efficiency measurement of AC powered system: HOW?

[gilbertomaldito]

I have LED driver powered from AC source... I would like to know how to measure EFFiCIENCY of this circuit? Is this right:
Eff = Pave load / Pave ACsupply?
-my load is LED
-my Vac=110V 60Hz
-I just tried to get the Power ave of my load and my AC source. and divide them.

I get an eff of 20% .. I feel there is something wrong with my meausrement.
I am expecting to get more than 80%.

If you have a system like the LM3445 how to measure this efficiency. (**broken link removed**) - 1st page, you can see the system and efficiency graph on the lower right of the same page.

As you can see there is AC source then Bridge Rec and then the Buck regulator with LED as a LOAD.

 

[FvM]

I just tried to get the Power ave of my load and my AC source. and divide them. get an eff of 20%.. I feel there is something wrong with my meausrement.

Yes, most likely. How did you measure the input and output power? For the AC input, you have to measure real power, not apparent power.
Do you have an instrument that can measure it directly or did you calculate it from voltage and current. In the latter case, you have to
consider the power factor.

 

[gilbertomaldito]

Yes, most likely. How did you measure the input and output power?
For the AC input, you have to measure real power, not apparent power.
Do you have an instrument that can measure it directly or did you calculate it from voltage and current. In the latter case, you have to
consider the power factor.

I measured it using HSPICE: I simply used Pi = AVG P(Vac) and Po = I RMS(LED) x V RMS(LEDS) and then Po/Pi. my eff is 20% ...I am expecting eff>80%

What do you mean consider PF? U mean my PF will be my Eff?
But PF = Real/Apparent (which are both measured in the input)