Hi!
I have a problem with the TPS63050 converter IC. At startup the input voltage is 3,6V and the output voltage stays very low (400-500mV) for a long period of time (10-30sec). Meanwhile the voltage measured on the soft start capacitor increases very slowly up to 1,3V. After this point the output voltage jumps up to the desired 3,3V - and little bit above, because the converter operates always in PFM mode. There is a 10uF cap on the input and 20uF on the output.
I made test with no load, and a 33ohm load resistor for 100mA constant current, but the result is the same: Low output voltage while the SS capacitor is below 1,3V. Also I have assembled two custom board, the result is the same on both board.
My question is why does it take so long time to charge up the SS capacitor to 1,3V?
On a third board where I assembled the complete project, not just the DC/DC converter, this phenomena is vanished. I hope this is not a miracle, and maybe it's related to the overall capacitance on the output of the TPS63050?!
Thank you and best regards,
Levente
