Hacking the KD 2.8amp driver

[Packhorse]

I have used the this KD driver many times. I seems like a cheap OK driver.

I really like the 3 modes, low volt warning (6volt?) and over temp warning.
Some have complained about it over heating and causing problems although I have never has this happen to me.

I have driven it off 7.4v Li Ion packs. 9.6v NiCd packs,11.1v Li Ion and 12v NiMh and PB packs.


I have also used it to drive 7.4v 2.8 amp loads ( 4 XR-E's 2P2S or 1MCE and 3 XR-E's) at 9.8 and 11.1 volt input.

I would be interested to know if it can drive 11.1v loads at 2.8 amp and what input voltage it would require.
I heard that someone swapped out a capacitor to be able to do this reliably but couldnt find any more info.

Also can it be hacked to put out more or less current?

As a side note the last 5 units I got from KD had no positive button in the centre of the driver.

 

[mash.m]

hi,

i used this driver very often for my mods. but if you wan to use 4 lion cell you must change a cap. i can make i picture if you want.

i think you can get more output, but the driver is with 2.8 amps at his thermal limit.

as i know you need 2-3volt more input then output. i used this driver most for one mc-e setups. but two dies seriell and two parallel so you get 1400mA per die.

markus

 

[Packhorse]

Yes. Specs on what cap to change and what to change it to will be great thanks.

1400ma per die on a MC-E? How reliable is that?
I run 4 XR-E's in the same configuration in a dive light with no issues.

I'd like to try 3 P7's or MC-Es off 1 driver. But the Vin would need to be 13v+

 

[Der Wichtel]

I'm not sure but I got some ICs from Axlite as samples and it seems like the KD driver is using the same IC.

However I couldn't go over 8V as well with my setup. From the specs it says it can handle up to 3A but there is no configuration for 3A in the datasheet. The sensing resistor table stops at 1.4A...
With 1.4A it works fine. The IC is really good. They just should have excluded the internal mosfet which is a p channel type with high rdson which is why the IC gets hot.
The should have routed the gate drive pin out in order to use better external mosfets...

the good thing of this driver is that it has some kind of logic integrated. It is not fully analog. The frequency it generates is constant so inductor selection and routing path design is easier. Furthermore it turns the mosfet full on when the input voltage is under the output voltage (direct drive).

I think using two of these drivers in parallel and setting each to 1.4A will work fine

 

[mash.m]

They just should have excluded the internal mosfet which is a p channel type with high rdson which is why the IC gets hot.
The should have routed the gate drive pin out in order to use better external mosfets...

hi,

the pictures on kaidomain are not the right ones. the driver had an external fet. as i wrote, i used this driver very often. and in some build at more then 15 volts (4 lion cell in series). i take some pictures today and upload it.

markus

 

[Packhorse]

..... i can make i picture if you want.....

Any progress with the pic?

 

[mash.m]

hi,

now the picture with the marked cap that must replace if you go over 12-15 volts. picture shows the driver from the front and backside:

please use a cap with a low esr for high ripple applications. i always used a non smd cap from an old computer mainboard with 10µF

markus