Hi, I am trying to control an RF SPDT switch which has two control voltage pins V1 and V2. The truth table for the SPDT is attached. Now what I want to achieve is controlling the opposite voltages (0v and -5V) using two p-channel mosfets to deliver these voltages. The gate of the mosfets will be connected to an output pin of a microcontroller which has a voltage of 5V at logic level 1. I was able to set up such a circuit in a simulator however only with positive voltages. Once I make it -5V it all becomes a bit counter-intuitive for me.
If i set the voltage sources to -5V then the mosfets never turn off obiously, no matter what i set my logic to because:
Logic0 (0V gate): 0-(-5) = 5V= Vgs
Logic1 (5V gate): 5-(-5) = 10V Vgs
How would I tackle this issue? any help in the right direction is very helpful. thank you
edit: i have looked all over the internet for controlling mosfets with a negative supply I cannot find anything. But maybe i am googling the wrong words.
If i set the voltage sources to -5V then the mosfets never turn off obiously, no matter what i set my logic to because:
Logic0 (0V gate): 0-(-5) = 5V= Vgs
Logic1 (5V gate): 5-(-5) = 10V Vgs
How would I tackle this issue? any help in the right direction is very helpful. thank you
edit: i have looked all over the internet for controlling mosfets with a negative supply I cannot find anything. But maybe i am googling the wrong words.
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