Test results and significant waveforms

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2.4

Start-up and RUN pin

Figure 26. and Figure 27. detail the waveforms during the start-up of the circuit, at mains

plug-in. The Vcc voltage rises to the turn-on threshold, and the L6563 starts the operation.

For a short time the energy is supplied by the Vcc capacitor, then the auxiliary winding and

the charge pump circuit take over. At the same time, the output voltage rises from peak

value of the rectified mains to the nominal value of the PFC output voltage. The good

margin phase of the compensation network allows a clean start-up, without any large

overshoot that would trigger the Dynamic and Static over voltage protection.

Figure 24.

EVAL6563-400W Input current

Figure 25.

EVAL6563-400W Input current

CH4: Input current

CH4: Input current

Figure 26.

EVAL6563-400W start-up at 90 Vac-

60 Hz - full load

Figure 27.

EVAL6563-400W start-up at 265

Vac-50 Hz - full load

CH1: Output voltage

CH2: Pin #14 - Vcc voltage

CH4: Pin #13 - Gate drive

CH3: Pin #10 - RUN

CH1: Output voltage

CH2: Pin #14 - Vcc voltage

CH4: Pin #13 - Gate drive

CH3: Pin #10 - RUN