[EMAIL PROTECTED] wrote: > with standard battery we get a standby of 1200 / 0.6 = 2000h max. Sounds > quite > neglectable, but like Andy said, every bit of current counts. It's all > summing up.
Whoa, that's the MPU going full blast all the time. [EMAIL PROTECTED], here we come ;-) If the MPU can sleep every once in a while, we get a low-power mode that's about three orders of magnitude more battery-friendly. > We can handle this. Have the MPU at some booster that's to be leveled down > from e.g. 3.0V default to sth like 1.8V, what is task of the MPU to set up > PMU. Yeah, with an LDO, we'd just burn the power elsewhere, so it should be a switching supply if we really care about power consumption there. Not sure if there's anything really nice and small out there, though. Maxim have a bunch of boost converters that don't look too bad, e.g., the MAX867EUA+T [1] (3.3V, 3x5mm footprint). Needs external caps, inductor, and diode. The tiniest I could find is the TI TPS62700YZFR [2] (3.09V or adjustable 1.6x1.5mm), which doesn't even need an external diode. But it's not cheap, and it burns 300uA on its own, basically negating any gains we could get. [1] http://datasheets.maxim-ic.com/en/ds/MAX866-MAX867.pdf [2] http://focus.ti.com/lit/ds/symlink/tps62700.pdf > All the other chips will have additional FET-low-R switches (one for > each powerline that need it) to protect them from OV I don't think the PCF50633 ever pulls strongly to GND. It normally uses a weak pull down if the regulator is off, though. > Some VoltageDetection for PowerGood if we can spend. So far, we got away with what's inside the PMU :-) - Werner
