P-Channel MOSFET always on

[AAnkur]

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

 

[Harald Kapp]

Show the FET pins (S, D, G). When you swap D and S, the body diode will be conducting. We cannot see this since you haven't used the conventional MOSFET symbols which makes it difficult to read your "schematic".

 

[crutschow]

Yes, sounds like you have the P-Channel source and drain reversed.
The source must go the the +12V.

 

[CircutScoper]

Hello

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


Thanks

What is the magnitude of said voltage and with what kind of voltmeter are you measuring it?

Even when off, mosfets, like any real switch, will have a bit of leakage. The S12303 datasheet speaks of as much as 100nA, which would produce a reading of 1V in a standard 10Megohm input impedance multimeter.

If this mysterioius voltage is of the order of 10s to 100s of millivolts and you're measuring it with a high input impedance meter, try adding a 10K resistor from output to ground. It might disappear.

 

[Harald Kapp]

@AAnkur : Without replying to our questions you cannot expect more help.

 

[ETechnoG]

Check the following points,

1. Polarity of connection
2. Components are in good condition
3. Is there any short circuit
4. Is transistor goes into breakdown mode