PDF《www.onsemi.cn》

390 V)

0 1

2 3

4 5

6 7 0.00% 25.00% 50.00% 75.00% 100.00% time as a percentage of a period (%) Peak, valley and averaged Input Current (A) 峰值电流迹线 Envelop for the peak currents 谷底电流迹线 Envelop for the valley currents Iin(t) IL(tot)

7 高交流线路时的输入电流纹波 Input Current Ripple at High Line ? 输入电压超过输出电压的一半时,谷底电流保持恒定! When Vin exceeds (Vout / 2), the valley current is constant! ? 此电流等于It equates 其中,Rin是PFC输入阻抗 where Rin is the PFC input impedance Peak, averaged and valley current @

230 Vrms,

320 W input (Vout =

390 V) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0.00% 25.00% 50.00% 75.00% 100.00% time as a percentage of a period (%) Peak, valley and averaged Input Current (A) Vin=Vout/2时 无纹波 No ripple when Vin = Vout /

2 2 out in V R ? ? ? ? ? ? ? ? ? ( )

2 ( )

2 2 in avg out out in in rms P V V R V ? = ? ? Iin(t) IL(tot)

8 交流线路输入电流 Line Input Current ? 对于每个支路而言,正弦波的某处波形有如: For each branch, somewhere within the sinusoid: ? 两个平均正弦相位电流之和得到总线电流: The sum of the two averaged, sinusoidal phases currents gives the total line current: ? 假定有极佳的电流平衡: Assuming a perfect current balacing: ? 每个支路的峰值电流就是Iin(t): The peak current in each branch is Iin(t) ( )

1 2

2 sw sw sw in L L T L tot T T I I I I = = +

1 2

2 2 sw sw L L in T T I I I ? = ? = IL1

1 sw L T I

1 2 sw L T I ? IL1

1 sw L T I

1 2 sw L T I ?

9 充电电流的交流分量 Ac Component of the Refueling Current ? 充电电流(输出二极管电流)取决于工作模式 The refueling current (output diode(s) current) depends on the mode: Phase

1 Phase

2 单相CCM Single phase CCM 单相CrM Single phase CrM 交错式CrM Interleaved CrM

2 3 in in out V I V ?

2 3 in in out V I V ? rms value over Tsw rms value over Tsw rms value over Tsw in in out V I V ?

2 in I ? in I in I in I

10 大电容均方根电流降低 A Reduced Rms Current in the Bulk Capacitor ? 正弦电流积分可得到(电阻型负载):Integration over the sinusoid leads to (resistive load): ? 交错式PFC大幅降低均方根电流 Interleaving dramatically reduces the rms currents ? 降低损耗,减少发热量,提升可靠性 reduced losses, lower heating, increased reliability * 频率钳位CrM Frequency Clamped CrM 二极管均方根 电流 Diode(s) rms current (ID(rms)) ID(tot)(rms) = 1.5 A IC(rms) = 1.3 A ID(rms) = 2.2 A IC(rms) = 2.1 A ID(rms) = 1.9 A IC(rms) = 1.7 A 300-W, Vout=390 V Vin(rms)=90 V Capacitor rms current (IC(rms)) 交错式CrM或FCCrM* PFC Interleaved CrM or FCCrM* PFC 单相CrM或FCCrM* PFC Single phase CrM or FCCrM* PFC 单相CCM PFC Single phase CCM PFC

2 2 ( )

32 2

9 out out in rms out out P P V V V η π ? ? ?? ? ? ? ? ? ? ? ? ?

2 2 ( )

16 2

9 out out in rms out out P P V V V η π ? ? ?? ? ? ? ? ? ? ? ? ?

2 2 ( )

8 2

3 out out in rms out out P P V V V η π ? ? ?? ? ? ? ? ? ? ? ? ?

2 ( )

8 2

2 3

3 out in rms out P V V η π ? ? ?? ? ? ? ? ? ?

2 ( )

8 2

2 3

3 out in rms out P V V η π ? ? ?? ? ? ? ? ? ?

2 ( )

8 2

3 out in rms out P V V η π ? ? ?? ? ? ? ? ?

11 交错式PFC小结 Finally… ? 交错式PFC结合了 Interleaved PFC combines: ? 临界导电模式(CrM)工作的优势 The advantages of CrM operations ? 不需要低反向恢复时间(trr)二极管 No need for low trr diode ? 高能效 High efficiency ? 降低输入电流纹波,将大电容中均方根电流减至最小 A reduced input current ripple and a minimized rms current in the bulk capacitor ? 散热更好 A better distribution of heating ? 元器件数量更多,但尺寸 较小 More components but small ones ? 精心调配,适合纤薄外形因数应用,如笔记本适配器和液晶电视 Well adapted to slim form factor applications such as notebook adapters and LCD TVs ? 更多信息参见安森美半导体应用笔记AND8355 Refer to application note AND8355 for more details