I'm making an AC to DC power supply that connects to mains. There's an AC to DC converter, buck converter and a smoothing LDO that outputs a DC controlled with pots.
I'm verifying the supply, and have been trying to get efficiency measurements. Due to limited equipment, I can only measure input Vrms, input Irms, output DC voltage, and output DC current. However, if I just do the Vdc * Idc/(Vrms * Irms) calculation, my effeciency goes above 100% at the higher loads, which is obviosuly wrong.
I know there's apparent vs real power when driving reactive loads with AC, but when I'm measuring the Vrms and Irms that goes into my circuit, that is the real power, is it not? Adding a power factor would mean my circuit becomes even more unphysically efficient.
Is there anything else that I haven't taken into account?