Makita charger flyback controller identification

[nightmechanic]

Hi All,
I have a Makita DC10WD charger (US version) that I opened up to figure out how to convert it to 230V (actually doesn't need any work except the mains plug  )

During the "reverse engineering" i tried to do I encountered a device with "funny" (custom?) marking - according to its connections it seems to be the flyback controller, its in a SOT23-6 (or similar) package and as you can see marked with a (rather unique according to my experience and web search) 72-63-22 marking.
from measurement it is a 65kHz device.

out of curiosity - does anyone have any idea what part this actually is?
Thanks!

[xavier60]

No, but Richtek is one possibility. Pin 3 can have different functions between different part number ICs.
http://www.richtek.com/assets/product_file/R7735/R7735-04.pdf

[stj]

check the datasheet for an sp6853

that's what is in the Ryobi chargers.

[duak]

Nothing to do with input voltage but I repaired one like this one from a cabinet shop that had been dropped while charging.  The step down transformer broke loose from the PCB and severed one of the secondary wires.  This popped the switching FET.  I was able to re-attach the wire, replace the FET and make it go again.  I can't recall exactly what I did to hold the transformer down but it was probably epoxy and some sort of tie wrap or plastic gee gaw.

Cheers,

[Inverted18650]

I’ve repaired a pallet of OnePlus Charger from Ryobi and they all had the Top256EN controller.

[stj]

must be newer, if seen inside 4 different charger types and not seen that - so that's the 5th variant!

do the idiots still use a pair of schottky diodes in parallel on the output??

[nightmechanic]

must be newer, if seen inside 4 different charger types and not seen that - so that's the 5th variant!

do the idiots still use a pair of schottky diodes in parallel on the output??

I didn't look at the output (I was mainly interested in the input circuit and whether it needed changes to support 230V operation ).
I will check next time I open it up...

[stj]

well that's the common failure point on that variant,
i have fixed 12 now - always the same cause.

2x 5A diodes in parallel, one fails and dumps the full load on the second causing it to short-out.
then it blows the output fet and probably the zener across the fet.

my fix is to fit a single 25A+ schottky diode in a TO220 package with a small heatsink on it inplace of the original diodes.