Hi all,

What's the best way to calculate battery life if boost converter is evolved=
..=20

1. I have boost converter that starts at 0.9v and batteries I used are 2xAA=
=20
    at this moment I have 2 rechargeable batteries each one is 2000 mah tot=
al=20
voltage battery side
    is 2.4v and output of boost converter is 3.3v
   standby current boost converter takes 6ma assuming every thing else is=20
disabled or in sleep.
   I made a mistake in schematic by not enabling burst mode. it suppose to =
be=20
38uA on stand by mode not 6ma. LTC3402
   mod can be done but any time I do the mod the chip burns out.=20
2. I use PIC24FJ256GB110 according to datasheet it takes 1ma run time assum=
ing=20
2v power but the clock is not mentioned so I do not know.=20
    I am using 4mhz 3.3v and run time takes 5ma. I changed the crystal to 1=
mhz I=20
see very small difference in load. I used 4mhz
    only because of USB requirement. I am able to switch internal clock to=
=20
4.000.000 when usb is not used and 48.000.000
   when usb is plugged in.

my question is how should I calculate battery life based on 8ma load since =
there=20
is a boost converter that runs at 0.9v and=20
I know from passed that 80% of battery should be used. I know its rated as=
=20
current per hour lets say

80% of 2000ma =3D 1600ma/0.008ma=3D200.000 hours

I am just adding extra 2 ma incase of enabling other IC chips.
does this make sense? 200.000 hours

thanks

AA


     =20
--=20
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