Hi all, This is the driver from my Maglite ML300LX 2D. I suspect its a boost/buck because I can run this light on a 3.7v Li-ion just fine, and it does not effect the output.
Does anyone see components on here I could potentially swap out to get an increase in drive current?
Yes, TPS63020 is a buck-boost IC.
The large resistor without marking is likely the sense resistor.
Have you measured the output current?
Thanks for responding. I’m getting about 550 ma to the LED. (EDIT: That cant be right, something must be wrong with my DMM, I will try again and get back to you)
I assume you mean this one?
Do you have a guess as to what I might add to it or swap it out for?
I’ve never had another one of these apart, but I am guessing the driver in all their lights is the same or similar. I see the ML300L 4D has an output of 1000 lumens which is double what the ML200LX has. So hopefully this driver can handle double the current. 1.0-1.5 amp or so?
This also has me very curious as to what the maximum input voltage for the driver might be.
Yes
That seems too low for a 500lm light.
Something must be wrong with my DMM, or my test. I just realized that cant be the right current.
I must have had a loose connection, or a glitch with my clamp meter. I measured again and this time I got 1.4 amp.
If I am not mistaken the ML300LX is using a Cree XML3. So that would be more in line with the rated output of 487 lumens (which I have confirmed is an accurate rating)
I fear that might be near the maximum TPS63020 can handle at low input voltage.
63020 has 5.5V max Vin, the MCU is probably 5.5V, so that much.
So even if I run this on a lithium ion cell we are stuck at the 487 lumens?
Anyway, because there are no marking on the sense resistor. The process would be to measure the output current and measure the voltage (Vsense) across the sense resistor, preferably at the same time with another DMM. if not at the same time then measure med and low modes too and check that the calculations match with high measurements.
It’s just ohm’s law
Rsense=Vsense/Iled
Then for the the sense resistor for the new current :
newRsense = Vsense/newIled
No, with li-ion you can up it to 3A.
Edit : also dont measure at low input voltage, say 3V min, to be sure the BB IC isnt throttling the output below the target regulated current due to input overcurrent.
Thank you for the input. I was not able to get a measurement across the resistor, because to test the driver outside of the switch takes 6 connection points, including the two for the switch which is on the opposite side of the board as the resistor I need to test.
I have a multitude of of various resistors in a wide range of values. I am thinking about just soldering another resistor over the top of the factory one, to see if I get an incremental gain.
If you had to guess, what value do you think would be safe to start out at? I don’t care if it takes several tries for me to get it right, I just don’t have even a ball park idea of what value to start at.
This is the driver out of a 4D. I am wondering if it can handle higher voltage like 2x li-ion? Can you tell by looking at the components?
@thefreeman ^^^
