- 您現在的位置：買賣IC網 > Datasheet目錄38 > FAN6921MLMY (Fairchild Semiconductor)IC CTLR PFC/FLYBACK 16-SOICN Datasheet資料下載
參數資料
| 型號： | FAN6921MLMY |
| 廠商： | Fairchild Semiconductor |
| 文件頁數： | 15/23頁 |
| 文件大小： | 1764K |
| 描述： | IC CTLR PFC/FLYBACK 16-SOICN |
| 標準包裝： | 2,500 |
| 模式： | 臨界傳導（CRM） |
| 電流 - 啟動： | 10µA |
| 電源電壓： | 8.5 V ~ 25 V |
| 工作溫度： | -40°C ~ 105°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 16-SOIC（0.154"，3.90mm 寬） |
| 供應商設備封裝： | 16-SOIC N |
| 包裝： | 帶卷 (TR) |
?2010 Fairchild Semiconductor Corporation
www.fairchildsemi.com
FAN6921ML " Rev. 1.0.3
15
Functional Description
PFC Stage
Multi-Vector Error Amplifier and THD Optimizer
For better dynamic performance, faster transient
response, and precise clamping on PFC output,
FAN6921ML uses a transconductance type amplifier
with proprietary innovative multi-vector error amplifier.
The schematic diagram of this amplifier is shown in
Figure 25. The PFC output voltage is detected from the
INV pin by an external resistor divider circuit that
consists of R
1
and R
2
. When PFC output variation
voltage reaches 6% over or under the reference voltage
of 2.5 V, the multi-vector error amplifier adjusts its output
sink or source current to increase the loop response to
simplify the compensated circuit.
C
CO M P
3
2
F A N 6 9 2 1
C o
I N V
2 . 5 V
2 . 3 5 V
2 . 6 5 V
E r r o r
A m p lif ie r
P F C
V o
C O M P
R
1
R
2
Figure 25. Multi-Vector Error Amplifier
The feedback voltage signal on the INV pin is compared
with reference voltage 2.5 V, which makes the error
amplifier source or sink current to charge or discharge
its output capacitor C
COMP
. The COMP voltage is
compared with the internally generated sawtooth
waveform to determine the on time of PFC gate.
Normally, with lower feedback loop bandwidth, the
variation of the PFC gate on time should be very small
and almost constant within one input AC cycle.
However, the power factor correction circuit operating at
light-load condition has a defect (zero crossing
distortion) that distorts input current and makes the
systems Total Harmonic Distortion (THD) worse. To
improve the result of THD at light-load condition,
especially at high input voltage, an innovative THD
optimizer is inserted by sampling the voltage across the
current-sense resistor. This sampling voltage on
current-sense resistor is added into the sawtooth
waveform to modulate the on time of PFC gate, so it is
not constant on time within a half AC cycle. The method
of operation between THD optimizer and PWM is shown
in Figure 26. After THD optimizer processes, around the
valley of AC input voltage, the compensated on time
becomes wider than the original. The PFC on time,
which is around the peak voltage, is narrowed by the
THD optimizer. The timing sequences of the PFC MOS
and the shape of the inductor current are shown in
Figure 27. Figure 28 shows the difference between
calculated fixed on time and fixed on time with THD
optimizer during a half AC cycle.
4
3
2 .5 V
IN V
P F C V
O
E rro r
A m p lifie r
V
C O M P
R S
F ilp -F lo p
C S P F C
P F C
M O S
R
S
F A N 6 9 2 1
S a w to o th
G e n e ra to r
T H D
O p tim iz e r
R
1
R
2
Figure 26. Multi-Vector Error Amplifier with
THD Optimizer
I
L, A V G
( f ix e d O n - T im e )
I
L , A V G
( w it h T H D O p t im iz e r )
O N
O F F
G a te S ig n a l
w ith
T H D O p tim iz e r
V
CO M P
S a w to o th
G a te S ig n a l
w ith F ix e d
Figure 27. Operation Waveforms of Fixed On Time
with and without THD Optimizer
0
0.0014 0.0028 0.0042 0.0056 0.0069 0.0083
0
0.3
0.6
0.9
1.2
1.5
1.8
Fixed O n-tim e w ith T H D O ptim izer
Fixed O n tim e
Input C urrent
Tim e (Seconds)
P
O
: 9 0 W
In p u t V o lta g e : 9 0 V A C
P F C In d u cto r : 4 6 0 m H
C S R esisto r : 0 .1 5 W
Figure 28. Calculated Waveforms of Fixed On Time
with and without THD Optimizer During a Half
AC Cycle
相關PDF資料 |
PDF描述 |
|---|---|
| FAN6921MRMY | IC CTLR PFC/FLYBACK 16-SOICN |
| FAN6961SZ | IC PFC CONTROLLER DCM 8SOP |
| FAN6982MY | IC CTLR PFC CCM 14-SOICN |
| FAN7527BN | IC PFC CTRLR TRANSITION 8DIP |
| FAN7529MX | IC PFC CTRLR CRM/TRANSITION 8SOP |
相關代理商/技術參數 |
參數描述 |
|---|---|
| FAN6921MR | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Integrated Critical-Mode PFC / Quasi-Resonant Current-Mode PWM Controller |
| FAN6921MRMY | 功能描述:電流型 PWM 控制器 Crtcl Md PFC & Quasi Res Cur Md PWM Cntlr RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| FAN6961 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Interleaved Dual BCM PFC Controllers |
| FAN6961BMY | 制造商:Fairchild Semiconductor Corporation 功能描述: |
| FAN6961DY | 功能描述:功率因數校正 IC Green mode PFC Fwd PWM Controller 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 |
發布緊急采購，3分鐘左右您將得到回復。