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參數(shù)資料
| 型號： | FSDL321L |
| 廠商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Green Mode Fairchild Power Switch (FPS TM) |
| 中文描述： | 1.5 A SWITCHING REGULATOR, 55 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | SOP-8 |
| 文件頁數(shù)： | 12/20頁 |
| 文件大小： | 479K |
| 代理商： | FSDL321L |
FSDL0165RN
12
Figure 8. Soft Start Function
6. Burst operation :
In order to minimize power
dissipation in
standby mode, the FPS
TM
enters burst mode
operation.
Figure 9. Circuit for Burst operation
As the load decreases, the feedback voltage decreases. As shown in
figure 10, the device automatically enters burst mode when the
feedback voltage drops below V
BURH
(500mV). Switching still con-
tinues but the current limit is set to a fixed limit internally to mini-
mize flux density in the transformer. The fixed current limit is
larger than that defined by Vfb = V
BURH
and therefore, Vfb is
driven down further.
Switching continues until
the feedback
voltage drops below V
BURL
(300mV). At
this point switching
stops and the output voltages start to drop at a rate dependent
on the standby current load. This causes the feedback volt-
age to rise. Once it passes
V
BURH
(500mV) switching resumes.
The feedback
voltage then falls and the process repeats. Burst
mode operation alternately enables and disables switching of
the power Sense FET thereby reducing switching loss in
Standby mode.
Figure 10. Circuit for Burst Operation
7. Frequency Modulation
: EMI reduction can be accom-
plished by modulating the switching frequency of a switched
power supply. Frequency modulation can reduce EMI by
spreading the energy over a wider frequency range than the
band width measured by the EMI test equipment. The
amount of EMI reduction is directly related to the depth of
the reference frequency. As can be seen in Figure 11, the fre-
quency changes from 65KHz to 69KHz in 4mS for the
FSDM0265RN. Frequency modulation allows the use of a
cost effective inductor instead of an AC input mode choke to
satisfy the requirements of world wide EMI limits.
Figure 11. Frequency Modulation Waveform
D R A IN
G N D
R se nse
I_o ve r
S W IT C H
O F F
5 V
3
Vcc
Vcc
I
delay
I
FB
R
2.5R
FB
0.3/0.5V
PWM
+
-
0.5V
Vcc
I
B_PEAK
Burst
Normal
MOSFET
Current
0.5V
Switching OFF
Current
waveform
Burst Operation
Normal Operation
Feedback
0.3V
Burst Operation
Switching OFF
69kHz
69kHz
67kHz
65kHz
4kHz
Turn-on
Turn-off
point
Internal
Oscillator
Drain to
Source
voltage
Vds
Waveform
Drain to
Source
current
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| FSDH0565 | Green Mode Fairchild Power Switch (FPSTM) |
| FSD200 | Green Mode Fairchild Power Switch (FPSTM) |
| FSD200M | Green Mode Fairchild Power Switch (FPSTM) |
| FSD210M | Green Mode Fairchild Power Switch (FPSTM) |
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| FSDL321L_Q | 功能描述:電源開關 IC - 配電 FPS for DVDP/STB RoHS:否 制造商:Exar 輸出端數(shù)量:1 開啟電阻（最大值）:85 mOhms 開啟時間（最大值）:400 us 關閉時間（最大值）:20 us 工作電源電壓:3.2 V to 6.5 V 電源電流（最大值）: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOT-23-5 |
| FSDLC01G-S | 制造商:AXIOMTEK 制造商全稱:AXIOMTEK 功能描述:Capacity: 128MB to 32GB |
| FSDLC128-S | 制造商:AXIOMTEK 制造商全稱:AXIOMTEK 功能描述:Capacity: 128MB to 32GB |
| FSDLC16G-S | 制造商:AXIOMTEK 制造商全稱:AXIOMTEK 功能描述:Capacity: 128MB to 32GB |
| FSDLC256-S | 制造商:AXIOMTEK 制造商全稱:AXIOMTEK 功能描述:Capacity: 128MB to 32GB |
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