Am Mo 30. Juni 2008 schrieb Andy Green: > |> Currently the hypothesis I am trying to work with is that we pull way > |> too much current at power up, and the loss of Vsys is a reasonable > |> response from the pcf50633. > | > | That sounds plausible, yes. I estimated that the systems draws about > | 3W from the capacitor bypassing VB_SYS. > > Wah for how long though? > > |> So where does all the power go? I didn't find out yet (or indeed prove > |> it is true). > |> > | > |> I sniffed around the GSM stuff for a while, because the charger action > |> can basically power it all since it is directly powered from "battery", > | > | Ah, that's an interesting theory. The PMU's GPIOs are stable in > | Standby, so you could control the GSM power switch. However, our > | default should already do this right. > | > | There's something we don't control with this switch, and that's the > | RF amplifier. A radical way to test whether GSM is to blame would be > | to remove B1701 and see what happens. > > I checked the enable for it last night, nothing.
I think it's a great idea to remove/break B1701. RF-power-amp might draw a spike, no matter whether there are enable-spikes anywhere at all. /j
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