, 12:52 AM #10
Benm's Avatar
Class 4 Laser
 
Join Date: Aug 2007
Location: Netherlands
Posts: 7,428
Rep Power: 15904
Benm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond repute
Benm Benm is online now
Class 4 Laser
Benm's Avatar
 
Join Date: Aug 2007
Location: Netherlands
Posts: 7,428
Rep Power: 15904
Benm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond reputeBenm has a reputation beyond repute
Default Re: Inverting buck/boost - Case Positive Diode Driver

The general concept of using a switchmode driver with negative voltage output does work, which would solve problems driving 808nm pump diodes in hosts where the negative battery terminal is connected to the case.

There is little need to complicate things by using an inverter first and following that up by some sort of linear driver.

As far as dropout voltages go: the can be very low of a negative-side driver like 7135: no need to overcome the B-C voltage of 0.7 volts at all, only the E-C voltage is in the way which could be as low as 0.2-0.3 volts for a bipolar silicon transistor, and near zero for a FET.
Benm is online now   Reply With Quote
Old 04-20-2015, 01:09 AM #11
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default Re: Inverting buck/boost - Case Positive Diode Driver

Quote:
Originally Posted by Benm View Post
There is little need to complicate things by using an inverter first and following that up by some sort of linear driver.
That's good news. I look forward to your thoughts on how to achieve current regulation without the linear driver tagged on the end. That's what I struggled with.
__________________
CURRENT WAVELENGTHS:
405|441|450|467|473|495|505|520|532|556|PGLRG|589|594|632|638|660


SAFETY & IMPORTANT READING (threads authored and contributed to by various members of LPF):
- Federal Aviation Administration - Laser Safety Initiative (link)
- Info release from Laserglow - Default Canadian restrictions on portable lasers (link)
- The Necessity of Safety Goggles (link)

rhd is offline   Reply With Quote
Old 04-20-2015, 02:58 AM #12
Hiemal's Avatar
Class 3R Laser
 
Join Date: Dec 2011
Location: Houston, TX
Posts: 1,449
Rep Power: 311
Hiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond repute
Hiemal Hiemal is offline
Class 3R Laser
Hiemal's Avatar
 
Join Date: Dec 2011
Location: Houston, TX
Posts: 1,449
Rep Power: 311
Hiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond reputeHiemal has a reputation beyond repute
Default Re: Inverting buck/boost - Case Positive Diode Driver

Alternatively, if current sensing is an issue to begin with, why not just flip the ZXCT around so that it still gets a "positive" current measurement to read?

It shouldn't know the difference, since it's just a matter of making sure it gets to read a positive potential relative to ground. Then you could just make it like any other switchmode CC driver, without having to add the additional bulk of a LDO or linear or another transistor.
__________________
formerly Le Quack


Drivers and Stuff

Superboost Driver (5.5+ amp capability) End all for Boosting!

MicroSized Boost Driver

Low Dropout Linear Driver


Any electronics related questions?

Send me a PM and I'll try my best to answer!
Hiemal is offline   Reply With Quote
Old 04-20-2015, 03:27 AM #13
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default Re: Inverting buck/boost - Case Positive Diode Driver

Quote:
Originally Posted by Le Quack View Post
Alternatively, if current sensing is an issue to begin with, why not just flip the ZXCT around so that it still gets a "positive" current measurement to read?

It shouldn't know the difference, since it's just a matter of making sure it gets to read a positive potential relative to ground. Then you could just make it like any other switchmode CC driver, without having to add the additional bulk of a LDO or linear or another transistor.
It sounds great, and that's what I initially thought of doing, but start trying to actually implement that, and you'll see that there's no way to drop it into the the inverter circuit such that it doesn't interrupt the V- / LD+ common connection, and creates a voltage at the IC's FB pin that is 1.25 (or 0.8 or 0.6, or whatever the FB voltage is) above the IC's ground.

Give it a shot. You may have more luck than I, but I don't think it's as straight forward as you've suggested.
__________________
CURRENT WAVELENGTHS:
405|441|450|467|473|495|505|520|532|556|PGLRG|589|594|632|638|660


SAFETY & IMPORTANT READING (threads authored and contributed to by various members of LPF):
- Federal Aviation Administration - Laser Safety Initiative (link)
- Info release from Laserglow - Default Canadian restrictions on portable lasers (link)
- The Necessity of Safety Goggles (link)


Last edited by rhd; 04-20-2015 at 03:28 AM.
rhd is offline   Reply With Quote
Old 04-20-2015, 12:18 PM #14
djQUAN's Avatar
Class 3R Laser
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
djQUAN djQUAN is offline
Class 3R Laser
djQUAN's Avatar
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
Default Re: Inverting buck/boost - Case Positive Diode Driver

I still think the AMC chip is the best option here.

edit: how about this? http://cds.linear.com/docs/en/datasheet/3083fa.pdf

Last edited by djQUAN; 04-20-2015 at 03:37 PM.
djQUAN is offline   Reply With Quote
Old 04-23-2015, 03:45 PM #15
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default

Quote:
Originally Posted by djQUAN View Post
I still think the AMC chip is the best option here.

edit: how about this? http://cds.linear.com/docs/en/datasheet/3083fa.pdf
The challenge with that IC is that it disrupts the common (+). The AMC doesn't, which is why it works well here. I can't see a way to make that Linear chip common positive.
rhd is offline   Reply With Quote
Old 04-23-2015, 04:07 PM #16
djQUAN's Avatar
Class 3R Laser
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
djQUAN djQUAN is offline
Class 3R Laser
djQUAN's Avatar
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 559
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
Default Re: Inverting buck/boost - Case Positive Diode Driver

Quote:
Originally Posted by rhd View Post
The challenge with that IC is that it disrupts the common (+). The AMC doesn't, which is why it works well here. I can't see a way to make that Linear chip common positive.
The LED driver in the examples page is continuous positive.

Attached Thumbnails
Inverting buck/boost - Case Positive Diode Driver-led.png  
djQUAN 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 03:24 AM.


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