Experimental results

AN3032

14/26

Doc ID 16165 Rev 2

4

Experimental results

The schematic of the tested board is shown in Figure 6. The board has been tested for

efficiency, power factor, total harmonic distortion and thermal behavior for the input voltage

range. Table 2 and Table 3 show the results obtained for a 45-minute test.

All the results are very good. Efficiency is approximately 85% and the power factor corrector

is constantly 0.99.

4.1

Start sequence

begins charging. When the voltage at the TCH pin reaches VCHP (4.63 V), the same

capacitor is discharged following an exponential decrease steered by the time constant; this

defines the preheating time.

During this time, the EOI pin is forced to ground and the switching frequency is set by the

oscillator to the preheating value. When the voltage at the TCH pin drops down to

1.53 V, the EOI pin is exponentially charged according to a time constant that defines the

ignition time.

At the same time, the TCH pin goes down to ground. During this phase, the oscillator

generates a reduction of the switching frequency; when the voltage at the EOI pin exceeds

1.9 V, the chip enters run mode.

Table 2.

2 x 58 W T8 board performance

Efficiency(%)

PF

THD(%)

85

126

53.2

84.3

1.487

0.999

3.6

110

123

53.2

85.8

1.13

0.999

6.2

140

122.3

53.2

86.9

0.877

0.997

7.1

185

121.1

53.2

87.8

0.66

0.995

8.7

230

119.9

53.2

88.7

0.528

0.99

11.7

265

118.9

53.2

89.4

0.456

0.985

13

Table 3.

2 x 58 W T8 thermal results of critic system components

Ambient

temp (°C)

Temp

Temp

Temp

Temp

L6585E(°C)

85

25

85

90

99

57

110

25

85

90

87

57

140

25

85

90

81

57

185

25

85

90

75

57

230

25

85

90

64

57

265

25

85

90

56.7

57