I'm trying to implement og test the results discussed in the linked JeeLab post in a low power battery powered device. http://jeelabs.org/2013/05/18/zero-power-measurement-part-2/#comments
The post describes a method for monitoring the battery voltage through a voltage divider that can be switched off by a P-channel and a N-channel mosfet. Similar solutions are discussed here:
Low Current Battery Monitor Detail Question
Low current battery monitoring
The question is how do I select an optimal N-channel og P-channel mosfet for this application? Which electrical parameters should I base the component selection on? If anyone have experiance with this method and/or selection of components sharing would be appreciated.
Answer
Check reverse leakage in datasheet. I would not use a mosfet for "true zero" power devices, but a NPN (PNP) bjt, with the same base capacitor trick.
A zero base current (or under Vbe) will easily ensure some nA collector current. This kind of devices you can see in car remote controls, where a NPN is connected directly to battery, while applying (OOK) modulation to base.
Use LtSpice to simulate.
See this Low Drain-Source MOSFET Leakage
SIMULATED
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