Help needed modifying circuits

I need help, anyone who is good with circuits, can you tell me how to boost the power/current to this circuit, I think it is 2400Mah .. I want 6A .. I've added photos below..

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6 amps is a lot of current, so I'd address the other areas of the light first with spring wire mods and thicker LED leads. As far as the driver, those stacked resistors looks like they're sense resistors, and swapping in lower resistance resistors, stacking more or shorting them should increase current output of the driver.

leaftye said:

6 amps is a lot of current, so I'd address the other areas of the light first with spring wire mods and thicker LED leads. As far as the driver, those stacked resistors looks like they're sense resistors, and swapping in lower resistance resistors, stacking more or shorting them should increase current output of the driver.

Click to expand...

The high current isn't an issue, I've done spring mods, will be doing thicker silicone wiring once the driver is done, I've soldered a Noctigon MCPCB directly to the pill, so all that's sorted the light can handle the current, I'm just not great with the circuit it's self, which resistors do I short?

That's good to hear that you're taking care of the rest of the circuit. I just wanted to make sure. You might not want to short it. I'm just saying that sometimes that's an acceptable alternative to stacking more resistors, but I don't think that'll apply to this driver. I'll pm you a link to a recent thread where HKJ explains how to choose which resistors to use.

It's unlikely that a circuit designed for 2.4A will survive running at 6A. There are several components that would not likely survive - the main power transistor (whether discrete or integrated), the diode (which I can see, is a 3A diode), the inductor...

I would recommend starting with a beefier driver, or using multiples.

But if you really want to try, the resistors in the middle marked R430 and R270 are the sense resistors, as Leaftye says. You need to have a lower value. What we can see are a 0.43 and 0.27 ohm in parallel, but it looks like there are more beneath. You want to replace with lower values, or just add some more.

As you reduce the overall sense resistance, the current goes up proportionally to the inverse of the resistance. So does the power dissipation in the total sense resistance. The power dissipation in other things goes up MORE than proportionally. In the diode it goes up as the 1.2 or 1.3 power of the current, in the FET and the inductor it goes up as the square of the current. (6/2.4)^2 = 6.25 times the power!

Thanks Leaftye and DIWdiver, if I just took the resistors out completely and just left a solder trace would that work?

No, that would result in an infinite current.

That would be really bad. As one of my professors used to say, that would create an annihilation wave that would propagate through the universe at the speed of light.

It'd definitely increase current...until the smoke escapes. Sometimes it's okay, but that's when there's already very low resistance sense resistors there, and even then it doesn't always work. You should know what resistors are there and do the math to figure out what to change.

So say I take out all the sense resistors then replaced with x3 0.12R resistors what current output would that give me, I've been looking everywhere for info but I'm not the best with circuits, I'm still learning :twothumbs
Is there a formula for calculating sense resistors?

OR

If my driver is running at 2400mAh now and I add in x3 0.12R resistors (I read that a 0.12R outputs 417mAh?) then that is 417mAh x 3 = 1251mAh + 2400mAh = 3651mAh so my driver is boosted from 2.4A to 3.6A? Is this correct?

And the same goes with using a 0.1R (which I read is 500mAh) so say 4 500mAh resistors= 2000mAh + 2400mAh = 4400mAh so the circuit would put out 4.4A?

Is this correct?

You're just making wild guesses until you know what resistors are on that driver right now.

The regulator circuit is designed to control the current until it creates a specific voltage across the sense resistor. That's typically between 0.05 and 0.2V. You can use Ohm's law to calculate the resistance if you know the voltage and the desired current.

V=I*R, or R=V/I, where R is the resistance, I is the current, and V is the voltage.

If you know the output current of the thing as it is now, and can read all the resistor values, you can calculate the regulation voltage (also called the feedback voltage, or sense voltage).

To calculate the resistance of several resistors in parallel, use the formula:

1/Rtotal = 1/R1 + 1/R2 ... +1/Rn

DIWdiver said:

No, that would result in an infinite current.

That would be really bad. As one of my professors used to say, that would create an annihilation wave that would propagate through the universe at the speed of light.

Click to expand...

Of course, the very first thing that would get annihilated would be your driver...