AN3142

List of figures

Doc ID 17005 Rev 3

3/44

List of figures

Figure 1.

Line, inductor, switch and diode currents in FF-CCM PFC. . . . . . . . . . . . . . . . . . . . . . . . . . 1

Figure 2.

Line, inductor, switch and diode currents in TM PFC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Figure 3.

Basic waveforms for fixed frequency PWM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Figure 4.

Basic waveforms for fixed-off-time PWM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Figure 5.

Block diagram of an FOT-controlled PFC pre-regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Figure 6.

Circuit implementing FOT control with the L6563S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 7.

ZCD pin signal with the fixed off-time generator circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Figure 8.

Switching frequency fixing the line voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 9.

The effect of fixing off-time - boundary between DCM and CCM . . . . . . . . . . . . . . . . . . . . 16

Figure 10.

Conduction losses and total losses in the STP12NM50FP MOSFET couples for the 400W

FOT PFC

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Figure 11.

L6563S internal schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 12.

Open-loop transfer function-bode plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figure 13.

Phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figure 14.

Multiplier characteristics family for VFF =1 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 15.

Multiplier characteristics family for VFF=3 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 16.

Mains detector and discharge resistor allow fast response to sudden line drops not depend-

ing on the external RC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Figure 17.

Brownout function in L6563S and L6563H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figure 18.

Switching frequency function on the peak of the sinusoid input voltage waveform and the cor-

responding off-time value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Figure 19.

Off-time vs. input mains voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 20.

Switching frequency vs. input mains voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 21.

L6563H and L6563S pin-out comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Figure 22.

High-voltage startup generator: internal schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Figure 23.

Timing diagram: normal power-up and power-down sequences . . . . . . . . . . . . . . . . . . . . 35

Figure 24.

High-voltage startup behavior during latch-off protection . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 25.

High-voltage startup managing the DC-DC output short circuit . . . . . . . . . . . . . . . . . . . . . 37

Figure 26.

Excel spreadsheet design specification input table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Figure 27.

Other design data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Figure 28.

Excel spreadsheet FOT PFC using the L6563S (SO14-black pin out) schematic . . . . . . . 39

Figure 29.

Excel spreadsheet FOT PFC using the L6563H (SO16-red pin out) schematic. . . . . . . . . 39

Figure 30.

Excel spreadsheet BOM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Figure 31.

L6563S 400W FOT PFC demonstration board (p/n EVL6563S-400W) . . . . . . . . . . . . . . . 41