I evaluated samples of this IC a while ago (Seiko S-882Z24-M5T1G), with hundreds of applications, but Seiko (at least going by the New England rep) won’t sell them except by the reel. Making these available in hobbyist quantities would open up all sorts of possibilities. It would be great for DIY RFID type projects, and other low-voltage sources like single (0.6v) or overcast solar cells, fuel cells, Peltier/Seebeck devices, ambient RF power, etc.
The part is a self-contained charge pump + voltage switch that outputs 2.4V from input sources as low as 0.3V(!). Under normal usage, the output capacitor CPout is gradually charged, then connected to your load when its voltage reaches 2.4V. For light loads, this output can then be maintained indefinitely. For heavier loads or very weak input sources, the load will be disconnected again when the output cap drops below about 1.8V.
The thing that sets this apart from the usual arsenal of boosters such as the Joule Thief circuit (besides 300mV startup) is that it operates well from very low-current as well as low-voltage sources, a situation where most boost circuits fail. That, and the load switching avoids start-up problems from slow voltage ramp-up (e.g. a microcontroller coming “half-on” at 1.2V with an unusually high current consumption, and never getting over the hump).
Datasheet for S-882Z24-M5T1G:
http://www.sii-ic.com/en/product1.jsp?s … uctID=1788
Sample circuit / writeup: http://tim.cexx.org/?p=540
Places that may be able to get it (besides the sales reps)
Mouser, Digikey, Avnet have it ‘listed’, but no stock (and minimum quantity = 1 reel)
http://www.onlinecomponents.com/buy/SEI … Z24-M5T1G/ - these guys claim to sell in small"er" quantity.
A breakout board for this would be simple and make these types of projects accessible to hobbyists - the only required parts are a small (~<10uF) input cap for supply bypass, and a larger one (100uF ~ big supercap) for CPout. Or ideally, just pin out these connections and let the user breadboard their own of the desired capacity.
What do you think?
But as a practical lower bound, as in (100uF ~ sky’s the limit). I have a couple 10F (no typo) *2.3V supercaps sitting on my desk just waiting for a good application, but an msp430 or similar can do a fair amount of work with 100uF at that voltage.