AN3407

Efficiency measurements

Doc ID 018857 Rev 1

9/25

3

Efficiency measurements

The overall circuit efficiency is measured at different loads, powering the board at the two

nominal input mains voltages. The measures have been done after 30 minutes at load. The

high efficiency of the PFC working in transition mode and the very high efficiency of the

resonant stage working in ZVS provides for an overall efficiency better than 90%.

Figure 8 shows the efficiency at full load over the entire AC input voltage mains range.

Figure 9 shows the power factor (PF) versus load variations.

Table 1.

Load

Vout (V)

Iout (A)

Pout (W)

Pin (W)

PF

Eff (%)

25%

48.67

0.525

25.55

29.30

0.982

87.21

50%

48.67

1.050

51.10

55.87

0.996

91.47

75%

48.67

1.560

75.93

82.01

0.995

92.58

100%

48.67

2.086

101.53

109.28

0.991

92.90

Average eff.

91.04

Table 2.

Load

Vout (V)

Iout (A)

Pout (W)

Pin (W)

PF

Eff (%)

25%

48.67

0.525

25.55

29.45

0.793

86.76

50%

48.67

1.048

51.01

55.59

0.924

91.76

75%

48.67

1.560

75.93

81.06

0.966

93.67

100%

48.67

2.083

101.38

107.46

0.980

94.34

Average eff.

91.63