FAN4810N Fairchild Semiconductor, FAN4810N Datasheet - Page 9

• Manufacturer Part Number: FAN4810N
• Description: IC PFC CTRLR AVERAGE CURR 16DIP
• Manufacturer: Fairchild Semiconductor

Specifications of FAN4810N

• Mode: Average Current
• Current - Startup: 200µA
• Voltage - Supply: 11 V ~ 16.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 16-DIP (0.300", 7.62mm)
• Switching Frequency: 81 KHz
• Maximum Operating Temperature: + 70 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: FAN4810N_NL; FAN4810N_NL

PRODUCT SPECIFICATION
Error Amplifier Compensation
The output of the PFC is typically loaded by a PWM
converter to produce the low voltages and high currents
required at the outputs of a SMPS. PWM loading of the
PFC can be modeled as a negative resistor; an increase in
input voltage to the PWM causes a decrease in the input
current. This response dictates the proper compensation of
the two transconductance error amplifiers. Figure 2 shows
the types of compensation networks most commonly used
for the voltage and current error amplifiers, along with their
respective return points. The current loop compensation is
returned to V
PFC: as the reference voltage comes up from zero volts, it
creates a differentiated voltage on IEAO which prevents the
PFC from immediately demanding a full duty cycle on its
boost converter. There are two major concerns when
compensating the voltage loop error amplifier; stability and
transient response. Optimizing interaction between transient
response and stability requires that the error amplifier’s
open-loop crossover frequency should be 1/2 that of the line
frequency, or 23Hz for a 47Hz line (lowest anticipated
international power frequency). The gain vs. input voltage
of the FAN4810’s voltage error amplifier has a specially
shaped non-linearity such that under steady-state operating
conditions the transconductance of the error amplifier is at a
local minimum. Rapid perturbations in line or load condi-
tions will cause the input to the voltage error amplifier (V
to deviate from its 2.5V (nominal) value. If this happens,
thetransconductance of the voltage error amplifier will
REV. 1.0.12 9/24/03
OUTPUT
Figure 2. Compensation Network Connections for the
PFC
15
2
4
3
I AC
Voltage and Current Error Amplifiers
V FB
V RMS
I SENSE
2.5V
REF
to produce a soft-start characteristic on the
–
+
VEA
VEAO
MODULATOR
GAIN
16
+
–
IEA
IEAO
V REF
1
+
–
FB
)
increase significantly, as shown in the Typical Performance
Characteristics. This raises the gain-bandwidth product of
the voltage loop, resulting in a much more rapid voltage loop
response to such perturbations than would occur with a
conventional linear gain characteristic.
The current amplifier compensation is similar to that of the
voltage error amplifier with the exception of the choice of
crossover frequency. The crossover frequency of the current
amplifier should be at least 10 times that of the voltage
amplifier,to prevent interaction with the voltage loop.
It should also be limited to less than 1/6th that of the
switching frequency, e.g. 16.7kHz for a 100kHz switching
frequency.
There is a modest degree of gain contouring applied to the
transfer characteristic of the current error amplifier, to
increase its speed of response to current-loop perturbations.
However, the boost inductor will usually be the dominant
factor in overall current loop response. Therefore, this
contouring is significantly less marked than that of the
voltage error amplifier. This is illustrated in the Typical
Performance Characteristics.
For more information on compensating the current and
voltage control loops, see Application Note AN42045.
Application Note 42030 also contains valuable information
for the design of this class of PFC.
Figure 3. External Component Connections to V
FAN4810
V BIAS
GND
V CC
R BIAS
CERAMIC
0.22 F
ZENER
15V
FAN4810
CC
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