next-generation PMU discussion

joerg joerg.twinklephone at
Sun Apr 20 17:17:11 CEST 2008

Am So  20. April 2008 schrieb Werner Almesberger:
> Andy Green wrote:
> > I guess if we go this way we have to examine the 50633 defaults closely
> > to see what the other options are if any.
> STBYCTL1 and STBYCTL2 don't enable regulators in Standby mode.
> So we need some other way to get from NoPower into Standby, or
> give the MPU its own independent regulator.
> That's why being able to hook it up to battery/USB power would
> have been nice. But yes, we'd burn a bit of power.

Hey no problem: we spend a FET (Vbat) and a Schottky diode (Vcore, whatever) 
for the MPU itself, so it can switch off it's own Vbat as soon as there's a 
better supply - like 1.8V from some converter, or maybe the backup bat 
(probably use the one of PCF50633?)

This way we burn the excessive power only during a few seconds on MPU-boot / 
PMU setup.


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