Electronic – 3.3v high side switch


I want to replace my relay with a high side MOSFET switch. I am a new to all this and I don't know how to choose the components.

The load needs around 200mA at 3.3v with the control coming from a open collector pin on a microcontroller. After some searching I found the following circuit. How do I modify this to run at 3.3v instead of 12v?

enter image description here

Best Answer

You can regard R1 and T1 as the microcontroller's open-collector (actually it's open-drain) output, then you only need the pull-up resistor R2 and the P-channel MOSFET. Since you're working at low voltages you need a logic-level gate FET.