To be deleted

[nul-points]

thanks for the update, Itsu

average readings (apart from their lower values) still suggest that our circuits are different (ie. your Isupply and Iin are similar, whereas my values show that Ifb as the difference between Isupply and Iin)

ok, so it doesn't look like the missing energy is being radiated significantly

yes, i use the same method for 'NO feedback' tests


np

[itsu]

NP,

Hmmm,  i would of thought that you would be pleased with my average results as according to me they present
exactly what you were saying (or do i understand you wrong?).

My average values are:

Isupply = 4.07mA,
Iin        = 4.74mA,
Ifb       = 0.80mA

so indeed like you say, "Ifb as the difference between Isupply and Iin"  well, almost.

Itsu

[nul-points]

hi Itsu

ah ok, i must have seen that the feedback current RMS value looked like the previous table (approx 2mA) where the math wasn't identified (just labelled as current(mA) and thought that value hadn't changed - my apologies!

yes, those values are a closer fit to the pattern of the circuit behaviour


thanks
np

[nul-points]

QUESTION2: Do the capacitor supply draw-down tests support the general comparison seen on this circuit when using another method (eg. scope math)?
ANSWER: Yes they do...

the 1F (nominal) supply capacitor was identified as having an actual capacitance of 1.111F, using the draw-down time for a 681 ohm resistor (and then using online calculation)

the start and end values for charge on the 1.111F cap for the tests was as follows:-
4.0V  4.444Coulombs
3.4V  3.777Coulombs

The total value of charge transferred was:
  (4.444 - 3.777) = 0.667Coulombs = 667mCoulombs


runtime for circuit WITHOUT FEEDBACK: 68.4s
667mC => 667mAs / 68.4s = an average Isupply of 9.75 mA for 68.4s

runtime for circuit WITH FEEDBACK: 90s
667mC => 667mAs / 90s = an average Isupply of 7.4mA for 90s


the CSR traces show that charge transferred from the supply is comparable for both cases:
WITH FEEDBACK: positive pulse (14.6mA for 9.6us) = 137.24uC
WITHOUT FEEDBACK: positive pulse (10.6mA for 12.72us) = 134.8uC

BUT in the 'WITH FEEDBACK' case, 24.4 uC are ALSO transferred BACK to the supply to be re-used;
whereas in the 'WITHOUT FEEDBACK' case, NO charge is recycled

the result is that the runtime of the 'WITH FEEDBACK' lasts around 20-30 % longer, with the same average power delivered by the supply to the circuit throughout - ie. some of the total energy converted is recycled to perform approx 20-30% more work

it appears that this 'WiThFeedback' circuit is able to gather energy which would otherwise have been dissipated and lost, and re-use it to do extra work

energy is conserved - work is not!


np

[itsu]

NP,

nice analysis, i like it.

it appears that this 'WiThFeedback' circuit is able to gather energy which would otherwise have been dissipated and lost, and re-use it to do extra work

But, to my understanding, considering your: "gathered energy which would otherwise have been dissipated and lost"  this dissipated energy also did work to get dissipated.

Not sure yet in which form (heat, light, radiation), but it was doing work then.


So would you not say that you utilized this "dissipated and lost energy" by using feedback and so improving on the overall efficiency (input versus work done) of the circuit?


Itsu