Doubts regarding power supply requirements for GPS receiver

Batter Charger Circuit

I have some basic doubts reg power supply requirements for a GPS Receiver. It needs 3.3 V regulated Power supply. Im currently using a 3.3V 300 mAh battery.
Is there a way to generate 3.3 V Regulated supply as easy as using 7805 for 5 V supply. I even looked at MAX 756 IC but it is not available near my place.
Can anyone suggest an alternative?

Is it possible to supply +5V and -5 V (i mean enabling or disabling a voltage inverter. pls include a voltage inverter circuit link if u have one) from a microcontroller pin.
TU

Added after 2 minutes:

One more doubt.
Can anyone help me in designing a charging circuit for a 3.6 V 300 mAh battery?

Re: Power supply doubts

If you mention 7805, that is a linear regulator. Try some of these parts from National. www.national.com/VCatalog/view.cgi?...Current//v:8&as=0&render=1&c=&domains=PNumber
Linear Technology also has lots of linear regulators suitable for 3.3V.

As a negative charge pump you can use the ICL7662 for example: www.intersil.com/data/fn/fn3181.pdf
To turn it off you can use a transistor in series with its input power and simply turn off that transistor using your microcontroller. Either a PNP or a logic level P-channel MOSFET will work. The MOSFET is a better choice, since it does not need a resistor and it draws no additional current. Again, other charge pumps are available from LT, TI, Maxim. Some of them have an on/ off pin.

As for the battery, you need to know what chemistry it is to implement a correct charging algorithm. There are many deicated IC's, some of which can handle multiple chemistry. Visit the LT, TI websites.