NCP1650 ON, NCP1650 Datasheet - Page 23

• Manufacturer Part Number: NCP1650
• Description: Power Factor Controller
• Manufacturer: ON

Basic Specifications
of specifications. As a minimum, the following parameters
should be known before beginning:
Po
Vrms
Vrms
f
V
requirements. The output voltage may not be defined. In
general, it should be slightly greater than the peak of the line
waveform at high line. For a 265 v
switch
V
out
Note: This is a theoretical design, and it is not implied that a circuit designed by this procedure will operate properly without normal
troubleshooting and adjustments as are common with any power conversion circuit. ON Semiconductor provides a spread sheet that
incorporates the following equations, and will calculate the bias components for a circuit using the above schematic.
in
The design of any power converter begins with a basic set
Most of these parameters will be dictated by system
max
D
D
D
D
min
max
1
2
3
4
(Maximum rated output power)
(Minimum operational line voltage)
(Maximum operational line voltage)
(Nominal switching frequency)
(Nominal regulated output voltage)
R
R
C
R
C
8
ac2
8
ac1
ac
R
C
C
R
LOOP COMP
9
in
7
7
AC INPUT
AC COMP
C
AC REF
4
P
FB/SD
COMP
P
C
GND
C
max
R
9
3
3
15
7
6
8
9
5
4
3
4.24 V
3.68 V
AVERAGE CURRENT
4 V
COMPENSATION
+
−
+
−
+
−
ERROR
+
−
a
p
a
p
REFERENCE
MULTIPLIER
MULTIPLIER
AMP
25 k
POWER
rms
input, the peak line
Figure 40. Typical Application Schematic
4.5 V
VOLTAGE/POWER
ORing NETWORK
20 k
60 k
2.5 V
AC ERROR AMP
RAMP
COMP
DESIGN GUIDELINES
POWER
+
−
+
−
13
http://onsemi.com
AMP
0.75 V
k I
R
in
13
NCP1650
= V
line
1.08 V
COMPENSATION
ref
0.85 V
+
OSCILLATOR
23
REFERENCE
V
CC
14
BUFFER
RAMP
ref
16 k
V−I
voltage would be 375 volts, and 400 volts is a standard
output voltage. In no case should it be less than the peak
input line voltage.
Inductor
converter, there is no magic formula to determine the
optimum value of the inductor. There are several trade−off’s
that should be considered. These include peak current vs.
average current, and switching losses vs. core losses. All of
these are a function of inductance, line and load. These
parameters determine when the converter is operating in the
continuous conduction mode and when it is operating in the
discontinuous conduction mode.
4 V
AC
−
+
C
C
1
T
T
For an average current mode, fixed frequency PFC
OVERVOLTAGE
SHUTDOWN
COMPARATOR
REFERENCE
REGULATOR
−
+
4 V
−
+
PWM
UVLO
4 V
S
S
R
R
I
avg
10
AMPLIFIER
CURRENT
SENSE
Q
10 11
I
+
−
avg fltr
6.5 V
C
DRIVER
11
OUT
16
12
2
V
I
S−
ref
(OPTIONAL)
LIMITER
INRUSH
Q1
R
D
0.1 mF
C
shunt
C
5
out
L
ref
1
R
R
to FB
DC1
DC2