Hi, having programmed a picaxe to control my solar tracker, and designed it to minimise power consumption, I now need to power it from the 24v battery (i.e. up to 30+ volts). The problem is that a standard reg like a 78L05 is still spec'd to draws quite a few mA, which kind of makes a mockery of my power saving efforts like putting the pic to sleep at night to save battery power.
I did look into a simple zenner, perhaps with an emitter follower transistor, but the 4.7v zenner I tried doesn't really hold it's voltage at <2mA.
having done a bit of a search for off the shelf low power regulators there are plenty, but they all seem to be low-dropout regs for battery power and the 'best' I've seen had a max Vin of 20v.
So the question is: Is there a simple way to get a stable supply in the range: 3.0-5.0v @ up to 2mA (though a few extra mA might be nice for future projects) from a 24v (up to 30v+) supply, with a low quiescent current (ideally <1mA)?
thx
m
I did look into a simple zenner, perhaps with an emitter follower transistor, but the 4.7v zenner I tried doesn't really hold it's voltage at <2mA.
having done a bit of a search for off the shelf low power regulators there are plenty, but they all seem to be low-dropout regs for battery power and the 'best' I've seen had a max Vin of 20v.
So the question is: Is there a simple way to get a stable supply in the range: 3.0-5.0v @ up to 2mA (though a few extra mA might be nice for future projects) from a 24v (up to 30v+) supply, with a low quiescent current (ideally <1mA)?
thx
m