AN3118

Test results and significant waveforms

Doc ID 16847 Rev 2

21/31

The event of an open-loop is shown in Figure 32 and 33; notice the protection intervention

latching the operation of the L6563H. In order to keep the L6563H latched after the open-

loop detection, in Figure 33 it is possible to note the activation of the HVS circuit, it’s

necessary to keep the L6563H correctly supplied, sustaining the Vcc value above the

the input power. The connection of the HVS pin after the rectifier bridge allows a faster

restart in the case of latch than connecting the pin to the bulk capacitor. In that case, in fact,

to restart the operation it is necessary to wait the time needed by the HVS to discharge the

Figure 31.

EVL6563H-250W load transient at 115 Vac - 60 Hz - full load to no-load

CH1: PFC output voltage,

CH2: PFC_OK (pin #7),

CH3: gate drive (pin #15),

CH4: Iout

Figure 32.

EVL6563H-250W TM PFC: open=-

loop at 115 Vac - 60 Hz - full load

Figure 33.

EVL6563H-250W TM PFC: open-

loop at 115 Vac - 60 Hz - full load -

long acquisition

CH1: PFC output voltage, CH2: Vcc (pin #16)

CH3: gate drive (pin #15)

CH4: PWM_LATCH (pin#8)

CH1: PFC output voltage, CH2: Vcc (pin #16)

CH3: gate drive (pin #15)

CH4: PWM_LATCH (pin#8)