STMicroelectronics L6563H 100 W TM PFC demonstration board EVL6563H-100W EVL6563H-100W Fiche De Données

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Doc ID 16261 Rev 3

In 

 and 

 the detail of the waveforms at switching frequency shows the operation 

of transition-mode control. Once the inductor has transferred all the stored energy, a falling 
edge on the ZCD pin (pin #13) is detected and it will trigger a new on-time by setting the 
gate drive high. As soon as the current signal on the CS pin (pin #4) reaches the level 
programmed by the internal multiplier circuitry according to the input mains instantaneous 
voltage and the error amplifier output level, the gate drive is set low and MOSFET 
conduction is stopped. A following off-time will transfer the energy stored in the inductor into 
the output capacitor and to the load. At the end of the current conduction a new 
demagnetization will be detected by the ZCD that will provide for a new on-time of the 
MOSFET.

         

CH4: Q1 drain voltage

CH2: MULT voltage - pin #3 

CH1:  L2 inductor current

         

CH4: Q1 drain voltage

CH2: MULT voltage - pin #3 

CH1:  L2 inductor current