AN3011 datasheet(17/37 Pages) STMICROELECTRONICS

17 / 37 page

AN3011

Efficiency

Doc ID 16043 Rev 1

17/37

low voltage power supply, must have a nameplate output voltage lower than 6 V and a

nameplate output current greater than or equal to 550 mA.

Table 8

and 9 show the EPA energy efficiency criteria for AC/DC power supplies in active

mode for standard models and for low voltage models respectively.

Figure 19.

ENERGY STAR efficiency criteria

The criteria are plotted in Figure 19 above where the red line is the criteria for the standard

model and the blue line is the criteria for the low voltage model. The PNO axe is in the

logarithmic scale.

The presented power supply belongs to the low voltage power supply category and, in order

to be compliant with ENERGY STAR requirements, must have an efficiency higher than 74.1

% when the converter input voltage is at the nominal value (115 VAC or 230 VAC in this

case). For all the considered input voltages the efficiency (see Table 6) results are higher

than the required value.

Table 8.

Energy efficiency criteria for standard models

Nameplate output power (Pno)

Minimum average efficiency in active mode (expressed as

a decimal)

0 to = 1 W

= 0.48 *Pno+0.140

> 1 to = 49 W

= [0.0626 * In (Pno)] + 0.622

> 49 W

= 0.870

Table 9.

Energy efficiency criteria for low voltage models

Nameplate output power (Pno)

Minimum average efficiency in active mode (expressed as

a decimal)

0 to = 1 W

= 0.497 *Pno+0.067

> 1 to = 49 W

= [0.075 * In (Pno)] + 0.561

> 49 W

= 0.860

AN3011 Datasheet(PDF) 17 Page - STMicroelectronics