[ltp] X61 power consumption

[Richard Neill]

Asheesh Laroia wrote:
> On Fri, 28 Nov 2008, Leszek Koltunski wrote:
> 
>>> That would be rather difficult, as in order to measure the power, you 
>>> have to measure current and that means cutting the power connection 
>>> to the chip, to insert the meter in series.  Now if you wish to 
>>> volunteer your ThinkPad to be butchered...
>>
>> Oh, come on, I am not an electrical engineer, but I am sure it's 
>> possible to do that in a non-invasive way, for example doing precise 
>> thermal imaging of the mainboard.
>>
>> It seems to me such hardware-level measurements would be very 
>> enlightening...
> 
> And indeed, if someone wants to do this and has experience and know-how 
> but lacks some hardware (possibly just lacking a ThinkPad to test), I 
> could possibly be inclined to put money toward buying it....


Having thought about this a bit more, I reckon the equipment could be 
obtained for about $25. 3 cheap digital voltmeters, an op-amp, some 
resistors and batteries should be enough. [If someone wants to do the 
experiment, I'll write a longer post.]

That would let one measure the power consumption of a given chip to 
within < 10% accuracy, in a calibrated manner (provided that the PCB 
traces carrying the current can be acccessed - which isn't necessarily 
true for BGA chips).

Richard