Quick question about regulated drivers

Gather App
Candle Power Forums

Help Support Candle Power:

0

021411

Enlightened
Joined
Mar 3, 2007
Messages
715
City & State/Province
The Lone Star State
I apologize for this noobish question..

If a light is driven with a regulated 3.6v-6v driver and running on 2 primaries with a total of 6v, is there a set voltage the driver is running at even though it's seeing 6v from the batteries?

Would there be a difference running say a LiIon battery at 3.7v in brightness if the driver is regulating anyway?

Does that make any sense? :shrug:
 
Hi 021411,

No need to apologize that's how we learn is by reading, and asking questions.

The short answer is yes, in most cases. Take for example a driver using a 7135 chip set that has the voltage range you specified. The driver will basically limit the current to a set out put until the voltage drops below a certain point where it will fall out of regulation ( usually around 3.6ish volts) and then be direct drive. The only advantage to running the higher voltage is you would get a bit longer max out put time.

An example of this would be 3 aa cells would run a light with a 7135 driver set to 1400 ma at max for the frist part of the cycle, lets say 1 hour. If you put 4AA behind that same driver you would not get any longer run time, but you would stay regulated to the 1400ma for a longer time because the voltage of 4 AA would remain above 3.6v longer than the 2AA.

If the driver you are talking about happens to be a true buck converter rather than a chip that just burns off the extra voltage(probly not in this case since the v range is only to 6V) you would get longer run time with the 4AA as well.
 
021411 said:
I apologize for this noobish question..

If a light is driven with a regulated 3.6v-6v driver and running on 2 primaries with a total of 6v, is there a set voltage the driver is running at even though it's seeing 6v from the batteries?

Would there be a difference running say a LiIon battery at 3.7v in brightness if the driver is regulating anyway?

Does that make any sense? :shrug:
Click to expand...

Drivers comes in two flavours: Buck and boost.

Buck can reduce a voltage and boost can increase a voltage (There exist also a combination buck-boost that can do both, but it is seldom used).

I.e. a led with a Vf of 3.6 volt will have full brightness from a little bit above 3.6 volt (Due to driver loss) and up with a buck driver.
In my reviews (Mostly in Danish and found on my website) I often do a voltage scan to see how the driver works at different voltages, most buck drives can not keep full brightness when the supply gets close to Vf.
 
I see.. So in the case of the 3.6v-6v regulated driver, 3.6v is the minimum required level from the batteries for "full power". As soon as the battery drops below 3.6v, it runs in direct drive. But as long as the voltage from the batteries satisfy the range of 3.6-6v of the driver, it's okay and running at optimum levels.
Now I need to find a rechargeable battery (17670) capable of sustaining at least 3.7v for a good while.
 
021411 said:
I see.. So in the case of the 3.6v-6v regulated driver, 3.6v is the minimum required level from the batteries for "full power". As soon as the battery drops below 3.6v, it runs in direct drive. But as long as the voltage from the batteries satisfy the range of 3.6-6v of the driver, it's okay and running at optimum levels.
Now I need to find a rechargeable battery (17670) capable of sustaining at least 3.7v for a good while.
Click to expand...

In theory, but in praxis I would not count on it being able to keep full power at 3.6 volt, at least not without testing it.
 
HKJ said:
Drivers comes in two flavours: Buck and boost.

Buck can reduce a voltage and boost can increase a voltage (There exist also a combination buck-boost that can do both, but it is seldom used).
Click to expand...
Linear regulators also reduce voltage but are not buck drivers.
 
HKJ said:
I have written some more about drivers here.
Click to expand...
Lots of good information in that thread! :twothumbs (I remembered a Dane had written it and wondered if you were the one.) Any chance of fixing the last few spelling errors?
 
TorchBoy said:
Any chance of fixing the last few spelling errors?
Click to expand...

Sorry, but I can not do that, the spell checker says everything is correct and it is much better at English than I am. I know that my English has some problems and if you send a pm with corrections, I will take a look at it.
 
You must log in or register to reply here.

Latest posts

Back
Top