 |
Zakładka z wyszukiwarką danych komponentów |
|
|
Zakładka z wyszukiwarką danych komponentów |
|
FAN9611 Arkusz danych(PDF) 10 Page - Fairchild Semiconductor |
|
||||||||||||||||||||||||||||||
FAN9611 Arkusz danych(HTML) 10 Page - Fairchild Semiconductor |
|
|
10 / 18 page  AN-6086 © 2009 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.4 • 4/22/10 10 , (1 cos(4 )) DAVG OUT LINE I If t π =− ⋅ ⋅ OUT I , 2 OUT OUT RIPPLE LINE OUT I V fC π = OUT V D I , D AVG I Figure 16. Output Voltage Ripple (Design Example) With the ripple specification of 8Vp-p, the capacitor should be: , 1 398 22 50 8 OUT OUT LINE OUT RIPPLE I CF fV μ ππ >= = ⋅⋅ ⋅ ⋅ Since minimum allowable output voltage during one cycle line (20ms) drop-outs is 330V, the capacitor should be: 3 22 2 2 , 2 2 400 20 10 313 400 330 OUT HOLD OUT OUT OUT MIN Pt CF VV μ − ⋅ ⋅⋅ × >= = −− Thus, two 220 μF capacitors in parallel are selected for the output capacitor. [STEP-9] Design Compensation Network The boost PFC power stage can be modeled as shown in Figure 17. Since FAN9611/12 employs line feed-forward, the power stage transfer function becomes independent of the line voltage. Then, the power stage can be modeled as a voltage-controlled current source supplying RC network. Figure 17. Small Signal Modeling of the Power Stage By averaging the diode current during the half line cycle, the low frequency behavior of the voltage controlled current source of Figure 17 is obtained as: , (0.2) 4.1 COMP D LF OUT MAX V II K − =⋅ ⋅ (27) where IOUT is total nominal output current corresponding to POUT, VCOMP is compensation pin voltage, 0.2V is PWM offset voltage and 4.1 is error amplifier control range (refer to Figure 13). Then, the low-frequency, small-signal, control-to-output transfer function is obtained as: ˆ 1 ˆ 4.1 2 1 2 OUT OUT MAX L COMP P vI K R s v f π ⋅ =⋅ ⋅ + (28) where 2 2 P LOUT f RC π = ⋅ and RL is the output load resistance in a given load condition. Figure 18 shows the variation of the control-to-output transfer function for different loads. As can be seen, the characteristics at frequencies above the pole are unchanged while the pole moves as load changes. Since the low frequency gain increases as load decreases, the light load condition is the worst condition for feedback loop compensation. Assuming the load resistance is infinite, the control-to-output transfer function at light load condition is obtained from Equation 28 as: @, ˆ 1 | ˆ 4.1 OUT OUT MAX LIGHT LOAD COMP OUT vI K vsC ⋅ ≅⋅ (29) |
Podobny numer części - FAN9611 |
|
Podobny opis - FAN9611 |
|
|
|
Link URL |
| Polityka prywatności |
| ALLDATASHEET.PL |
| Czy Alldatasheet okazała się pomocna? [ DONATE ] |
O Alldatasheet | Reklama | Kontakt | Polityka prywatności | Linki | Lista producentów All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
Polish ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
