About a year ago “tritan67” asked about the soft start on the power supply in the “DC/DC Converter - 5V 5W (R-78E)” product page.
I’m interested as well. I’ve spent some time looking on-line. Some of the solutions would cost more than the R-78E itself.
I’ve found that an NTC is a simple solution but that can waste a lot of power.
I was thought of using a P-channel MOSFET parallel to the NTC, to bypass the NTC after “startup was complete” (turn on the MOSFET using an output from the controller … since it’s there anyway).
I also found a circuit in “Using MOSFETs in Load Switch Applications” (https://www.onsemi.com/pub/Collateral/AND9093-D.PDF). Do you think I could just leave out the N-channel and simply calculate the resistor & capacitor values to limit the inrush current to 1A?
What do you think of these solutions?
Do you have another circuit suggestion?
Thanks, Joe.