NCP1611ADR2G ONSEMI [ON Semiconductor], NCP1611ADR2G Datasheet - Page 17

• Manufacturer Part Number: NCP1611ADR2G
• Description: Enhanced, High-Efficiency Power Factor Controller
• Manufacturer: ONSEMI [ON Semiconductor]

Introduction
your PFC stage throughout the load range. In addition, it
incorporates protection features for rugged operation. More
generally, the NCP1611 is ideal in systems where
cost−effectiveness, reliability, low stand−by power and high
efficiency are key requirements:
•
•
•
The NCP1611 is designed to optimize the efficiency of
Current Controlled Frequency Fold−back: the NCP1611
is designed to drive PFC boost stages in so−called
Current Controlled Frequency Fold−back (CCFF). In
this mode, the circuit classically operates in Critical
conduction Mode (CrM) when the inductor current
exceeds a programmable value. When the current is
below this preset level, the NCP1611 linearly reduces
the frequency down to about 20 kHz when the current
is zero. CCFF maximizes the efficiency at both nominal
and light load. In particular, stand−by losses are
reduced to a minimum. Similarly to FCCrM controllers,
an internal circuitry allows near−unity power factor
even when the switching frequency is reduced.
Skip Mode: to further optimize the efficiency, the
circuit skips cycles near the line zero crossing when the
current is very low. This is to avoid circuit operation
when the power transfer is particularly inefficient at the
cost of current distortion. When superior power factor
is required, this function can be inhibited by offsetting
the “FFcontrol” pin by 0.75 V.
Low Start−up Current and large V
The start−up consumption of the circuit is minimized to
allow the use of high−impedance start−up resistors to
pre−charge the V
of the UVLO hysteresis is 6 V to avoid the need for
large V
30
28
26
24
22
20
−50
CC
−30
Figure 57. Blanking Time for Line Range
capacitors and help shorten the start−up time
T
−10
J
, JUNCTION TEMPERATURE (°C)
Detection vs. Temperature
CC
capacitor. Also, the minimum value
10
30
50
CC
DETAILED OPERATING DESCRIPTION
range (B version):
70
TYPICAL CHARACTERISTICS
90
110
http://onsemi.com
130
17
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without the need for too dissipative start−up elements.
The A version is preferred in applications where the
circuit is fed by an external power source (from an
auxiliary power supply or from a downstream
converter). Its maximum start−up level (11.25 V) is set
low enough so that the circuit can be powered from a
12−V rail. After start−up, the high V
rating allows a large operating range from 9.5 V up to
35 V.
Fast Line / Load Transient Compensation (Dynamic
Response Enhancer): since PFC stages exhibit low loop
bandwidth, abrupt changes in the load or input voltage
(e.g. at start−up) may cause excessive over or
under−shoot. This circuit limits possible deviations
from the regulation level as follows:
Safety Protections: the NCP1611 permanently monitors
the input and output voltages, the MOSFET current and
the die temperature to protect the system from possible
over−stress making the PFC stage extremely robust and
reliable. In addition to the OVP protection, these
methods of protection are provided:
−1
−2
−3
−4
− The NCP1611 linearly decays the power delivery to
− The NCP1611 dramatically speeds−up the regulation
8
7
6
5
4
3
2
1
0
−50
zero when the output voltage exceeds 105% of its
desired level (soft OVP). If this soft OVP is too
smooth and the output continues to rise, the circuit
immediately interrupts the power delivery when the
output voltage is 107% above its desired level.
loop when the output voltage goes below 95.5% of
its regulation level. This function is enabled only
after the PFC stage has started−up to allow normal
soft−start operation to occur.
−30
Figure 58. Brown−Out Pin Bias Current,
(V
−10
T
SENSE
J
, JUNCTION TEMPERATURE (°C)
10
= V
BOH
30
) vs. Temperature
50
70
CC
maximum
90
110
130