In my design the goal is to create a simple switch between power sources using a MOSFET.
- J2 is just a connector for the main power source which remains connected
- VDD is connected to a USB port
- VREG is a voltage regulator that requires the Capacitor there for switching applications. It takes in 5 -30 V in and outputs 3.3 V
- The LED should automatically light up if power flows through VREG that outputs 3.3 V
- The MOSFET used is DN2450K4, an N channel MOSFET
The goal is that the main power source is always connected but if I needed to program my overall device I would plug USB in and the MOSFET should cut/redirect the main power to ground and the USB should be powering the regulator.
When I tested this application with no main source attached and the USB connected to power the LED wasn’t lighting up, so I knew my VREG wasn’t receiving power. The MOSFET was slowly heating up though. Now my question is how can I change this circuit / MOSFET layout to better suite my application?
EDITED AGAIN: I changed MOSFETs. Now I'm using a P channel MOSFET AOD417 (DATASHEET) and switched some wires around based on the finds from this post HERE! I also added another diode D4 to block the charging possibilities of the USB (VDD) to the other source MVOLT