03-11-6 52 OC 15mA 4-32V DC 5.2.5 PFC (PF) S PF = P / S= V* I1 *COS / V* IR = I 1 * COS / IR = COS 5-4 I1 IR COS IR I1 R=1 5-25 100%-130% I1 IR 0.6 0.7 5-24 figure 5-24 SSR controlling principle 5-25 figure 5-25 capacitor charge current waveform 03-11-6 53 5-26 L VT VD C RS RS C MOSFET MOSFET L Il Il MOSFET Vd C 5-26 figure 5-26 PFC circuit 03-11-6 54 il Il 0 MOSFET 1 UC3854 UC3854 UC3854 PWM UC3854 MOSFET 7.5 UC3854 LC PFC I R / = / 2 * 2 =0.9 Lon PF 5-27 5-27 PF FIGURE 5-27 the relationship between PF and inductance in a PFC circuit 03-11-6 55 5-27 =0.03 0.94 0.79 L 0.9
