AN2929 datasheet(17/32 Pages) STMICROELECTRONICS

17 / 32 page

AN2929

Testing the board

Doc ID 15333 Rev 2

17/32

Figure 17.

ENERGY STAR® efficiency criteria

Figure 17 shows the efficiency criteria 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

logarithmic scale.

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

to be compliant with ENERGY STAR® requirements, needs to have efficiency higher than

74.7%. For all the considered input voltages, the efficiency results (see Table 8) are higher

than the recommended value.

2.4

Light-load performance

The input power of the converter was measured in no load condition, with brownout

protection disabled (see Section 2.8) for different input voltages and the results are given in

Table 12.

In version 2.0 of the ENERGY STAR® program the power consumption of the power supply

when it is not loaded is also considered. The criteria for compliance are given in the table

below.

Table 12.

No-load input power (no brownout)

VINAC (VRMS)Pin (mW)

fSW_AVG (kHz)

0.590

115

0.558

230

0.434

265

0.401

Table 13.

Energy consumption criteria for no load

Nameplate output power (Pno)

Maximum power in no load for AC-DC EPS

0 W < Pno ≤ 50 W

< 0.3 W

50 W < Pno < 250 W

< 0.5 W

AN2929 Datasheet(PDF) 17 Page - STMicroelectronics