AN2929

Testing the board

Doc ID 15333 Rev 2

25/32

Figure 26.

OVP

The test was performed in different line and load conditions, to check the dependence of the

output voltage value, when the protection is activated, on the converter’s input voltage and

load.

The results are shown in Table 17.

The variation with load and line condition is very low ([5.45 V; 5.59 V],

ΔV

a turn ratio between the secondary and auxiliary windings that has a precision of 5%, it is

possible to fix the output overvoltage 20%, 25% higher than the nameplate output voltage of

the converter, without risk of undesired protection tripping due to the spread in the values of

the components (R3 and R14), of the transformer parameter (turn ratio) and of the

It is possible to not implement this protection if it is not necessary, by not mounting diode D2

and resistor R14, thus reducing the number of components.

Table 17.

Input and output load

Load

No load

25% (0.6 A)

50% (1.2 A)

75% (1.8 A)

100% (2.4 A)

90

5.56

5.50

5.46

5.45

5.45

115

5.56

5.51

5.49

5.48

5.46

230

5.59

5.55

5.52

5.53

5.53

265

5.59

5.54

5.54

5.53

5.53

Working condition:

No load

Feedback pin: discon-

nected.