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參數資料
| 型號： | FAN4810 |
| 廠商： | Fairchild Semiconductor Corporation |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | Power Factor Correction Controller |
| 中文描述： | 功率因數校正控制器 |
| 文件頁數： | 8/14頁 |
| 文件大?。?/td> | 160K |
| 代理商： | FAN4810 |
FAN4810
PRODUCT SPECIFICATION
8
REV. 1.0.12 9/24/03
Current Error Amplifier
The current error amplifier’s output controls the PFC duty
cycle to keep the average current through the boost inductor
a linear function of the line voltage. At the inverting input to
the current error amplifier, the output current of the gain
modulator is summed with a current which results from a
negative voltage being impressed upon the I
SENSE
pin. The
negative voltage on I
SENSE
represents the sum of all currents
flowing in the PFC circuit, and is typically derived from a
current sense resistor in series with the negative terminal of
the input bridge rectifier. In higher power applications, two
current transformers are sometimes used, one to monitor the
ID of the boost MOSFET(s) and one to monitor the I
F
of the
boost diode. As stated above, the inverting input of the
current error amplifier is a virtual ground. Given this fact,
and the arrangement of the duty cycle modulator polarities
internal to the PFC, an increase in positive current from the
gain modulator will cause the output stage to increase its
duty cycle until the voltage on I
SENSE
is adequately negative
to cancel this increased current. Similarly, if the gain
modulator’s output decreases, the output duty cycle will
decrease, to achieve a less negative voltage on the I
SENSE
pin.
Cycle-By-Cycle Current Limiter
The I
SENSE
pin, as well as being a part of the current feed-
back loop, is a direct input to the cycle-by-cycle current
limiter for the PFC section. Should the input voltage at this
pin ever be more negative than -1V, the output of the PFC
will be disabled until the protection flip-flop is reset by the
clock pulse at the start of the next PFC power cycle.
TriFault Detect
TM
To improve power supply reliability, reduce system
component count, and simplify compliance to UL 1950
safety standards, the FAN4810 includes TriFault Detect.
This feature monitors VFB (Pin 15) for certain PFC fault
conditions.
In the case of a feedback path failure, the output of the PFC
could go out of safe operating limits. With such a failure,
VFB will go outside of its normal operating area. Should
VFB go too low, too high, or open, TriFault Detect senses the
error and terminates the PFC output drive.
TriFault detect is an entirely internal circuit. It requires no
external components to serve its protective function.
Overvoltage Protection
The OVP comparator serves to protect the power circuit
from being subjected to excessive voltages if the load should
suddenly change. A resistor divider from the high voltage
DC output of the PFC is fed to V
FB
. When the voltage on
V
FB
exceeds 2.75V, the PFC output driver is shut down.
The OVP comparator has 250mV of hysteresis, and the PFC
will not restart until the voltage at V
FB
drops below 2.50V.
The V
FB
should be set at a level where the active and passive
external power components and the FAN4810 are within
their safe operating voltages, but not so low as to interfere
with the boost voltage regulation loop.
Figure 1. PFC Block Diagram
15
VEAO
IEAO
VFB
IAC
VRMS
ISENSE
RAMP 1
OSCILLATOR
OVP
+
PFC ILIMIT
TRI-FAULT
2.5V
–
–
+
16
2
4
3
VEA
7
+
–
IEA
1
+
–
+
–
PFC OUT
12
S
R
Q
Q
S
R
Q
Q
2.75V
–
1V
+
–
0.5V
1.6k
1.6k
GAIN
MODULATOR
相關PDF資料 |
PDF描述 |
|---|---|
| FAN4810M | Power Factor Correction Controller |
| FAN4810MX | Power Factor Correction Controller |
| FAN4810N | Terminal Block RoHS Compliant: Yes |
| FAN4822 | ZVS Average Current PFC Controller |
| FAN4822IM | Analog IC |
相關代理商/技術參數 |
參數描述 |
|---|---|
| FAN4810EVAL | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Power Factor Controller |
| FAN4810M | 功能描述:功率因數校正 IC PFC Preregulator RoHS:否 制造商:Fairchild Semiconductor 開關頻率:300 KHz 最大功率耗散: 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel |
| FAN4810M_Q | 功能描述:功率因數校正 IC PFC Preregulator RoHS:否 制造商:Fairchild Semiconductor 開關頻率:300 KHz 最大功率耗散: 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel |
| FAN4810MX | 功能描述:功率因數校正 IC PFC Preregulator RoHS:否 制造商:Fairchild Semiconductor 開關頻率:300 KHz 最大功率耗散: 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel |
| FAN4810N | 功能描述:功率因數校正 IC PFC Preregulator RoHS:否 制造商:Fairchild Semiconductor 開關頻率:300 KHz 最大功率耗散: 最大工作溫度:+ 125 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Reel |
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