Power on/off for single device in the project

[bokzsamot]

Hi

I am making a project, in which I use gps module. The problem is, that this module is using very rarely, so I want to implement some solution, that enables me to switch on/off power supply for only this device, using microcontroller pin. I am aware, that the answer for this question should be very simple, but I don't know how to do it. I have found some examples with mos transistors or relays, that seem to be simple, but I don't know if is it a good way.
The microcontroller, that I am using, is msp430F149. Both gms and uC are powered from 3V.
I hope, I haven't made a lot of mistakes and You can understand me I am still improving my language skills.

 

[D.A.(Tony)Stewart]

Find max. current on GPS then see if any ports can switch that directly on uC, otherwise use a n-type FET switch on high side ( V+.)

 

[crutschow]

Find max. current on GPS then see if any ports can switch that directly on uC, otherwise use a n-type FET switch on high side ( V+.)

For high side switching of a positive voltage you need a P-MOSFET. And to switch 3V you need a logic-level type MOSFET that fully turns on at 3V (that's not a Vgs threshold of 3V).

 

[dick_freebird]

There are IC products referred to as "power strobe" or
"load switch" meant for exactly this kind of thing. You
probably could even use something like an ACS or LVC
logic family hex inverter (all in parallel) to get a tolerable
on resistance if the powered load is reasonably low.
Or an octal bus driver, those are mighty beefy (in logic
terms anyway) with about 5 ohms series resistance
per driver, under an ohm net in parallel, and you could
choose between tristating (float the load) or 1/0 (load
is discharged when off).

Of course shuttling all the bypass capacitor charge in
and out could become more wasteful than letting the
radio sit idle (DC) depending on cycle rate. That's a
trade decision for you to make. Might look into whether
the radio has enough internal power management that
you could be happy just using its enable pin, or
something, as well.