I have designed a circuit according to the reference circuit found in the ADP1613 datasheet. Attached is my schematics and PCB.
Problem is that when i power the circuit, my PSU current-limits even though no load (ive tried bleeder resistors, doesnt work). Even 500mA or current limit will do. This suggests to me that there must be a short circuit somewhere.
I have tried everything i can think of; altering compensation loop, added capacitance on soft-start, disconnected frequency pin from VCC to try both frequencies. double checked the component solder joints, double checked schematics vs. reference design. Nothing can bring the device out of its non-working state. I have tried three of them, all with the same problem. My PCB is professionaly manufactured, the soldering is professional.
Enable pin works. Adding 10uF on softstart gives a very slow start, but when the device hits a certain voltage, current limiting occurs.
This has come to a point where it drived me crazy. Is it something that i am missing?
I'll be happy to provide more details...
My schematic diagram
PCB top side
PCB bottom side (there is a battery charger there too, only C20 SS cap is relevant)
Please help me!