Bad idea ?
I have an automotive application that requires a pic and circuit that will run at 5V and draw MAYBE 50ma alltogather.
I was thinking I could use the 12v in, tie it to a resistor (4.7kish) then reverse the zener to ground, to that between the diode and the resistor I have a 5V source.
This is buffered 12v so I am not worried terrible about spikes, but they may still occur duing startup.
This zener says its good to 1W. I figure my deal will be using ~.3W.
This is mainly to get away from using a 5V regulator. Which I have niether the money or space for (mainly space, so please dont tell me how cheap they are). Another reason for not going with a regulator is that this unit will always have power running to it, day and night, the pic will sleep most of the time but I have a feeling the regulator will draw more power then I'de like. (If possible I'de like to be at or under 1ma when sleeping)
I have an automotive application that requires a pic and circuit that will run at 5V and draw MAYBE 50ma alltogather.
I was thinking I could use the 12v in, tie it to a resistor (4.7kish) then reverse the zener to ground, to that between the diode and the resistor I have a 5V source.
This is buffered 12v so I am not worried terrible about spikes, but they may still occur duing startup.
This zener says its good to 1W. I figure my deal will be using ~.3W.
This is mainly to get away from using a 5V regulator. Which I have niether the money or space for (mainly space, so please dont tell me how cheap they are). Another reason for not going with a regulator is that this unit will always have power running to it, day and night, the pic will sleep most of the time but I have a feeling the regulator will draw more power then I'de like. (If possible I'de like to be at or under 1ma when sleeping)