Switching a high voltage with a lower voltage

Thread Starter

Oarc

Joined Mar 29, 2012
2
Hello everyone,

This is my first time posting on these forums! I have done my research although I don't know why this was so hard to find out. There were a lot of answers similar to what I was trying to do but were not exactly what I need. I don't really have another few hours to spend searching for a good solution so I am kindly requesting your help for my simple problem :)

I'm working on a project in which I need to switch a sensor on/off using an MSP430. The MSP430 I am using (MSP430F2003) outputs a max of ~2.6 volts when it's on. The sensor requires a 5 (+/- 0.5) V to operate. My power supply is a stack of AA batteries which totals to ~9V. I have a voltage regulator which takes the 9V and outputs 5V.

I was initially planning to use an NFET between the 5V voltage regulator and my sensor. However, the NFET drops the voltage by more than .5V, closer to 1V... I then realized I was incorrectly using the NFET and that it probably won't be able to do what I need...

I attached a simple circuit showing where the switch needs to be, but it needs to be controlled by a 2.6V signal somehow. Since this is for a low power application, fewer components and low quiescent consumption would be great. The image includes the part numbers I have, and I left the NFET off to the side because I don't think there is a way to solve my problem with JUST the NFET.

Even if you could just point me to the answer somewhere else, I would appreciate it. Thanks in advance! Also let me know if my question wasn't clear enough and I'll try to better explain it.
 

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Thread Starter

Oarc

Joined Mar 29, 2012
2
Thanks for the idea! I'll look into it!

Meanwhile, I also got help from a professor who works at 9pm :)

I'll post back here with my final design in week or so. Thanks for the quick response!
 
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