Understanding the difference between Linear, Buck, Boost and Direct Drive drivers

Flashlight Modding and DIY Parts
2

This is a complicated subject. Even though I know how it works, I may have forgotten something or made mistakes. So please feel free to help me improve this topic! :slight_smile:

3

Great effors, admittedly I only skimmed but I’ll read the entire thing start to finish later this evening.

One thing I see at first tho is your statement in the DD section

This is usually true however not a rule, if an LED with lower vF is used (and the driver components all accept ~1v input [most parts used have ~2.7v minimum]) then you can run that emitter from a lower power cell. For example I have an ATTiny 13V (low power version of 13A) MCU and use it to run a DD FET driver from a 1.8V lithium primary driving a red rebel LED. If you could find an led with a 1.2 or 1.5vf you could drive those with a DD setup.

4

True. I had in mind the Cree LEDs that need 3V…

5

Looks like there is an issue in the boost section under advantages.

Note I’m not trying to say you wrong about anything, thanks for your efforts here, just trying to help you improve this for others.

Thanks for doing this!

6

I’m not taking it the wrong way, you are helping me to produce something accurate and helpful to others! So thank you. :slight_smile:
I corrected the mistakes you pointed out.

7

I feel like there is too much text. I just installed Matlab and KiCAD. I’ll try to make some nice graphs to explain the same things with less words… But not today. :slight_smile:

8

Nice explanation, I think it is a good introduction for folks who are new to building flashlights, but I guess someone who is completely new to this should judge that :-)

Thanks for the write-up!

9

I don’t, it’s a in-depth subject.

If you want to redo it with less text that’d be cool but I urge you leave everything already up. Make a new post with the shortened version, you should never remove reference material.

10

I did also do an article about it a couple of years ago (Date says 2010): http://lygte-info.dk/info/DriverTypes%20UK.html

11

Thanks for the support guys! I see that somebody already linked to my topic so I’m happy. :slight_smile:

12

I somehow never found this article on your website, even though I looked through it many times.
Anyway, I added a link to your article at the bottom of the OP.

13

That article was only posted on CPF and I wanted to update it before posting it on my website, but has never gotten around to do that. Maybe you can use some ideas from it (I might still update it and post it sometime in the future).

14

Lagman, you may consider going a little more in-depth on the PWM section and go into duty-cycle some.

15

Thanks for taking the time to put all this great information together.

16

I might do a separate in depth topic on this. I don’t want this to be so long that it scares newbies.

On a side note, I have a doubt about my title. Would it be better to say:
“Understanding the difference between Linear, Buck, Boost and Direct Drive drivers”
Instead of:
“Understand the difference between Linear, Buck, Boost and Direct Drive drivers”
?

17

Yes, not really wrong as is but adding “ing” wouldn’t hurt, no ones going to complain tho.

*native speaker but not an English teacher or anything

18

So both are correct but the one with “ing” sounds better?

19

Nice summary, i like it.

20

applaud the topic: it’s an instruction, ‘do this’ (works fine in your title, as “you can do this”)
applauding the topic: it’s a description, ’we are doing this” (also works fine in your title)

21

Thank you! In that case I think I’ll put “Understanding” as it fits better what I intended to say.