Testing the board

AN2929

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Doc ID 15333 Rev 2

The performance of the VIPER27LN board is much better than required. The power

seem to be disproportionally better than the requirements, it is worth mentioning that often

AC-DC adapter or battery charger manufacturers have very strict requirements concerning

no-load consumption and if the converter is used as an auxiliary power supply, the line filter

of the entire power supply is much bigger and considerably increases the standby

consumption.

performance, in order to give complete information we have provided the input power and

efficiency of the demonstration board in two other low-load cases also. Table 14 and

Table 15 show the performances when the output load is 25 mW and 50 mW respectively.

The input power and the average switching frequency versus the input voltage for different

load conditions are shown in the following figures.

Table 14.

Eff. (%)

(mW)

90

25.760

48

53.22

22.640

2.017

115

26.760

49

54.95

21.940

1.886

230

25.760

61

41.95

35.640

1.461

265

25.760

67

38.74

40.740

1.355

Table 15.

Eff. (%)

90

51.510

80

64.39

28.490

3.407

115

51.510

82

62.82

30.490

3.177

230

51.510

98

52.56

46.490

2.435

265

51.510

104

49.53

52.490

2.284