ncp1653 ON Semiconductor, ncp1653 Datasheet - Page 14

• Manufacturer Part Number: ncp1653
• Description: Compact Fixed-frequency Current-mode Power Factor Correction Controller
• Manufacturer: ON Semiconductor

C
calculation to always be the peak of the sinusoidal voltage
due to very little current consumption (i.e., V
I
V
PFC duty modulation.
Hence, the value of R
938 kW for possibly up to 400 V instantaneous input voltage.
Overpower Limitation (OPL)
hence represents the input current approximately.
Input−voltage current I
voltage V
product (I
(I
level 3 nA
to 0 V. It makes V
pulled to be its maximum. It generates the minimum duty
ratio or no duty ratio eventually so that the input power is
vac
ac
vac
L
There is an internal 9 V ESD Zener Diode on the pin.
Sense current I
When the product (I
Figure 38. Overpower Limitation Reduces V
× V
and will be used in overpower limitation (OPL) and the
≈ 0). This I
V
is to maintain the In pin (Pin 3) voltage in the
reg
Regulation Block
96% I
ac
).
ac
S
2
, the output V
× I
C vac
Figure 37. Input Voltage Sensing
R vac
ref
and hence represents the input voltage. Their
vac
vac
V in
I
400 V * 9 V
) represents an approximated input power
ref
S
current represents the RMS input voltage
represents the inductor current I
control
R vac
I
R vac u 938 kW
FB
S
vac
I vac
× I
reg
vac
to be 0 V indirectly and V
vac
is recommended to be at least
0
Overpower
of the regulation block is pulled
Limitation
) is greater than a permissible
represents the RMS input
u
In
1
3
9 V * 4 V
300 k
12 kW
9 V
12 k
Current
Mirror
in
2
= √2 V
NCP1653, NCP1653A
V control
4 V
control
(eq.19)
http://onsemi.com
ac
L
M
and
and
is
14
limited. The OPL is automatically deactivated when the
product (I
3 nA
(I
(eq.20).
Biasing the Controller
decoupling capacitor next to the V
When the NCP1653 operates in follower boost mode, the PFC
output voltage is not always regulated at a particular level
under all application range of input voltage and load power.
It is not recommended to make a low−voltage bias supply
voltage by adding an auxiliary winding on the PFC boost
inductor. Alternatively, it is recommended to get the V
biasing supply from the second−stage power conversion stage
as shown in Figure 39.
mode, it is possible to make a low−voltage bias supply by
adding an auxiliary winding on the PFC boost inductor in
Figure 40. In PFC boost circuit, the input is the rectified AC
voltage and it is non−constant versus time that makes the
auxiliary winding voltage also non−constant. Hence, the
configuration in Figure 40 charges the voltages in
capacitors C1 and C2 to n×(V
the turn ratio. As a result, the stack of the voltages is n×V
that is constant and can be used as a biasing voltage.
AC
Input
L
It is recommended to add a typical 1 nF to 100 nF
When the NCP1653 operates in constant output voltage
× V
Figure 39. Recommended Biasing Scheme in
2
Filter
I L @
EMI
level corresponds to the approximated input power
ac
) to be smaller than the particular expression in
I L @ V ac t
S
R CS
× I
R S
vac
) becomes lower than the 3 nA
Follower Boost Mode
R CS
I S I vac t 3 nA 2
V ac @
R S
NCP1653
R vac ) 12 kW
R vac ) 12 kW
out
CC
2
− V
2
pin for proper operation.
in
) and n×V
V
cc
3 nA 2
Power Converter
Second−stage
V
t 3 nA 2
bulk
2
level. This
in
and n is
(eq.20)
Voltage
Output
CC
out