To be deleted

[itsu]

I added some more measurements onto the spreadsheet.
I also removed the very first one as that one seems wrong as i probably did not follow my measurement protocol.

But i don't think that like Void mentions it is inaccurate.
We are talking about milli-volts and micro-amps deviations, so pretty accurate if you ask me.

_{Anyway, here it is:}

Itsu

[itsu]

time to recap on the original circuit we're looking at here (and which Itsu is kindly looking at replicating)

i'm attaching an overview of the circuit - it has 1 supply branch and effectively 2 branches (ignoring a higher impedance biasing branch with an effective impedance of approx 10k ohm at 130kHz)

one branch is entirely a current drain, Iin, on the supply and the other is entirely feeding current, Ifb, back to the supply

the net supply current, Isupply, is Iin - Ifb


np

NP,

thanks for the recap, i see what you are trying to say, but i think it is somewhat more complex.

The below screenshot shows the 3 currents:

Isupply grey/white R1
Iin     White R2
Ifb     green

The yellow trace is the voltage across the transistor to show when it turns on and off.

R1 is Isupply and includes the positive cycle Iin and the negative Ifb totaling 7.17mA
R2 is Iin and only has the positive cycle as during the negative Ifb the transistor is off, see yellow trace.
Green is Ifb and can only go left (transistor off) into the supply.

I have overlayed green (and inverted) on R2 to show it is similar as the Isupply waveform R1.

The rms value of Isupply is higher (7.17mA) with the negative cycle, compared to Iin without
the negative cycle (6.5mA), but this is due to how AC rms voltage/current works, it is equivalent to the same
DC value, but it uses both the positive and negative parts to do work (if you can call it that here).


Itsu

[Void]

But i don't think that like Void mentions it is inaccurate.
We are talking about milli-volts and micro-amps deviations, so pretty accurate if you ask me.

Hi Itsu. It's all relative. You have now removed one measurement entry that had wide deviation,
so with that entry removed the measurement deviation seems not so wide now. Looking
at the load LED power measurements, you have one measurement at 10.3 mW and one
measurement at 11.27 mW. That is a variation of about 1mW, or about 9% variation,
so not so small a deviation in measurements. Part of the problem could be due to circuit
instability however, as mentioned previously.

There is no point at all in comparing input and output currents in regards to trying to analyze
efficiency of the circuit. As I have already explained, efficiency of a circuit is determined from the ratio
of average output power to average input power. Comparing currents alone gives no indication whatsoever
on the efficiency of a circuit. I have also explained and demonstrated why looking at RMS readings alone in
circuits of this type with complex AC waveforms will very likely lead a person completely astray.

At any rate, it should be clear already that this circuit configuration gives no indication at all of OU.

[itsu]

Void,

thanks, we get it now.

I have to agree, all the power is almost being accounted for (95%), the rest is very probably consumed like Hoppy mentioned in the potmeter, transformer, cap esr, etc.

Left is now how to correctly interpret the data and the energy flows.


Itsu

[AlienGrey]

Oh yes very nice triangle waveforms of loss, the problem with AC and magnetics is you get loss as your magnetising a transformer
core and then you destroy that magnetic flux by reversing it and doing it again in the other direction!
What you really need to do is recover that energy before it's lost in heat.
If you used only positive or negatively charged pulses that didn't reverse in polarity and ironed out the back 'ringing' in your magnetic drive
the results you obtain might turn out far better, also better magnetic devices might produce better results.