Been a while since I have been on here but I do not know where else to turn for help! This is more of a hardware issue than anything so i do hope that I am in the correct forums to be asking, if anyone knows of somewhere else I should be looking for help please let me know!
Anyway, this circuit simply drives a 10W RGB COB LED, using an esp8266 as the micro which then controls 3 MOSFETS via PWM that drive each channel of the RGB LED.
LED: (This is not the same manufacture that i am using but specs are the same) http://www.ledguhon.com/u_file/images/14_11_25/57d628dfd6.pdf
The input voltage is 12 - 15V AC as these are powered by low-voltage AC landscape transformers. The input is then ran through a full wave bridge rectifier followed by a 1000uF capacitor in order to produce DC voltage. This is then followed by a buck converter that drops that voltage down to 10V DC in order to drive the LED. 3 Constant current drivers are then used for each channel of the RGB LED in order to produce 350mA for each channel.
Constant Current Drivers: https://datasheet.octopart.com/AL5809-50P1-7-Diodes-Inc.-datasheet-76802127.pdf
The issue I am having is with the Red channel, in my last batch of 50 of these boards I have more than 10 that the red channel has stopped working on. They work at first and then over time some of them the red channel begins to flicker than just shuts down. Oddly enough if i press on the LED it self the red channel will turn back on but again fails as soon as i let go of pressure. ( I have checked all solder connections and everything seems to be just fine, ive even re-soldered some) I am not sure if this issue is due to a bad batch of LEDs or if i have an issue with my PCB design / circuit. Below are my schematics, the resistor R6 is 10 Ohm, 3W. The second buck converter is used to drop the 10V DC to 3.3V for the esp8266. Also A1 - A9 are the constant current drivers. A1-A6 AL5809-50P1-7 & A7-A9 AL5809-150P1-7 (PN's Located in data sheet link above).
These two PCBs then clip together to form the final assembly, The reason for the two separate boards is the heat generated by the LED needs to be far from the esp8266.
If you need more information or have any questions on the board in order to assess the problem please let me know! I could write an entire book on the function of this board but I am trying to keep it short and sweet.