.:madworm:.'s photos with the keyword: PT4115

and fully cleaned.

So far I've managed to kill 5 of these PT4115 LED drivers, and I don't think that I've abused them - at least when compared to what I've done to other devices that survived no problem. The failure mode is very consistent. Either it stops working altogether (no more switching, output switch permanently open) or the output switch is permanently closed and the LEDs suffer over-current. Common to both manifestations is that the DIM pin shows unusually low resistance (about 6Ω) to GND. This makes me believe that this pin gets trashed somehow. Therefore I will test if adding a Zener + dropper resistor will help to protect the chip. Voltage clamping at 5V1 definitely works, so lets see how things go. Adding a Zener + resistor is the way to go. No more premature demise.

The result is pretty good. I think I could use an even smaller tool (spear-point drill). Using sub-1mm fluted end-mills can get a bit tricky, especially if they're not of the short and stubby kind. They break quite easily - and cost a lot.

1k dropper resistor + 5V1 Zener diode BZX84C5V1.

I've added a signal wire going to the 'dim' pin and wires getting the rectified voltage.

And it does work. I'm using a tiny BSS138 MOSFET and the usual PWM output to drive this board. Works perfectly, doesn't heat up. 12V 1.8W

This time I just soldered a wire to the 'DIM' pin (otherwise floating) and connected that straight to one PWM output.

Read potentiometer and adjust one PWM output accordingly.

This time I just soldered a wire to the 'DIM' pin (otherwise floating) and connected that straight to one PWM output.

Same board, but different types of LEDs.

There's a face, yes I can definitely see a face on the board.

It is still missing a few important parts... power connector + labels, footprint for optional soft-start capacitor... If you should have an idea what else to put on there, let me know. Keep in mind that these modules should be 'dumb' and there will be another board which is supposed to control them (PWM dimming, maybe IR receiver or PIR sensor). The board is designed to run at 24V DC (or a bit less) and will draw about 100mA. Total light output should be 180lm. If the cooling via the copper pour is sufficient, I might increase the current a bit.