What are the best driver boards?

[Probedude]

Yes, but I don't know about "waste" since you're getting what you want out of them, so it's more a necessary cost. Whether it's more, less, or just the same efficiency as a buck or boost board will depend on input voltage.

Hmm, there's no energy conversion so except for Vin being close to Vout I'd expect it to always be less efficient than a switching solution. With Vin < Vout (impossible with this board) there's additional losses through the voltage drop across the series pass transistor.



Dave

 

[TorchBoy]

there's no energy conversion

Any regulator will convert electricity to heat. Actually, some do quite a lot of that.

except for Vin being close to Vout I'd expect it to always be less efficient than a switching solution.

If your switching solution is only about 60% efficient you don't even need the Vin close to the Vout for the linear regulator in question to be more efficient. Switching does not necessarily mean efficient, you know. :nana:

the voltage drop across the series pass transistor.

... is supposed to be only 0.12V, so it'll run much closer than your typical buck board, with the inherent high efficiency. This is why I think making that list of regulator boards is needed. People just don't seem to understand when one type will be better suited than other types.

 

[Spypro]

Thank you all of the advices.

I'll buy some SSC P4 and a 4 pack of the #3256 driver board from DX. I'll mod my Scorpion LED (will be difficult since I almost destroyed the module) and I'll use 2 x RCR123 in it. My other mod will be my Mastercraft Maximum. Is the #3256 board ok to run with RCR123 ?

Thanks !

 

[Probedude]

Any regulator will convert electricity to heat. Actually, some do quite a lot of that.

Sorry, I meant power conversion. As in Watts in - Watts out. Amp draw on a linear driver will always equal the amps out ignoring quiescent current no matter what. At least with a switcher the amps in can be less than the amps out if Vin > Vout (and with efficiency in your favor). Also with linears Vout can never be greater than Vin.

If your switching solution is only about 60% efficient you don't even need the Vin close to the Vout for the linear regulator in question to be more efficient. Switching does not necessarily mean efficient, you know.

agreed and it varies with current draw. A well designed switcher though can run in the high 90%.

... is supposed to be only 0.12V, so it'll run much closer than your typical buck board, with the inherent high efficiency. This is why I think making that list of regulator boards is needed. People just don't seem to understand when one type will be better suited than other types.

Yep that would be helpful. I looked at the datasheet for the 7135 current regulator and it does have an impressively low voltage drop. The dissipation out of the SOT89 case is limiting though and per the datasheet the recommended sq in of copper plane is decently large. I don't know if much conduction happens through the body of the pill using such a board. One side has the contact for the battery + to touch and the other side has the components so there is not a large contact area for heat conduction to the pill.

 

[TorchBoy]

OK, with a view to someone (maybe not me) starting a list, when people are looking for a regulator board, what are they normally looking for? Something that will work with a given battery or input voltage range? Something that will output a certain current (range)? Something with multiple modes or that could easily be modded for that? By input voltage sounds like the simplest way to list them.

 

[Probedude]

OK, with a view to someone (maybe not me) starting a list, when people are looking for a regulator board, what are they normally looking for? Something that will work with a given battery or input voltage range? Something that will output a certain current (range)? Something with multiple modes or that could easily be modded for that? By input voltage sounds like the simplest way to list them.

Just keep adding columns for the features and other specs but yes, sort by the input voltage.

 

[yellow]

dont think that list makes sense.
ppl should be able to look for themselves at the drivers that are currently available!

f.e. if You make that list and someone reads (that I suggest) the Flupic as the BEST driver overall for single led and Li-Ion. Not only because of its diversity,
but especially with the question in here:
because it seems to get into some kind of direct drive when the cell is around 2.9-3 volts and current decreases more and more from then
(I once wanted to try it out with an unproteced cell and got down to only 2.7 V under load because it lasted so long I got bored and stopped somewhen)

whats the give?
Guy knows there was a good driver and will not be able to get it.
Perfect

 

[TorchBoy]

Sorry yellow, I don't understand your post.

Anyway, I've started a list. And it is just a start - there must be dozens of drivers around. It'll be interesting to see how the format changes over time.

 

[Spypro]

It is sometime hard to choose a driver and it is not always well documented on the websites.
I saw the list and it is great !

 

[snipinglight]

Those boards appear to use linear voltage regulators. If so don't they waste power by dissipating the difference as heat? I see no inductor.

Dave

Can I know what are inductors in the circuits used for?

 

[Lynx_Arc]

Inductors work on the theory of transformers. They convert higher or lower voltages in pseudo AC. They conserve more energy than just dissipating the extra energy to heat. The buck circuits convert the DC to a crude form of AC and them reduce (transform) the voltage lower while increasing the current then the AC is converted back to DC for use.

 

[TorchBoy]

Inductors ... conserve more energy than just dissipating the extra energy to heat.

:sigh: Of course, inductors themselves dissipate energy as heat and regulators based on them are not necessarily efficient at a particular voltage, even if they are in one voltage range.

So one more time: If there's not much extra voltage there won't be much energy to dissipate as heat, so non-inductor solutions (linear regulators) can be a much more efficient option.

A circuit having an inductor is not some magical pathway to efficiency. Drewfus2101's tests of buck P60 drop-ins and linear regulators show this quite nicely. Which is better to use in any given situation will depend on input voltage (and sometimes current), output voltage and current, and price.