5v for PIC problem

[financecatalyst]

Hello
I need some help to design a transmitter using an RF Transmitter module and my PIC12F635. Problem is I have been given a 12v battery and I need to provide 12v to the module and 5v to PIC - All upon button press as to spend no current while no button is being pressed.

My guidelines are to minimise current consumption as well - I have tried using 7805 but my current consumption (eventhough its momentary) is HUGE 70mA ( my little 12v battery drains in few days upon few clicks every day).

My project makes PIC pins high upon corresponding button press, upon which depending on which pin is made high - corresponding data is sent.

I Hope someone can help!

Thanks

[aratti]

First of all replace the 7805 with a low drop regulator (LT1086 series for instance).

If you post the schematic you could have a little more help.

Al.

[inse]

I think a better choice for low quiescent current would be a LP2950 voltage regulator.
The LT1086 (similar to the 7805) needs 5-10 mA, the LP2950 less than 100uA for himself.
Are the 70mA constanty drained into the PIC or also the rest of the circuit?
You can put your PIC into sleep mode and reduce the current consumption to a few uA.
If you make your transmitter circuit switchable by the PIC you should be able to reduce the standby current to the 100uA range.
If this is not sufficient, I've seen circuits where the uC switches off its own power supply and is powered up by a key-press.

Regards,
Ingo

[amgen]

I think there is something wrong with your circuit set-up to draw 70ma. A 78L05 uses only few ma's. Are you using 10k to 100k r's to the pic pins that select which switch is pressed ? PIC enabled transmitters I have have made only consume about 10 ma.

don
amgen

[financecatalyst]

Thank you all for your input!
I managed to reduce the current now to 12mA