On 3/18/15 11:53 AM, Philip Odom wrote: > Would using a battery charger/management IC be an option for you? > You’re going to need some type of battery charger anyway, right? > There are many of soft-power circuits that use virtually no power > when off, but there are a lot of ICs on the market that will do > exactly what you want (battery management, low battery detection, > switching between dc input and battery, charge battery while running > off DC, etc.).
Thanks, Philip. I'm using a Microchip MCP73831 charger controller now, but it's really simple -- I don't think I can get as much info out of it as I need. (It only has a "Charging" pulldown signal.) I know there are plenty of other chips on the market, but there's a big jump in price after the MCP products when you sort by cost. 50 cents for this component is OK, $2 for the next better chip is not! This is actually the first battery manager chip I've ever used, and I just hooked up stuff last night so I could watch it and see if it was doing what I expected (mostly it was, phew!) > If you do want to use a soft-power circuit, what you described will > work, with the drawback that the pulldown resistor will use power > while the device is on. It can be a pretty large value resistor, > though. If you OR the charger input with a control line from the uC > through diodes, either one can keep the power on without back-driving > the other. Good to know I'm not totally smoking crack. I'm not hugely worried about power draw, except when the devices are in inventory. I don't want them wrecking their batteries before they ever get to the customer. The users will probably charge them every few days or whatever, and once they get months or years of service out, we'll be golden (and we can come up with a better design for version 2). But if version 1 comes out of the box broken because the battery was flatlined on the shelf, we'll never get to version 2! Thanks again! -- Mersenne Law LLP · www.mersenne.com · +1-503-679-1671 - Small Business, Startup and Intellectual Property Law - 9600 S.W. Oak Street · Suite 500 · Tigard, Oregon 97223
smime.p7s
Description: S/MIME Cryptographic Signature
_______________________________________________ dorkbotpdx-blabber mailing list [email protected] http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber
