AN3407 datasheet(13/25 Pages) STMICROELECTRONICS

13 / 25 page

AN3407

Functional check

Doc ID 018857 Rev 1

13/25

Functional check

5.1

PFC circuit

The waveforms measured in the PFC stage have been captured during full load operation at

nominal 115 VAC and 230 VAC in Figure 14 and 15. It can be seen in both figures that the

envelope of the waveform of pin#12 (PFCS) is in phase with that of pin#8 (MULT) and has

same sinusoidal shape, demonstrating the proper functionality of the PFC stage. It is also

possible to measure the peak-to-peak value of the voltage ripple superimposed on the PFC

output voltage due to the low value of the PFC output capacitors. The details of the

waveforms at switching frequency are measured in Figure 16 and 17.

Figure 14.

PFC stage waveforms at 115 VAC -

full load

Figure 15.

PFC stage waveforms at 230 VAC -

full load

Figure 16.

PFC stage waveforms at 115 VAC -

full load - detail

Figure 17.

PFC stage waveforms at 230 VAC -

full load - detail

CH1: MULT

CH4: Vout_PFC

CH2: PFCS

CH1: MULT

CH4: Vout_PFC

CH2: PFCS

CH1: MULT

CH3: Vout_PFC

CH3: Vdrain_Q2

CH1: MULT

CH4: Vout_PFC

CH3: Vdrain_Q2

AN3407 데이터시트(PDF) 13 Page - STMicroelectronics