Step-down regulator

[ltktomas]

Hi, does anybody know what chip it is? I've tried searching R8110, E6883ERT etc. but without success.

I need to lower the current that the IC feeds into those LEDs but without datasheet I'm not able to find out which resistors set the current.

[Zero999]

Hi, does anybody know what chip it is? I've tried searching R8110, E6883ERT etc. but without success.

I need to lower the current that the IC feeds into those LEDs but without datasheet I'm not able to find out which resistors set the current.

Try reverse engineering the schematic. Even without the data sheet for the IC, it's normally fairly easy to figure out, which resistor is used for current sensing.

[bborisov567]

If the leds are wired in series you can just add a resistor to limit the current.

[voltsandjolts]

R1 and R2 look like they might both be 560 milli-Ohm.
Perhaps they are wired in parallel to make a 280 milli-Ohm shunt.
In that case, removing either R1 or R2 should half the current.

[esepecesito]

I've seen same question in reddit. Seems a custom chip. Probably better to reverse engineer the circuit and use an alternative.

[ErwinsCat]

my guess is one the resistor near u1, probably r1IIr2

[ltktomas]

I tried reverse engineering the schematic and here it is.

Rest of the board is a horn circuit.

[Zero999]

I tried reverse engineering the schematic and here it is.

Rest of the board is a horn circuit.

There are errors in the schematic, but R1 & R2 are low value resistors and will be used for current sensing. If one of them is removed, it will halve the current.

[ltktomas]

Yes, that did the trick.
I replaced both resistors for one 0.47R and it's much better. Thanks for help