BM1C001F Datasheet, PDF (16/35 Pages) Rohm – Power Factor Correction and Quasi-Resonant DC/DC converter IC

BM1C001F
Datasheet
(7) Power Factor Correction (PFC: Power Factor Correction) Part
ç The Power Factor Correction Circuit is a voltage control method with the PFM boundary conduction mode.
The operation circuit is shown is Figure 24 and Timing chart is shown in Figure 25.
Switching Operation
(1) Inductor current (I_L) increases after MOSFET changes to ON.
(2) The slope set by P_RT is compared with V_{P_EO} when MOSFET is turned ON, I_L increases current.
(3) MOSFET is set to be ON after P_IS terminal detects at the zero point.
Figure 24. The Operation Circuit of PFC.
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Figure 25. The Switching Timing Chart.
(7-1) gmAMP
P_VS pin monitors a voltage divided level between resistors of output voltage. P_VS pin has the piled up ripple voltage of AC
frequency (50Hz/60Hz).
The gmAMP filters this ripple voltage and controls the voltage level of P_EO, by responding to error of P_VS pin voltage and
internal reference voltage V_{P_VSAMP} (typ.2.5V (1.625V) ).
Please set cut-off frequency of filter at P_EO pin showed in Figure 26, to about 5~10Hz.
Gm constant is designed 44uA / V.
P_EO
Figure 26. The Block Diagram of gmAMP.
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29.Aug.2013 Rev.002