Author Topic: P-Channel MOSFET always on  (Read 685 times)

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Offline AankurTopic starter

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P-Channel MOSFET always on
« on: May 16, 2022, 09:06:07 am »
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
 

Offline Zero999

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Re: P-Channel MOSFET always on
« Reply #1 on: May 16, 2022, 10:26:06 am »
There are three most likely possibilities:

1) One or both of the MOSFETs is bad.

2) One or both of the MOSFETs is connected backwards.

3) Your multimeter is measuring the tiny leakage and it will be fine.
 

Offline VooDust

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Re: P-Channel MOSFET always on
« Reply #2 on: May 16, 2022, 11:49:05 am »
to measure this properly, you need to connect a dummy load from your output to ground. You can use a resistor for that.

 

Offline strawberry

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Re: P-Channel MOSFET always on
« Reply #3 on: May 16, 2022, 06:00:09 pm »
1uA DS leakage current - 100k resistor = 0.1V + noise
0.6Vgs(threshold)
 


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