Simple load switch using FET

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rprodrigues

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Hi guys,

I will use the load switch shown in the picture below to supply current to a 5V / 100mA load.





I made some simulations with PSPICE and the voltage drop across the MOSFET is about 50 mV at 100mA, what is fine for my requeriments.

Am I wrong or the schematic shown is really that simple and enough for my requeriments?

Could I need any other components in the circuit or it's already ok?

It seems too simple I can not believe!


Thank you
 

that's definately not how i would have done it.

what state is your mosfet in when the microcontroller is NOT active (maybe during power up, some failure, etc.)

the 1MEG resistor will cause a long ass time for your mosfet to turn ON due to super small charging current.

i don't really understand why you connected the capacitor like that.

Mr.Cool
 

Indeed Mr Cool,
I haven't noticed this 1MEG resistor in the gate.
It should be c.a. 100 Ohm and the capacitor should be definitely removed.
Also it would be wise to drive your MOSFET's gate from two processor pins like on the drawing below.
This way you'll be safe from from turning On your device when your uC is reset.
Your load will be powered ON only when two control signals ON1 and ON2 have opposite values ( ON1=1 and ON2=0, or the other way around ).
 

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