[Tinyos-help] DVcc on TelosB/TmoteSky when powered from USB

Hi all, I'm trying to profile the power consumption of the TelosB mote when powered from USB. I've looked at the schematics of TelosB but I could not figure out how the DVcc is generated when powered through the USB. In addition, I would also like to know where is the Vccin (which is fed to diode D

Re: [Tinyos-help] DVcc on TelosB/TmoteSky when powered from USB

Boy, that's a tough one...I'm not entirely sure without looking up all the chips but I think when powered by the USB it goes sorta like this: page 3 top-left "USB Interface" U22 pin 4 -- power from host -- becomes U_VCC U25 TC55RP33 -- does some magic to make -- P_DVCC page 3 top-right "Mote Pow

Re: [Tinyos-help] DVcc on TelosB/TmoteSky when powered from USB

Michael is correct here: the power from the USB connector U4 (about 5V) goes through a U25 which is a voltage regulator that produces 3.3V. That voltage goes through the diode so that the USB side of the mote is not reverse-powered when the mote runs on batteries and the mote is disconnected from

Re: [Tinyos-help] DVcc on TelosB/TmoteSky when powered from USB

You have any idea why that diode is (or appears to be) a Zener? And there's a diode-drop issue, isn't there? Just idle curiosity... MS Robert Szewczyk wrote: Michael is correct here: the power from the USB connector U4 (about 5V) goes through a U25 which is a voltage regulator that produces 3.

Re: [Tinyos-help] DVcc on TelosB/TmoteSky when powered from USB

Hi Michael, Actually I believe it was supposed to be a Schottky diode (note the shape of the bar with those tiny protrusions). What would be the concern wiht the diode drop -- there is about 0.3V voltage drop across the diode when the mote is connected to USB (under that scenario, we're not neces

Re: [Tinyos-help] DVcc on TelosB/TmoteSky when powered from USB

At this point I feel I should fall back on "magic" as an answer... I have, occasionally and accidentally, powered MOS circuits through input lines. Maybe there's enough leakage. MS xi zhang wrote: Hi, Thanks for the reply. However, when I remove the D22 diode, the LEDs still blink when powered

Re: [Tinyos-help] DVcc on TelosB/TmoteSky when powered from USB

Hi, Thanks for the reply. However, when I remove the D22 diode, the LEDs still blink when powered through USB. Why is that so? Best Regards, Xi 2007/9/27, Michael Schippling <[EMAIL PROTECTED]>: > > Boy, that's a tough one...I'm not entirely sure without looking up all > the chips but I think wh