2009/10/14 Werner Almesberger <wer...@openmoko.org>: > Aaron Carroll wrote: >> BL is the backlight, with I measured across R1763, and V at C1764. > [...] >> BL = 14.38 V, 28.53 mA, 410.26 mW > > Is the BL voltage what you measure at LED+ relative to GND or have > you already subtracted LED- ? In the former case, your result would > be about 10% high with maximum backlight.
LED+ to GND, because I want to include the power lost in R1763. >> IN is measured at the battery with no other external connections, >> with the current measured via a 100mohm resistor in series with (+). >> The power is just the product of the quoted V/I. > [...] >> IN = 4.01 V, 252.89 mA, 1014.09 mW > > Which side is IN - battery side of the shunt resistor or Neo side ? > In the former case, you'd be another 6% high. I can't see which shunt resistor you are refering to, but the measurement is taken at the battery connector (i.e. CON1701). > Regarding expected efficiency, the 50633 manual is silent about it, > the 50606 manual has the following data: > > Current Conversion > (mA) 3.6 V -> 1.8 V 3.6 -> 3.3 V > 1 75% 92% > 10 85% 95% > 100 85% 96% > > Up conversion seems to have similar characteristics as down > conversion, but the voltages given don't make sense (Vi = 5.0 V > and Vp = 1.8 V. That's a down conversion !) > > So we should expect an overall conversion loss of not much more > than 25%. The 50606 converter has a much lower peak voltage/higher peak current... can we make a meaningful extrapolation here? Cheers, -- Aaron _______________________________________________ hardware mailing list hardware@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/hardware