I am using an Arduino Uno in my project. I recently found that if I disconnect the power from my Arduino (I am powering it by USB port, from a 5V regulator - 7805), then it remains under power from the input pins. I also found that if I disconnect the 3 digit 7 segment common anode display (which is also powered from same 7805) and if I remove the LM358 (which is again powered from the same 7805) from the socket, then my Arduino is not powered anymore. My questions are:
- Is my setup correct - if I am powering it from the 5V regulator (7805) through the USB port ?
- My Arduino and the other components from the schematic - the display, the LM358, the mosfet - will be powered on at the same time, when the 230V switch that is placed on the mains input of the 24V SMPS is closed. Could this be a problem in terms of "phantom powering" ? Is there any better way to power the Arduino when I have 5V regulated supply on the schematic ? I will always keep connected the Arduino to the 5V output of the 7805 to the USB port.
Please find attached 2 schematics, one is the main PCB (the one with Arduino) and the other schematic is the one with the display, which is placed on the front panel. The J2 connector from first schematic is connected pin to pin to the J2 from second schematic.