P-Channel MOSFET always on

AAnkur

New Member
Hello

I am using a MOSFET driver circuit with SI2303 as p-channel mosfet and SI2302 as n-channel mosfet.

I have given control signal (of 5V) on the gate of n-channel mosfet to turn-on and off the p-channel mosfet.



However, the p-channel mosfet is not getting off and I am constantly finding voltage on Output (marked as Point-A).

Please let me know what is the problem in this circuit.

Thanks
 

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Double check the connections? Those devices have internal diodes between source and drain, that will conduct if the two terminals are reversed.
 
If you are measuring with a DMM, no output load, you will read a voltage
because of this -




There is still some drain current. And this does not account for leakage in the NMOS MOSFET Idoff
current at its Vgs = 0. Which can cause a non zero Vgs in the PMOSFET.


Regards, Dana.
 
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