AN2711

Performance

Doc ID 14425 Rev 3

21/36

6.1.2

Setup for greatest voltage stresses

12 W out, 11 series LEDs, jumpers at W2-W3, W5-W7.

Component stresses

The tap configuration with jumpers at W2-W3 and W5-W7 with 11 series LEDs maximizes

the volts per turn on the transformer. Stress on the bootstrap diode, D9, is too great. A 200 V

diode should be used at that location if the maximum number of LEDs in a string is used for

each jumper configuration.

Figure 14.

96 V input voltage

Figure 15.

132 V input voltage

Table 4.

12 W into 11 series LEDs

Parameter

Very low line

Low line

Nominal line

High line

Line voltage

96

108

120

132

Line current, mA

164.3

143.6

128.9

116.9

Input power, Watts

15.45

15.17

15.05

15.00

Power factor

0.9853

0.9816

0.9745

0.9638

Output voltage

33.39

33.25

33.23

33.20

Output current, mA

371

371

371

371

Current ripple, mA P-P

92

100

96

96

Output power

12.39

12.34

12.33

12.32

Efficiency, %

80.1

81.3

81.9

82.1