Test results and significant waveforms

AN4077

12/33

Doc ID 022997 Rev 1

The measured output voltage at different line and static load conditions is reported in the

diagram of

Figure 11 on the right. As can be seen, the voltage is very stable over all the

input voltage and output load range.

4.2

Inductor current in TM and L6564H THD optimizer

In the following figures the waveforms relevant to the inductor current at different voltage

mains are reported: as seen in

Figure 12 and 11, the peak inductor current waveform over a

line half-period follows the MULT (pin #3) at both input mains voltages and therefore the line

current is in phase with the input AC voltage, giving low distortion of the current waveform

and high power factor. On both the drain voltage traces, close to the zero-crossing points of

the sine wave, it is possible to note the action of the THD optimizer embedded in the

L6564H. It is a circuit that minimizes the conduction dead-angle occurring to the AC input

current near the zero-crossings of the line voltage (crossover distortion). In this way, the

Figure 9.

L6564H 100 W TM PFC

demonstration board: efficiency vs

output power

Figure 10.

L6564H 100 W TM PFC

demonstration board: average

efficiency acc. to ES-2

AM11534v1

92.00%

92.50%

93.00%

93.50%

94.00%

94.50%

95.00%

95.50%

96.00%

96.50%

97.00%

97.50%

98.00%

Pout =100W

Pout =75W

Pout =50W

Pout =25W

Output Power

Eff. @100Vac-50Hz

Eff. @115Vac-60Hz

Eff. @230Vac-50Hz

AM11535v1

93.0%

94.0%

95.0%

96.0%

97.0%

Vin_ac [Vrms]

AC input voltage

Av. Eff. @100Vac-50Hz

Av. Eff. @115Vac-60Hz

Av. Eff. @230Vac-50Hz

Figure 11.

output power

AM11536v1

403.0

403.5

404.0

404.5

405.0

405.5

406.0

Pout =100W

Pout =75W

Pout =50W

Pout =25W

Output Power

Vout @100Vac-50Hz

Vout @115Vac-60Hz

Vout @230Vac-50Hz