James said:
Hi All,
Thanks for the good responses to my previous post.
I have a project that I am looking at that requires 1ma at 3V. I want
to see if I can use a calculator solar cell for charging the circuits
battery. I can not find any good information on calculator solar cells
on the web. It seems like they should be in volume production and not
to expensive. Anyone know what voltage the solar calculators run on?
Anyone know where to find information or data-sheets on calculator
solar cells?
Thanks,
James
I am looking at the same sort of solutio path for a battery operate
people sensor using a wirless outbound link for energy savings. The
battery is critical as it enable installation of the sensor pod o the
ceiling where the 'view" is better, alas not much line power there.
In the past we struggled to keep the 2-3 years on four aa alklines. Tis
time we want to etxned the life >4 years.
The new cpus all like to work at 3.3 ot 2.6 volts so we use two cells.
interacing with 3 volt logic to real world analog presents its own
problems. Some technology is not there yet, relays etc.
Then we worked real hard to chop 10 ^13 eelctrons from each and every
signasl path. then the next generation op amps 1-2 uA instead of
10u30uA. Then the snesor element itself consumed the most curent so it
was trimmmed so that the sensor and the amplifier(s), and signal
processor had eqaul currents. Then we have parts of the circuit
tri-stated at time redcuing power dynamically, and finally once detetion
takes place and is valid we latch a flip flop and turn the analog off.
The net is that we copnsume 60uW now down from 15 mW. Your calulator
uses somthing like 10-50uA and that s what enables the solar power (tiny
per cm^2) to be able to power a handhedl calculator.
I have a solar panel that stores inot a super cap, and I ahve it
trickling power now. I plan to use Pulsed power techniguees to store and
chrage..for a time.. and then dump inot a proper energy sore and
re-chargin well. I can collect 200uA in diffuse room light. and can
charge up in 142 seconds and this would run the unit (with a 1 volt
depletion) for over 18 minutes. while useful you can only count on 6-8
hours of diffuse light. therfore I need to capture moe than i need to
use in hours and trcikle it in over 16 hours, or tke the sow dissapation
in the primary cell.
James, if you would like to keep the onversation going write direct to
[email protected] Marc popek
