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Analog switching of power with low quiescent current switch

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PeterEE

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Hi,

I am asking advice on the following issue:

I need to switch two external power sources ( 5-12 V) and ( -5 to -12V) on and off with a microcontroller (3.3V). The maximum current to expect is around 300 mA.

The first thing that comes to mind is to use ordinary MOSFETs to do this.

Since the quiescent current of the switch must me as low as possible. I was wondering if there is better way to do this.
If MOSFETs are the way to go, is there something to consider to minimize the current consumption.

Attached you find a simple drawing to clarify what I mean.

Thank you very much for any advice!
Peter

 

The first thing that comes to mind is to use ordinary MOSFETs to do this.
Since the quiescent current of the switch must me as low as possible.

Right. In off-state you have only leakage current, in on-state a few ten .. hundred microAmps.
 

Below is the LTspice simulation of a circuit using two N-MOSFETs and two P-MOSFETs for high-side switching a plus and minus supply from one +3.3V control signal.
All the FETs should be logic-level type that will fully turn on with Vgs=3.3V.
The circuit draws only leakage operating current in the OFF condition and just the current through R1 and R2 in the ON condition.

Pwr Switch.GIF
 

Thank you very much for the help and sharing the circuit ... I appreciate !

Peter
 

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