Boost or no boost?

I've done some basic searching here (first 2 pages of "boost" results) and didn't see anything relating to this, so please forgive me asking if this is something everyone already knows:

When do you need to use a boost driver, versus just a driver? If I've got the M140 445nm module from DTR, and a 1.8A linear driver from Mohgasm, would I need a boost if I'm only using 1x 18650, but not if I have a host that handles 2x 18650? Am I understanding that it's a minimum voltage thing?

A linear driver needs 2 X 3.7v batteries, and a boost only needs 1. The host dictates the size of the batteries needed.

For some reason, I had it in my mind that you could add a boost driver to a "regular" driver if need be.

You would only use 2 drivers to double the output to the diode. And you must use simular drivers when doubling.

Your linear diver outputs 1.8A, which will result in ~1.4W diode output. If you want to reach a higher diode output you'd add another 1.8A linear driver. If the diode can handle that much current is a different story.

Go to the Buy, Sell, Trade section. The lasers there will give you an idea on how some combinations work.

I appreciate both of your feedback, folks.

I had seen 2x driver setups, and noticed they were both identical, and understand the idea behind that: push each driver easier, and still get desired power, or reach a higher power than would otherwise be possible using only one driver.

This was just me trying to wrap my head around when a boost was or was not needed. Sounds like, if I'm using a host with that would only allow 1x 18650, then I would need to use a boost driver (or get an extension tube so I could go 2x).

Sounds like a good way to melt a linear regulator....

also when using 2 drivers, make sure both are set to the same current, otherwise you will blow 1.

michael.

thinksnow said:

This was just me trying to wrap my head around when a boost was or was not needed. Sounds like, if I'm using a host with that would only allow 1x 18650, then I would need to use a boost driver (or get an extension tube so I could go 2x).

Click to expand...

A boost is only needed when you want to use 1 battery.

If your host takes 1X 18560 battery, and you want to use a linear driver, then you must use 2X RCR123 (16340) batteries to power your linear driver.

The only way to use 2X 18650 batteries to power a boost driver is to wire them in parallel.

Okay, so until my extension tube gets in, I'll use a couple CR123's.

All the more reason to give in and order the massive jayrob heat sink for my busted 2-D Maglite so I can do this the right way.

Thinksnow,

One clarification to Rotten John's answer, but a boost driver needs to be used if you want to use one 18650 (3.7V), *and* you're driving either a 445 or 405 diode. 445 diodes need about 4.5 volts, and 405's need about 6 volts. Since both are larger than the battery voltage (for a single 18650), you need a boost driver, to boost the battery voltage to the diode voltage.

Red diodes however, are different. They only need around 3 volts (i.e., *less* than the battery voltage), so you can't use a boost driver with a red diode and a single 18650. You need either a buck/boost driver (like the flexdrive, which will operate as a buck driver for a red diode), or a buck-only driver, or a linear driver (all of which require the battery voltage to be greater than the diode voltage.)

(Also, there isn't such a thing as a 'plain driver' versus a 'boost driver'. All drivers are either buck, boost, buck/boost (which can either raise or lower the voltage), or linear).

Hope this helps,
Andy

This is a very interesting thread, now the question that rises to my mind is how do you actually adjust the desired voltage and current in a driver? Are there like two pots or what...

Read this thread. There is already a lot of information about drivers, http://laserpointerforums.com/f67/how-laser-diode-drivers-work-explanatory-thread-71513.html