AN3329 datasheet(10/47 Pages) STMICROELECTRONICS

10 / 47 page

Efficiency measurement

AN3329

10/47

Doc ID 18376 Rev 1

The average efficiency has been calculated according to ENERGY STAR 2.0 criteria.

Results are summarized in Figure 3 and 4.

Standby supply efficiency

Standby supply efficiency has been measured and the results are plotted in Figure 5. As

shown, the efficiency during rated load operation is above 82 %, over the whole input mains

voltage range, from 50 % to full load.

Efficiency during standby operation at very light load, like microprocessor and wake-up

circuitry, is plotted in Figure 6. As shown, in this condition it is higher than 35 % at 230 Vac,

therefore, it allows to supply the microprocessor with a significant low consumption from the

mains. It should be mentioned that the standby supply efficiency has been calculated

measuring the input power at the input connector, including power loss contribution due to

all residual loads connected to mains before and after the input bridge rectifier, like the EMI

filter and PFC resistor dividers.

Figure 3.

Overall efficiency vs. output power Figure 4.

Average efficiency acc. ES-2

Figure 5.

Standby supply efficiency vs.

output power

Figure 6.

Standby supply efficiency vs. light

load output power

AN3329 Datasheet(PDF) 10 Page - STMicroelectronics