ncp1601a ON Semiconductor, ncp1601a Datasheet - Page 16

• Manufacturer Part Number: ncp1601a
• Description: Compact Fixed Frequency Discontinuous Or Critical Conduction Voltage Mode Power Factor Correction Controller
• Manufacturer: ON Semiconductor

Appendix I – Summary of Equations in NCP1601 Boost PFC
Boost converter
Input current averaged by
filter capacitor
Voltage for on time V
MOSFET on−time t
Switching period
Minimum Inductor for
CRM
Input impedance
Input power
Output power
Maximum input power
when V
Minimum ramp capacitor
when V
Control voltage V
Description
control
control
= 1 V
= 1 V
control
1
ton
³
³
C ramp u
³
P in_max +
t 1 ) t 2 +
t 1 ) t 2 +
P in +
V out
V ton + V control
t 1 +
L u L (CRM) +
Z in +
V ctrl +
P out + hP in +
I in +
V in
t
V
1
V out * V in
+
control
LI pk
V in
is constant for unity PFC
I pk
V ac 2 C ramp V control
C ramp V control
2
C ramp V ac 2
t 1 ) t 2
V out
2LI ch P in
, or
V ac 2
V out * V in
V out * V in
t 2
is constant for unity PFC
P in
2LI ch
Critical Mode (CRM)
V ac 2 C ramp
V out
V out
2LI ch
2LI ch
@ 2LI ch
t 1 +
V out * V in
h V ac 2 C ramp V control
+
V out
t 1 ) t 2
NCP1601A, NCP1601B
C ramp V control
C ramp V control
LI pk
t 1
V in
2LI ch
http://onsemi.com
I ch
V in
I pk
I ch
1
f
16
, or
³
³
t 1 +
³
V ton +
t 1 ) t 2 +
t 1 ) t 2 +
I in +
Same as CRM
Same as CRM
Same as CRM
Same as CRM
Same as CRM
Same as CRM
Same as CRM
V out
V in
t
V
1
V out * V in
LI pk
control
V in
+
t 1 ) t 2
(t
1
t 1 ) t 2
V out
t 1 ) t 2
+ t
T
, or
t 1
T
is constant for unity PFC
T
2
t 2
) is constant for unity PFC
C ramp V control
Discontinuous Mode (DCM)
V out * V in
I pk
2
t 1 +
V control
V out
+
I ch
t 1 ) t 2
t 1
V out * V in
T
C ramp V control
V out
, or
I ch
T
C ramp V control
I ch