Hallo everybody!
I have designed a SEPIC Converter with the following specifications:
Vin: 3-8V, Vout: 5V, Iout: 0.3A
The design works fine, exept with an Input Voltage of exactly 4V! If the Input Voltage crosses 4V, the Output Voltage drops down for about 1 second. after this time, the output comes back to 5V. Neither it matters from which side the input voltage crosses 4V, nor which current is drawn at the output, the circuit behaves still in the same way. Around about 4V Input Voltage there must be an big issue with my design.
The main components (inductor, diode) are the one that have been suggested in the ADIsimPower design tool. Cin and Cout are both 20µF in size (two paralleled 0805 ceramics, 10µF, X5R)
I also tried to change the compensation network and choosed a bigger inductor, but nothing changed at all.
any suggestions what i could try further?
Thank you
Michael