Quick sanity check - please! ;-)
I have a circuit that's designed to be powered by 12vdc, and has a 5vdc converter to supply the digital side with 5vdc. It's also got an USB input to provide power to the 5v side.
Problem is that the damned thing ties the 5vd from the rectifier to the 5 vdc from the USB - which is in my mind a potentially "bad thing".
My though was to simply pop a PNP transistor onto the 5dvc USB feed, and tie the base to the 12vdc supply side so that when it's on, the transistor is off, so disconnecting power from the 5v side of the USB.
Am I missing something here, or will this work?
I have a circuit that's designed to be powered by 12vdc, and has a 5vdc converter to supply the digital side with 5vdc. It's also got an USB input to provide power to the 5v side.
Problem is that the damned thing ties the 5vd from the rectifier to the 5 vdc from the USB - which is in my mind a potentially "bad thing".
My though was to simply pop a PNP transistor onto the 5dvc USB feed, and tie the base to the 12vdc supply side so that when it's on, the transistor is off, so disconnecting power from the 5v side of the USB.
Am I missing something here, or will this work?